X-Git-Url: http://git.videolan.org/?p=ffmpeg.git;a=blobdiff_plain;f=doc%2Ffilters.texi;h=ce7417a00c03350f93f1274f88ef0269e559cf92;hp=07761cf2cf55b42ec2d73e111babe6b3d8f22a88;hb=94ec709e3bdd37368ecfc2973ff931fa4cb775c0;hpb=ee0e8d4b15a87932ab6066cd6eae3cab08726319 diff --git a/doc/filters.texi b/doc/filters.texi index 07761cf2cf..ce7417a00c 100644 --- a/doc/filters.texi +++ b/doc/filters.texi @@ -1,3 +1,99 @@ +@chapter Filtering Introduction +@c man begin FILTERING INTRODUCTION + +Filtering in FFmpeg is enabled through the libavfilter library. + +In libavfilter, a filter can have multiple inputs and multiple +outputs. +To illustrate the sorts of things that are possible, we consider the +following filtergraph. + +@example +input --> split ---------------------> overlay --> output + | ^ + | | + +-----> crop --> vflip -------+ +@end example + +This filtergraph splits the input stream in two streams, sends one +stream through the crop filter and the vflip filter before merging it +back with the other stream by overlaying it on top. You can use the +following command to achieve this: + +@example +ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT +@end example + +The result will be that in output the top half of the video is mirrored +onto the bottom half. + +Filters in the same linear chain are separated by commas, and distinct +linear chains of filters are separated by semicolons. In our example, +@var{crop,vflip} are in one linear chain, @var{split} and +@var{overlay} are separately in another. The points where the linear +chains join are labelled by names enclosed in square brackets. In the +example, the split filter generates two outputs that are associated to +the labels @var{[main]} and @var{[tmp]}. + +The stream sent to the second output of @var{split}, labelled as +@var{[tmp]}, is processed through the @var{crop} filter, which crops +away the lower half part of the video, and then vertically flipped. The +@var{overlay} filter takes in input the first unchanged output of the +split filter (which was labelled as @var{[main]}), and overlay on its +lower half the output generated by the @var{crop,vflip} filterchain. + +Some filters take in input a list of parameters: they are specified +after the filter name and an equal sign, and are separated from each other +by a colon. + +There exist so-called @var{source filters} that do not have an +audio/video input, and @var{sink filters} that will not have audio/video +output. + +@c man end FILTERING INTRODUCTION + +@chapter graph2dot +@c man begin GRAPH2DOT + +The @file{graph2dot} program included in the FFmpeg @file{tools} +directory can be used to parse a filtergraph description and issue a +corresponding textual representation in the dot language. + +Invoke the command: +@example +graph2dot -h +@end example + +to see how to use @file{graph2dot}. + +You can then pass the dot description to the @file{dot} program (from +the graphviz suite of programs) and obtain a graphical representation +of the filtergraph. + +For example the sequence of commands: +@example +echo @var{GRAPH_DESCRIPTION} | \ +tools/graph2dot -o graph.tmp && \ +dot -Tpng graph.tmp -o graph.png && \ +display graph.png +@end example + +can be used to create and display an image representing the graph +described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be +a complete self-contained graph, with its inputs and outputs explicitly defined. +For example if your command line is of the form: +@example +ffmpeg -i infile -vf scale=640:360 outfile +@end example +your @var{GRAPH_DESCRIPTION} string will need to be of the form: +@example +nullsrc,scale=640:360,nullsink +@end example +you may also need to set the @var{nullsrc} parameters and add a @var{format} +filter in order to simulate a specific input file. + +@c man end GRAPH2DOT + @chapter Filtergraph description @c man begin FILTERGRAPH DESCRIPTION @@ -19,7 +115,7 @@ output pads is called a "sink". A filtergraph can be represented using a textual representation, which is recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex} -options in @command{avconv} and @option{-vf} in @command{avplay}, and by the +options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the @code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in @file{libavfilter/avfiltergraph.h}. @@ -112,21 +208,488 @@ Follows a BNF description for the filtergraph syntax: @var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}] @end example +@section Notes on filtergraph escaping + +Some filter arguments require the use of special characters, typically +@code{:} to separate key=value pairs in a named options list. In this +case the user should perform a first level escaping when specifying +the filter arguments. For example, consider the following literal +string to be embedded in the @ref{drawtext} filter arguments: +@example +this is a 'string': may contain one, or more, special characters +@end example + +Since @code{:} is special for the filter arguments syntax, it needs to +be escaped, so you get: +@example +text=this is a \'string\'\: may contain one, or more, special characters +@end example + +A second level of escaping is required when embedding the filter +arguments in a filtergraph description, in order to escape all the +filtergraph special characters. Thus the example above becomes: +@example +drawtext=text=this is a \\\'string\\\'\\: may contain one\, or more\, special characters +@end example + +Finally an additional level of escaping may be needed when writing the +filtergraph description in a shell command, which depends on the +escaping rules of the adopted shell. For example, assuming that +@code{\} is special and needs to be escaped with another @code{\}, the +previous string will finally result in: +@example +-vf "drawtext=text=this is a \\\\\\'string\\\\\\'\\\\: may contain one\\, or more\\, special characters" +@end example + +Sometimes, it might be more convenient to employ quoting in place of +escaping. For example the string: +@example +Caesar: tu quoque, Brute, fili mi +@end example + +Can be quoted in the filter arguments as: +@example +text='Caesar: tu quoque, Brute, fili mi' +@end example + +And finally inserted in a filtergraph like: +@example +drawtext=text=\'Caesar: tu quoque\, Brute\, fili mi\' +@end example + +See the ``Quoting and escaping'' section in the ffmpeg-utils manual +for more information about the escaping and quoting rules adopted by +FFmpeg. + @c man end FILTERGRAPH DESCRIPTION @chapter Audio Filters @c man begin AUDIO FILTERS -When you configure your Libav build, you can disable any of the -existing filters using --disable-filters. +When you configure your FFmpeg build, you can disable any of the +existing filters using @code{--disable-filters}. The configure output will show the audio filters included in your build. Below is a description of the currently available audio filters. +@section aconvert + +Convert the input audio format to the specified formats. + +The filter accepts a string of the form: +"@var{sample_format}:@var{channel_layout}". + +@var{sample_format} specifies the sample format, and can be a string or the +corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p' +suffix for a planar sample format. + +@var{channel_layout} specifies the channel layout, and can be a string +or the corresponding number value defined in @file{libavutil/channel_layout.h}. + +The special parameter "auto", signifies that the filter will +automatically select the output format depending on the output filter. + +@subsection Examples + +@itemize +@item +Convert input to float, planar, stereo: +@example +aconvert=fltp:stereo +@end example + +@item +Convert input to unsigned 8-bit, automatically select out channel layout: +@example +aconvert=u8:auto +@end example +@end itemize + +@section allpass + +Apply a two-pole all-pass filter with central frequency (in Hz) +@var{frequency}, and filter-width @var{width}. +An all-pass filter changes the audio's frequency to phase relationship +without changing its frequency to amplitude relationship. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item frequency, f +Set frequency in Hz. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Specify the band-width of a filter in width_type units. +@end table + +@section highpass + +Apply a high-pass filter with 3dB point frequency. +The filter can be either single-pole, or double-pole (the default). +The filter roll off at 6dB per pole per octave (20dB per pole per decade). + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item frequency, f +Set frequency in Hz. Default is 3000. + +@item poles, p +Set number of poles. Default is 2. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Specify the band-width of a filter in width_type units. +Applies only to double-pole filter. +The default is 0.707q and gives a Butterworth response. +@end table + +@section lowpass + +Apply a low-pass filter with 3dB point frequency. +The filter can be either single-pole or double-pole (the default). +The filter roll off at 6dB per pole per octave (20dB per pole per decade). + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item frequency, f +Set frequency in Hz. Default is 500. + +@item poles, p +Set number of poles. Default is 2. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Specify the band-width of a filter in width_type units. +Applies only to double-pole filter. +The default is 0.707q and gives a Butterworth response. +@end table + +@section bass + +Boost or cut the bass (lower) frequencies of the audio using a two-pole +shelving filter with a response similar to that of a standard +hi-fi's tone-controls. This is also known as shelving equalisation (EQ). + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item gain, g +Give the gain at 0 Hz. Its useful range is about -20 +(for a large cut) to +20 (for a large boost). +Beware of clipping when using a positive gain. + +@item frequency, f +Set the filter's central frequency and so can be used +to extend or reduce the frequency range to be boosted or cut. +The default value is @code{100} Hz. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Determine how steep is the filter's shelf transition. +@end table + +@section treble + +Boost or cut treble (upper) frequencies of the audio using a two-pole +shelving filter with a response similar to that of a standard +hi-fi's tone-controls. This is also known as shelving equalisation (EQ). + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item gain, g +Give the gain at whichever is the lower of ~22 kHz and the +Nyquist frequency. Its useful range is about -20 (for a large cut) +to +20 (for a large boost). Beware of clipping when using a positive gain. + +@item frequency, f +Set the filter's central frequency and so can be used +to extend or reduce the frequency range to be boosted or cut. +The default value is @code{3000} Hz. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Determine how steep is the filter's shelf transition. +@end table + +@section bandpass + +Apply a two-pole Butterworth band-pass filter with central +frequency @var{frequency}, and (3dB-point) band-width width. +The @var{csg} option selects a constant skirt gain (peak gain = Q) +instead of the default: constant 0dB peak gain. +The filter roll off at 6dB per octave (20dB per decade). + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item frequency, f +Set the filter's central frequency. Default is @code{3000}. + +@item csg +Constant skirt gain if set to 1. Defaults to 0. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Specify the band-width of a filter in width_type units. +@end table + +@section bandreject + +Apply a two-pole Butterworth band-reject filter with central +frequency @var{frequency}, and (3dB-point) band-width @var{width}. +The filter roll off at 6dB per octave (20dB per decade). + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item frequency, f +Set the filter's central frequency. Default is @code{3000}. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Specify the band-width of a filter in width_type units. +@end table + +@section biquad + +Apply a biquad IIR filter with the given coefficients. +Where @var{b0}, @var{b1}, @var{b2} and @var{a0}, @var{a1}, @var{a2} +are the numerator and denominator coefficients respectively. + +@section equalizer + +Apply a two-pole peaking equalisation (EQ) filter. With this +filter, the signal-level at and around a selected frequency can +be increased or decreased, whilst (unlike bandpass and bandreject +filters) that at all other frequencies is unchanged. + +In order to produce complex equalisation curves, this filter can +be given several times, each with a different central frequency. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item frequency, f +Set the filter's central frequency in Hz. + +@item width_type +Set method to specify band-width of filter. +@table @option +@item h +Hz +@item q +Q-Factor +@item o +octave +@item s +slope +@end table + +@item width, w +Specify the band-width of a filter in width_type units. + +@item gain, g +Set the required gain or attenuation in dB. +Beware of clipping when using a positive gain. +@end table + +@section afade + +Apply fade-in/out effect to input audio. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". + +A description of the accepted parameters follows. + +@table @option +@item type, t +Specify the effect type, can be either @code{in} for fade-in, or +@code{out} for a fade-out effect. Default is @code{in}. + +@item start_sample, ss +Specify the number of the start sample for starting to apply the fade +effect. Default is 0. + +@item nb_samples, ns +Specify the number of samples for which the fade effect has to last. At +the end of the fade-in effect the output audio will have the same +volume as the input audio, at the end of the fade-out transition +the output audio will be silence. Default is 44100. + +@item start_time, st +Specify time in seconds for starting to apply the fade +effect. Default is 0. +If set this option is used instead of @var{start_sample} one. + +@item duration, d +Specify the number of seconds for which the fade effect has to last. At +the end of the fade-in effect the output audio will have the same +volume as the input audio, at the end of the fade-out transition +the output audio will be silence. Default is 0. +If set this option is used instead of @var{nb_samples} one. + +@item curve +Set curve for fade transition. + +It accepts the following values: +@table @option +@item tri +select triangular, linear slope (default) +@item qsin +select quarter of sine wave +@item hsin +select half of sine wave +@item esin +select exponential sine wave +@item log +select logarithmic +@item par +select inverted parabola +@item qua +select quadratic +@item cub +select cubic +@item squ +select square root +@item cbr +select cubic root +@end table +@end table + +@subsection Examples + +@itemize +@item +Fade in first 15 seconds of audio: +@example +afade=t=in:ss=0:d=15 +@end example + +@item +Fade out last 25 seconds of a 900 seconds audio: +@example +afade=t=out:ss=875:d=25 +@end example +@end itemize + +@anchor{aformat} @section aformat -Convert the input audio to one of the specified formats. The framework will +Set output format constraints for the input audio. The framework will negotiate the most appropriate format to minimize conversions. The filter accepts the following named parameters: @@ -150,13 +713,71 @@ For example to force the output to either unsigned 8-bit or signed 16-bit stereo aformat=sample_fmts=u8|s16:channel_layouts=stereo @end example +@section amerge + +Merge two or more audio streams into a single multi-channel stream. + +The filter accepts the following named options: + +@table @option + +@item inputs +Set the number of inputs. Default is 2. + +@end table + +If the channel layouts of the inputs are disjoint, and therefore compatible, +the channel layout of the output will be set accordingly and the channels +will be reordered as necessary. If the channel layouts of the inputs are not +disjoint, the output will have all the channels of the first input then all +the channels of the second input, in that order, and the channel layout of +the output will be the default value corresponding to the total number of +channels. + +For example, if the first input is in 2.1 (FL+FR+LF) and the second input +is FC+BL+BR, then the output will be in 5.1, with the channels in the +following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the +first input, b1 is the first channel of the second input). + +On the other hand, if both input are in stereo, the output channels will be +in the default order: a1, a2, b1, b2, and the channel layout will be +arbitrarily set to 4.0, which may or may not be the expected value. + +All inputs must have the same sample rate, and format. + +If inputs do not have the same duration, the output will stop with the +shortest. + +@subsection Examples + +@itemize +@item +Merge two mono files into a stereo stream: +@example +amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge +@end example + +@item +Multiple merges: +@example +ffmpeg -f lavfi -i " +amovie=input.mkv:si=0 [a0]; +amovie=input.mkv:si=1 [a1]; +amovie=input.mkv:si=2 [a2]; +amovie=input.mkv:si=3 [a3]; +amovie=input.mkv:si=4 [a4]; +amovie=input.mkv:si=5 [a5]; +[a0][a1][a2][a3][a4][a5] amerge=inputs=6" -c:a pcm_s16le output.mkv +@end example +@end itemize + @section amix Mixes multiple audio inputs into a single output. For example @example -avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT +ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT @end example will mix 3 input audio streams to a single output with the same duration as the first input and a dropout transition time of 3 seconds. @@ -192,29 +813,102 @@ stream ends. The default value is 2 seconds. Pass the audio source unchanged to the output. -@section ashowinfo - -Show a line containing various information for each input audio frame. -The input audio is not modified. +@section apad -The shown line contains a sequence of key/value pairs of the form -@var{key}:@var{value}. +Pad the end of a audio stream with silence, this can be used together with +-shortest to extend audio streams to the same length as the video stream. -A description of each shown parameter follows: +@anchor{aresample} +@section aresample -@table @option -@item n -sequential number of the input frame, starting from 0 +Resample the input audio to the specified parameters, using the +libswresample library. If none are specified then the filter will +automatically convert between its input and output. -@item pts -Presentation timestamp of the input frame, in time base units; the time base -depends on the filter input pad, and is usually 1/@var{sample_rate}. +This filter is also able to stretch/squeeze the audio data to make it match +the timestamps or to inject silence / cut out audio to make it match the +timestamps, do a combination of both or do neither. -@item pts_time -presentation timestamp of the input frame in seconds +The filter accepts the syntax +[@var{sample_rate}:]@var{resampler_options}, where @var{sample_rate} +expresses a sample rate and @var{resampler_options} is a list of +@var{key}=@var{value} pairs, separated by ":". See the +ffmpeg-resampler manual for the complete list of supported options. -@item fmt -sample format +@subsection Examples + +@itemize +@item +Resample the input audio to 44100Hz: +@example +aresample=44100 +@end example + +@item +Stretch/squeeze samples to the given timestamps, with a maximum of 1000 +samples per second compensation: +@example +aresample=async=1000 +@end example +@end itemize + +@section asetnsamples + +Set the number of samples per each output audio frame. + +The last output packet may contain a different number of samples, as +the filter will flush all the remaining samples when the input audio +signal its end. + +The filter accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". + +@table @option + +@item nb_out_samples, n +Set the number of frames per each output audio frame. The number is +intended as the number of samples @emph{per each channel}. +Default value is 1024. + +@item pad, p +If set to 1, the filter will pad the last audio frame with zeroes, so +that the last frame will contain the same number of samples as the +previous ones. Default value is 1. +@end table + +For example, to set the number of per-frame samples to 1234 and +disable padding for the last frame, use: +@example +asetnsamples=n=1234:p=0 +@end example + +@section ashowinfo + +Show a line containing various information for each input audio frame. +The input audio is not modified. + +The shown line contains a sequence of key/value pairs of the form +@var{key}:@var{value}. + +A description of each shown parameter follows: + +@table @option +@item n +sequential number of the input frame, starting from 0 + +@item pts +Presentation timestamp of the input frame, in time base units; the time base +depends on the filter input pad, and is usually 1/@var{sample_rate}. + +@item pts_time +presentation timestamp of the input frame in seconds + +@item pos +position of the frame in the input stream, -1 if this information in +unavailable and/or meaningless (for example in case of synthetic audio) + +@item fmt +sample format @item chlayout channel layout @@ -240,16 +934,221 @@ Split input audio into several identical outputs. The filter accepts a single parameter which specifies the number of outputs. If unspecified, it defaults to 2. -For example +For example: +@example +[in] asplit [out0][out1] +@end example + +will create two separate outputs from the same input. + +To create 3 or more outputs, you need to specify the number of +outputs, like in: +@example +[in] asplit=3 [out0][out1][out2] +@end example + @example -avconv -i INPUT -filter_complex asplit=5 OUTPUT +ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT @end example will create 5 copies of the input audio. + +@section astreamsync + +Forward two audio streams and control the order the buffers are forwarded. + +The argument to the filter is an expression deciding which stream should be +forwarded next: if the result is negative, the first stream is forwarded; if +the result is positive or zero, the second stream is forwarded. It can use +the following variables: + +@table @var +@item b1 b2 +number of buffers forwarded so far on each stream +@item s1 s2 +number of samples forwarded so far on each stream +@item t1 t2 +current timestamp of each stream +@end table + +The default value is @code{t1-t2}, which means to always forward the stream +that has a smaller timestamp. + +Example: stress-test @code{amerge} by randomly sending buffers on the wrong +input, while avoiding too much of a desynchronization: +@example +amovie=file.ogg [a] ; amovie=file.mp3 [b] ; +[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ; +[a2] [b2] amerge +@end example + +@section atempo + +Adjust audio tempo. + +The filter accepts exactly one parameter, the audio tempo. If not +specified then the filter will assume nominal 1.0 tempo. Tempo must +be in the [0.5, 2.0] range. + +@subsection Examples + +@itemize +@item +Slow down audio to 80% tempo: +@example +atempo=0.8 +@end example + +@item +To speed up audio to 125% tempo: +@example +atempo=1.25 +@end example +@end itemize + +@section earwax + +Make audio easier to listen to on headphones. + +This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio +so that when listened to on headphones the stereo image is moved from +inside your head (standard for headphones) to outside and in front of +the listener (standard for speakers). + +Ported from SoX. + +@section pan + +Mix channels with specific gain levels. The filter accepts the output +channel layout followed by a set of channels definitions. + +This filter is also designed to remap efficiently the channels of an audio +stream. + +The filter accepts parameters of the form: +"@var{l}:@var{outdef}:@var{outdef}:..." + +@table @option +@item l +output channel layout or number of channels + +@item outdef +output channel specification, of the form: +"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]" + +@item out_name +output channel to define, either a channel name (FL, FR, etc.) or a channel +number (c0, c1, etc.) + +@item gain +multiplicative coefficient for the channel, 1 leaving the volume unchanged + +@item in_name +input channel to use, see out_name for details; it is not possible to mix +named and numbered input channels +@end table + +If the `=' in a channel specification is replaced by `<', then the gains for +that specification will be renormalized so that the total is 1, thus +avoiding clipping noise. + +@subsection Mixing examples + +For example, if you want to down-mix from stereo to mono, but with a bigger +factor for the left channel: +@example +pan=1:c0=0.9*c0+0.1*c1 +@end example + +A customized down-mix to stereo that works automatically for 3-, 4-, 5- and +7-channels surround: +@example +pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR +@end example + +Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system +that should be preferred (see "-ac" option) unless you have very specific +needs. + +@subsection Remapping examples + +The channel remapping will be effective if, and only if: + +@itemize +@item gain coefficients are zeroes or ones, +@item only one input per channel output, +@end itemize + +If all these conditions are satisfied, the filter will notify the user ("Pure +channel mapping detected"), and use an optimized and lossless method to do the +remapping. + +For example, if you have a 5.1 source and want a stereo audio stream by +dropping the extra channels: +@example +pan="stereo: c0=FL : c1=FR" +@end example + +Given the same source, you can also switch front left and front right channels +and keep the input channel layout: +@example +pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5" +@end example + +If the input is a stereo audio stream, you can mute the front left channel (and +still keep the stereo channel layout) with: +@example +pan="stereo:c1=c1" +@end example + +Still with a stereo audio stream input, you can copy the right channel in both +front left and right: +@example +pan="stereo: c0=FR : c1=FR" +@end example + +@section silencedetect + +Detect silence in an audio stream. + +This filter logs a message when it detects that the input audio volume is less +or equal to a noise tolerance value for a duration greater or equal to the +minimum detected noise duration. + +The printed times and duration are expressed in seconds. + +@table @option +@item duration, d +Set silence duration until notification (default is 2 seconds). + +@item noise, n +Set noise tolerance. Can be specified in dB (in case "dB" is appended to the +specified value) or amplitude ratio. Default is -60dB, or 0.001. +@end table + +@subsection Examples + +@itemize +@item +Detect 5 seconds of silence with -50dB noise tolerance: +@example +silencedetect=n=-50dB:d=5 +@end example + +@item +Complete example with @command{ffmpeg} to detect silence with 0.0001 noise +tolerance in @file{silence.mp3}: +@example +ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null - +@end example +@end itemize + @section asyncts Synchronize audio data with timestamps by squeezing/stretching it and/or dropping samples/adding silence when needed. +This filter is not built by default, please use @ref{aresample} to do squeezing/stretching. + The filter accepts the following named parameters: @table @option @@ -287,14 +1186,14 @@ Channel layout of the input stream. Default is "stereo". For example, assuming a stereo input MP3 file @example -avconv -i in.mp3 -filter_complex channelsplit out.mkv +ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv @end example will create an output Matroska file with two audio streams, one containing only the left channel and the other the right channel. To split a 5.1 WAV file into per-channel files @example -avconv -i in.wav -filter_complex +ffmpeg -i in.wav -filter_complex 'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]' -map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]' front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]' @@ -324,14 +1223,14 @@ output channels preserving index. For example, assuming a 5.1+downmix input MOV file @example -avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav +ffmpeg -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav @end example will create an output WAV file tagged as stereo from the downmix channels of the input. To fix a 5.1 WAV improperly encoded in AAC's native channel order @example -avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav +ffmpeg -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav @end example @section join @@ -361,27 +1260,31 @@ and if that fails it picks the first unused input channel. E.g. to join 3 inputs (with properly set channel layouts) @example -avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT +ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT @end example To build a 5.1 output from 6 single-channel streams: @example -avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex +ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex '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' out @end example @section resample Convert the audio sample format, sample rate and channel layout. This filter is -not meant to be used directly, it is inserted automatically by libavfilter -whenever conversion is needed. Use the @var{aformat} filter to force a specific -conversion. +not meant to be used directly. @section volume Adjust the input audio volume. -The filter accepts the following named parameters: +The filter accepts the following named parameters. If the key of the +first options is omitted, the arguments are interpreted according to +the following syntax: +@example +volume=@var{volume}:@var{precision} +@end example + @table @option @item volume @@ -397,7 +1300,7 @@ The output audio volume is given by the relation: Default value for @var{volume} is 1.0. @item precision -Mathematical precision. +Set the mathematical precision. This determines which input sample formats will be allowed, which affects the precision of the volume scaling. @@ -423,6 +1326,12 @@ volume=volume=1/2 volume=volume=-6.0206dB @end example +In all the above example the named key for @option{volume} can be +omitted, for example like in: +@example +volume=0.5 +@end example + @item Increase input audio power by 6 decibels using fixed-point precision: @example @@ -430,1337 +1339,5118 @@ volume=volume=6dB:precision=fixed @end example @end itemize -@c man end AUDIO FILTERS +@section volumedetect -@chapter Audio Sources -@c man begin AUDIO SOURCES +Detect the volume of the input video. -Below is a description of the currently available audio sources. +The filter has no parameters. The input is not modified. Statistics about +the volume will be printed in the log when the input stream end is reached. -@section anullsrc +In particular it will show the mean volume (root mean square), maximum +volume (on a per-sample basis), and the beginning of an histogram of the +registered volume values (from the maximum value to a cumulated 1/1000 of +the samples). + +All volumes are in decibels relative to the maximum PCM value. -Null audio source, never return audio frames. It is mainly useful as a -template and to be employed in analysis / debugging tools. +@subsection Examples -It accepts as optional parameter a string of the form -@var{sample_rate}:@var{channel_layout}. +Here is an excerpt of the output: +@example +[Parsed_volumedetect_0 @ 0xa23120] mean_volume: -27 dB +[Parsed_volumedetect_0 @ 0xa23120] max_volume: -4 dB +[Parsed_volumedetect_0 @ 0xa23120] histogram_4db: 6 +[Parsed_volumedetect_0 @ 0xa23120] histogram_5db: 62 +[Parsed_volumedetect_0 @ 0xa23120] histogram_6db: 286 +[Parsed_volumedetect_0 @ 0xa23120] histogram_7db: 1042 +[Parsed_volumedetect_0 @ 0xa23120] histogram_8db: 2551 +[Parsed_volumedetect_0 @ 0xa23120] histogram_9db: 4609 +[Parsed_volumedetect_0 @ 0xa23120] histogram_10db: 8409 +@end example -@var{sample_rate} specify the sample rate, and defaults to 44100. +It means that: +@itemize +@item +The mean square energy is approximately -27 dB, or 10^-2.7. +@item +The largest sample is at -4 dB, or more precisely between -4 dB and -5 dB. +@item +There are 6 samples at -4 dB, 62 at -5 dB, 286 at -6 dB, etc. +@end itemize -@var{channel_layout} specify the channel layout, and can be either an -integer or a string representing a channel layout. The default value -of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO. +In other words, raising the volume by +4 dB does not cause any clipping, +raising it by +5 dB causes clipping for 6 samples, etc. -Check the channel_layout_map definition in -@file{libavutil/channel_layout.c} for the mapping between strings and -channel layout values. +@c man end AUDIO FILTERS -Follow some examples: -@example -# set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO. -anullsrc=48000:4 +@chapter Audio Sources +@c man begin AUDIO SOURCES -# same as -anullsrc=48000:mono -@end example +Below is a description of the currently available audio sources. @section abuffer + Buffer audio frames, and make them available to the filter chain. -This source is not intended to be part of user-supplied graph descriptions but -for insertion by calling programs through the interface defined in -@file{libavfilter/buffersrc.h}. +This source is mainly intended for a programmatic use, in particular +through the interface defined in @file{libavfilter/asrc_abuffer.h}. -It accepts the following named parameters: -@table @option +It accepts the following mandatory parameters: +@var{sample_rate}:@var{sample_fmt}:@var{channel_layout} -@item time_base -Timebase which will be used for timestamps of submitted frames. It must be -either a floating-point number or in @var{numerator}/@var{denominator} form. +@table @option @item sample_rate -Audio sample rate. +The sample rate of the incoming audio buffers. @item sample_fmt -Name of the sample format, as returned by @code{av_get_sample_fmt_name()}. +The sample format of the incoming audio buffers. +Either a sample format name or its corresponging integer representation from +the enum AVSampleFormat in @file{libavutil/samplefmt.h} @item channel_layout -Channel layout of the audio data, in the form that can be accepted by -@code{av_get_channel_layout()}. +The channel layout of the incoming audio buffers. +Either a channel layout name from channel_layout_map in +@file{libavutil/channel_layout.c} or its corresponding integer representation +from the AV_CH_LAYOUT_* macros in @file{libavutil/channel_layout.h} + +@item channels +The number of channels of the incoming audio buffers. +If both @var{channels} and @var{channel_layout} are specified, then they +must be consistent. + @end table -All the parameters need to be explicitly defined. +@subsection Examples -@c man end AUDIO SOURCES +@example +abuffer=44100:s16p:stereo +@end example -@chapter Audio Sinks -@c man begin AUDIO SINKS +will instruct the source to accept planar 16bit signed stereo at 44100Hz. +Since the sample format with name "s16p" corresponds to the number +6 and the "stereo" channel layout corresponds to the value 0x3, this is +equivalent to: +@example +abuffer=44100:6:0x3 +@end example -Below is a description of the currently available audio sinks. +@section aevalsrc -@section anullsink +Generate an audio signal specified by an expression. -Null audio sink, do absolutely nothing with the input audio. It is -mainly useful as a template and to be employed in analysis / debugging -tools. +This source accepts in input one or more expressions (one for each +channel), which are evaluated and used to generate a corresponding +audio signal. -@section abuffersink -This sink is intended for programmatic use. Frames that arrive on this sink can -be retrieved by the calling program using the interface defined in -@file{libavfilter/buffersink.h}. +It accepts the syntax: @var{exprs}[::@var{options}]. +@var{exprs} is a list of expressions separated by ":", one for each +separate channel. In case the @var{channel_layout} is not +specified, the selected channel layout depends on the number of +provided expressions. -This filter accepts no parameters. +@var{options} is an optional sequence of @var{key}=@var{value} pairs, +separated by ":". -@c man end AUDIO SINKS +The description of the accepted options follows. -@chapter Video Filters -@c man begin VIDEO FILTERS +@table @option -When you configure your Libav build, you can disable any of the -existing filters using --disable-filters. -The configure output will show the video filters included in your -build. +@item channel_layout, c +Set the channel layout. The number of channels in the specified layout +must be equal to the number of specified expressions. -Below is a description of the currently available video filters. +@item duration, d +Set the minimum duration of the sourced audio. See the function +@code{av_parse_time()} for the accepted format. +Note that the resulting duration may be greater than the specified +duration, as the generated audio is always cut at the end of a +complete frame. -@section blackframe +If not specified, or the expressed duration is negative, the audio is +supposed to be generated forever. -Detect frames that are (almost) completely black. Can be useful to -detect chapter transitions or commercials. Output lines consist of -the frame number of the detected frame, the percentage of blackness, -the position in the file if known or -1 and the timestamp in seconds. +@item nb_samples, n +Set the number of samples per channel per each output frame, +default to 1024. -In order to display the output lines, you need to set the loglevel at -least to the AV_LOG_INFO value. +@item sample_rate, s +Specify the sample rate, default to 44100. +@end table -The filter accepts the following options: +Each expression in @var{exprs} can contain the following constants: @table @option +@item n +number of the evaluated sample, starting from 0 -@item amount -The percentage of the pixels that have to be below the threshold, defaults to -98. +@item t +time of the evaluated sample expressed in seconds, starting from 0 -@item threshold -Threshold below which a pixel value is considered black, defaults to 32. +@item s +sample rate @end table -@section boxblur +@subsection Examples -Apply boxblur algorithm to the input video. +@itemize +@item +Generate silence: +@example +aevalsrc=0 +@end example -This filter accepts the following options: +@item +Generate a sin signal with frequency of 440 Hz, set sample rate to +8000 Hz: +@example +aevalsrc="sin(440*2*PI*t)::s=8000" +@end example -@table @option - -@item luma_radius -@item luma_power -@item chroma_radius -@item chroma_power -@item alpha_radius -@item alpha_power - -@end table - -Chroma and alpha parameters are optional, if not specified they default -to the corresponding values set for @var{luma_radius} and -@var{luma_power}. - -@var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent -the radius in pixels of the box used for blurring the corresponding -input plane. They are expressions, and can contain the following -constants: -@table @option -@item w, h -the input width and height in pixels - -@item cw, ch -the input chroma image width and height in pixels - -@item hsub, vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. -@end table - -The radius must be a non-negative number, and must not be greater than -the value of the expression @code{min(w,h)/2} for the luma and alpha planes, -and of @code{min(cw,ch)/2} for the chroma planes. - -@var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent -how many times the boxblur filter is applied to the corresponding -plane. - -Some examples follow: - -@itemize +@item +Generate a two channels signal, specify the channel layout (Front +Center + Back Center) explicitly: +@example +aevalsrc="sin(420*2*PI*t):cos(430*2*PI*t)::c=FC|BC" +@end example @item -Apply a boxblur filter with luma, chroma, and alpha radius -set to 2: +Generate white noise: @example -boxblur=luma_radius=2:luma_power=1 +aevalsrc="-2+random(0)" @end example @item -Set luma radius to 2, alpha and chroma radius to 0 +Generate an amplitude modulated signal: @example -boxblur=2:1:0:0:0:0 +aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)" @end example @item -Set luma and chroma radius to a fraction of the video dimension +Generate 2.5 Hz binaural beats on a 360 Hz carrier: @example -boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1 +aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) : 0.1*sin(2*PI*(360+2.5/2)*t)" @end example @end itemize -@section copy - -Copy the input source unchanged to the output. Mainly useful for -testing purposes. +@section anullsrc -@section crop +Null audio source, return unprocessed audio frames. It is mainly useful +as a template and to be employed in analysis / debugging tools, or as +the source for filters which ignore the input data (for example the sox +synth filter). -Crop the input video to given dimensions. +It accepts an optional sequence of @var{key}=@var{value} pairs, +separated by ":". -This filter accepts the following options: +The description of the accepted options follows. @table @option -@item out_w -Width of the output video. +@item sample_rate, s +Specify the sample rate, and defaults to 44100. -@item out_h -Height of the output video. +@item channel_layout, cl -@item x -Horizontal position, in the input video, of the left edge of the output video. +Specify the channel layout, and can be either an integer or a string +representing a channel layout. The default value of @var{channel_layout} +is "stereo". -@item y -Vertical position, in the input video, of the top edge of the output video. +Check the channel_layout_map definition in +@file{libavutil/channel_layout.c} for the mapping between strings and +channel layout values. + +@item nb_samples, n +Set the number of samples per requested frames. @end table -The parameters are expressions containing the following constants: +@subsection Examples -@table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), PHI (golden ratio) +@itemize +@item +Set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO. +@example +anullsrc=r=48000:cl=4 +@end example -@item x, y -the computed values for @var{x} and @var{y}. They are evaluated for -each new frame. +@item +Do the same operation with a more obvious syntax: +@example +anullsrc=r=48000:cl=mono +@end example +@end itemize -@item in_w, in_h -the input width and height +@section abuffer +Buffer audio frames, and make them available to the filter chain. -@item iw, ih -same as @var{in_w} and @var{in_h} +This source is not intended to be part of user-supplied graph descriptions but +for insertion by calling programs through the interface defined in +@file{libavfilter/buffersrc.h}. -@item out_w, out_h -the output (cropped) width and height +It accepts the following named parameters: +@table @option -@item ow, oh -same as @var{out_w} and @var{out_h} +@item time_base +Timebase which will be used for timestamps of submitted frames. It must be +either a floating-point number or in @var{numerator}/@var{denominator} form. -@item n -the number of input frame, starting from 0 +@item sample_rate +Audio sample rate. -@item t -timestamp expressed in seconds, NAN if the input timestamp is unknown +@item sample_fmt +Name of the sample format, as returned by @code{av_get_sample_fmt_name()}. +@item channel_layout +Channel layout of the audio data, in the form that can be accepted by +@code{av_get_channel_layout()}. @end table -The @var{out_w} and @var{out_h} parameters specify the expressions for -the width and height of the output (cropped) video. They are -evaluated just at the configuration of the filter. - -The default value of @var{out_w} is "in_w", and the default value of -@var{out_h} is "in_h". +All the parameters need to be explicitly defined. -The expression for @var{out_w} may depend on the value of @var{out_h}, -and the expression for @var{out_h} may depend on @var{out_w}, but they -cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are -evaluated after @var{out_w} and @var{out_h}. +@section flite -The @var{x} and @var{y} parameters specify the expressions for the -position of the top-left corner of the output (non-cropped) area. They -are evaluated for each frame. If the evaluated value is not valid, it -is approximated to the nearest valid value. +Synthesize a voice utterance using the libflite library. -The default value of @var{x} is "(in_w-out_w)/2", and the default -value for @var{y} is "(in_h-out_h)/2", which set the cropped area at -the center of the input image. +To enable compilation of this filter you need to configure FFmpeg with +@code{--enable-libflite}. -The expression for @var{x} may depend on @var{y}, and the expression -for @var{y} may depend on @var{x}. +Note that the flite library is not thread-safe. -Follow some examples: -@example -# crop the central input area with size 100x100 -crop=out_w=100:out_h=100 +The source accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". -# crop the central input area with size 2/3 of the input video -"crop=out_w=2/3*in_w:out_h=2/3*in_h" +The description of the accepted parameters follows. -# crop the input video central square -crop=out_w=in_h +@table @option -# delimit the rectangle with the top-left corner placed at position -# 100:100 and the right-bottom corner corresponding to the right-bottom -# corner of the input image. -crop=out_w=in_w-100:out_h=in_h-100:x=100:y=100 +@item list_voices +If set to 1, list the names of the available voices and exit +immediately. Default value is 0. -# crop 10 pixels from the left and right borders, and 20 pixels from -# the top and bottom borders -"crop=out_w=in_w-2*10:out_h=in_h-2*20" +@item nb_samples, n +Set the maximum number of samples per frame. Default value is 512. -# keep only the bottom right quarter of the input image -"crop=out_w=in_w/2:out_h=in_h/2:x=in_w/2:y=in_h/2" +@item textfile +Set the filename containing the text to speak. -# crop height for getting Greek harmony -"crop=out_w=in_w:out_h=1/PHI*in_w" +@item text +Set the text to speak. -# trembling effect -"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)" +@item voice, v +Set the voice to use for the speech synthesis. Default value is +@code{kal}. See also the @var{list_voices} option. +@end table -# erratic camera effect depending on timestamp -"crop=out_w=in_w/2:out_h=in_h/2:x=(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):y=(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)" +@subsection Examples -# set x depending on the value of y -"crop=in_w/2:in_h/2:y:10+10*sin(n/10)" +@itemize +@item +Read from file @file{speech.txt}, and synthetize the text using the +standard flite voice: +@example +flite=textfile=speech.txt @end example -@section cropdetect - -Auto-detect crop size. - -Calculate necessary cropping parameters and prints the recommended -parameters through the logging system. The detected dimensions -correspond to the non-black area of the input video. +@item +Read the specified text selecting the @code{slt} voice: +@example +flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt +@end example -This filter accepts the following options: +@item +Input text to ffmpeg: +@example +ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt +@end example -@table @option +@item +Make @file{ffplay} speak the specified text, using @code{flite} and +the @code{lavfi} device: +@example +ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.' +@end example +@end itemize -@item limit -Threshold, which can be optionally specified from nothing (0) to -everything (255), defaults to 24. +For more information about libflite, check: +@url{http://www.speech.cs.cmu.edu/flite/} -@item round -Value which the width/height should be divisible by, defaults to -16. The offset is automatically adjusted to center the video. Use 2 to -get only even dimensions (needed for 4:2:2 video). 16 is best when -encoding to most video codecs. +@section sine -@item reset -Counter that determines after how many frames cropdetect will reset -the previously detected largest video area and start over to detect -the current optimal crop area. Defaults to 0. +Generate an audio signal made of a sine wave with amplitude 1/8. -This can be useful when channel logos distort the video area. 0 -indicates never reset and return the largest area encountered during -playback. -@end table +The audio signal is bit-exact. -@section delogo +It accepts a list of options in the form of @var{key}=@var{value} pairs +separated by ":". If the option name is omitted, the first option is the +frequency and the second option is the beep factor. -Suppress a TV station logo by a simple interpolation of the surrounding -pixels. Just set a rectangle covering the logo and watch it disappear -(and sometimes something even uglier appear - your mileage may vary). +The supported options are: -This filter accepts the following options: @table @option -@item x, y -Specify the top left corner coordinates of the logo. They must be -specified. +@item frequency, f +Set the carrier frequency. Default is 440 Hz. -@item w, h -Specify the width and height of the logo to clear. They must be -specified. +@item beep_factor, b +Enable a periodic beep every second with frequency @var{beep_factor} times +the carrier frequency. Default is 0, meaning the beep is disabled. -@item band, t -Specify the thickness of the fuzzy edge of the rectangle (added to -@var{w} and @var{h}). The default value is 4. +@item sample_rate, s +Specify the sample rate, default is 44100. -@item show -When set to 1, a green rectangle is drawn on the screen to simplify -finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and -@var{band} is set to 4. The default value is 0. +@item duration, d +Specify the duration of the generated audio stream. +@item samples_per_frame +Set the number of samples per output frame, default is 1024. @end table -Some examples follow. +@subsection Examples @itemize @item -Set a rectangle covering the area with top left corner coordinates 0,0 -and size 100x77, setting a band of size 10: +Generate a simple 440 Hz sine wave: @example -delogo=x=0:y=0:w=100:h=77:band=10 +sine +@end example + +@item +Generate a 220 Hz sine wave with a 880 Hz beep each second, for 5 seconds: +@example +sine=220:4:d=5 +sine=f=220:b=4:d=5 +sine=frequency=220:beep_factor=4:duration=5 @end example @end itemize -@section drawbox +@c man end AUDIO SOURCES -Draw a colored box on the input image. +@chapter Audio Sinks +@c man begin AUDIO SINKS -This filter accepts the following options: +Below is a description of the currently available audio sinks. -@table @option +@section abuffersink -@item x, y -Specify the top left corner coordinates of the box. Default to 0. +Buffer audio frames, and make them available to the end of filter chain. -@item width, height -Specify the width and height of the box, if 0 they are interpreted as -the input width and height. Default to 0. +This sink is mainly intended for programmatic use, in particular +through the interface defined in @file{libavfilter/buffersink.h}. -@item color -Specify the color of the box to write, it can be the name of a color -(case insensitive match) or a 0xRRGGBB[AA] sequence. -@end table +It requires a pointer to an AVABufferSinkContext structure, which +defines the incoming buffers' formats, to be passed as the opaque +parameter to @code{avfilter_init_filter} for initialization. -Follow some examples: -@example -# draw a black box around the edge of the input image -drawbox +@section anullsink -# draw a box with color red and an opacity of 50% -drawbox=x=10:y=20:width=200:height=60:color=red@@0.5" -@end example +Null audio sink, do absolutely nothing with the input audio. It is +mainly useful as a template and to be employed in analysis / debugging +tools. -@section drawtext +@section abuffersink +This sink is intended for programmatic use. Frames that arrive on this sink can +be retrieved by the calling program using the interface defined in +@file{libavfilter/buffersink.h}. -Draw text string or text from specified file on top of video using the -libfreetype library. +This filter accepts no parameters. -To enable compilation of this filter you need to configure Libav with -@code{--enable-libfreetype}. +@c man end AUDIO SINKS -The filter also recognizes strftime() sequences in the provided text -and expands them accordingly. Check the documentation of strftime(). +@chapter Video Filters +@c man begin VIDEO FILTERS -The description of the accepted parameters follows. +When you configure your FFmpeg build, you can disable any of the +existing filters using @code{--disable-filters}. +The configure output will show the video filters included in your +build. -@table @option +Below is a description of the currently available video filters. -@item fontfile -The font file to be used for drawing text. Path must be included. -This parameter is mandatory. +@section alphaextract -@item text -The text string to be drawn. The text must be a sequence of UTF-8 -encoded characters. -This parameter is mandatory if no file is specified with the parameter -@var{textfile}. +Extract the alpha component from the input as a grayscale video. This +is especially useful with the @var{alphamerge} filter. -@item textfile -A text file containing text to be drawn. The text must be a sequence -of UTF-8 encoded characters. +@section alphamerge -This parameter is mandatory if no text string is specified with the -parameter @var{text}. +Add or replace the alpha component of the primary input with the +grayscale value of a second input. This is intended for use with +@var{alphaextract} to allow the transmission or storage of frame +sequences that have alpha in a format that doesn't support an alpha +channel. -If both text and textfile are specified, an error is thrown. +For example, to reconstruct full frames from a normal YUV-encoded video +and a separate video created with @var{alphaextract}, you might use: +@example +movie=in_alpha.mkv [alpha]; [in][alpha] alphamerge [out] +@end example -@item x, y -The offsets where text will be drawn within the video frame. -Relative to the top/left border of the output image. -They accept expressions similar to the @ref{overlay} filter: -@table @option +Since this filter is designed for reconstruction, it operates on frame +sequences without considering timestamps, and terminates when either +input reaches end of stream. This will cause problems if your encoding +pipeline drops frames. If you're trying to apply an image as an +overlay to a video stream, consider the @var{overlay} filter instead. -@item x, y -the computed values for @var{x} and @var{y}. They are evaluated for -each new frame. +@section ass -@item main_w, main_h -main input width and height +Same as the @ref{subtitles} filter, except that it doesn't require libavcodec +and libavformat to work. On the other hand, it is limited to ASS (Advanced +Substation Alpha) subtitles files. -@item W, H -same as @var{main_w} and @var{main_h} +@section bbox -@item text_w, text_h -rendered text width and height +Compute the bounding box for the non-black pixels in the input frame +luminance plane. -@item w, h -same as @var{text_w} and @var{text_h} +This filter computes the bounding box containing all the pixels with a +luminance value greater than the minimum allowed value. +The parameters describing the bounding box are printed on the filter +log. -@item n -the number of frames processed, starting from 0 +@section blackdetect -@item t -timestamp expressed in seconds, NAN if the input timestamp is unknown +Detect video intervals that are (almost) completely black. Can be +useful to detect chapter transitions, commercials, or invalid +recordings. Output lines contains the time for the start, end and +duration of the detected black interval expressed in seconds. -@end table +In order to display the output lines, you need to set the loglevel at +least to the AV_LOG_INFO value. -The default value of @var{x} and @var{y} is 0. +This filter accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. -@item fontsize -The font size to be used for drawing text. -The default value of @var{fontsize} is 16. +@table @option +@item black_min_duration, d +Set the minimum detected black duration expressed in seconds. It must +be a non-negative floating point number. -@item fontcolor -The color to be used for drawing fonts. -Either a string (e.g. "red") or in 0xRRGGBB[AA] format -(e.g. "0xff000033"), possibly followed by an alpha specifier. -The default value of @var{fontcolor} is "black". +Default value is 2.0. -@item boxcolor -The color to be used for drawing box around text. -Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format -(e.g. "0xff00ff"), possibly followed by an alpha specifier. -The default value of @var{boxcolor} is "white". +@item picture_black_ratio_th, pic_th +Set the threshold for considering a picture "black". +Express the minimum value for the ratio: +@example +@var{nb_black_pixels} / @var{nb_pixels} +@end example -@item box -Used to draw a box around text using background color. -Value should be either 1 (enable) or 0 (disable). -The default value of @var{box} is 0. +for which a picture is considered black. +Default value is 0.98. -@item shadowx, shadowy +@item pixel_black_th, pix_th +Set the threshold for considering a pixel "black". + +The threshold expresses the maximum pixel luminance value for which a +pixel is considered "black". The provided value is scaled according to +the following equation: +@example +@var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size} +@end example + +@var{luminance_range_size} and @var{luminance_minimum_value} depend on +the input video format, the range is [0-255] for YUV full-range +formats and [16-235] for YUV non full-range formats. + +Default value is 0.10. +@end table + +The following example sets the maximum pixel threshold to the minimum +value, and detects only black intervals of 2 or more seconds: +@example +blackdetect=d=2:pix_th=0.00 +@end example + +@section blackframe + +Detect frames that are (almost) completely black. Can be useful to +detect chapter transitions or commercials. Output lines consist of +the frame number of the detected frame, the percentage of blackness, +the position in the file if known or -1 and the timestamp in seconds. + +In order to display the output lines, you need to set the loglevel at +least to the AV_LOG_INFO value. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +blackframe[=@var{amount}[:@var{threshold}]]. + +The filter accepts the following options: + +@table @option + +@item amount +The percentage of the pixels that have to be below the threshold, defaults to +98. + +@item threshold +Threshold below which a pixel value is considered black, defaults to 32. + +@end table + +@section blend + +Blend two video frames into each other. + +It takes two input streams and outputs one stream, the first input is the +"top" layer and second input is "bottom" layer. +Output terminates when shortest input terminates. + +This filter accepts a list of options in the form of @var{key}=@var{value} +pairs separated by ":". A description of the accepted options follows. + +@table @option +@item c0_mode +@item c1_mode +@item c2_mode +@item c3_mode +@item all_mode +Set blend mode for specific pixel component or all pixel components in case +of @var{all_mode}. Default value is @code{normal}. + +Available values for component modes are: +@table @samp +@item addition +@item and +@item average +@item burn +@item darken +@item difference +@item divide +@item dodge +@item exclusion +@item hardlight +@item lighten +@item multiply +@item negation +@item normal +@item or +@item overlay +@item phoenix +@item pinlight +@item reflect +@item screen +@item softlight +@item subtract +@item vividlight +@item xor +@end table + +@item c0_opacity +@item c1_opacity +@item c2_opacity +@item c3_opacity +@item all_opacity +Set blend opacity for specific pixel component or all pixel components in case +of @var{all_opacity}. Only used in combination with pixel component blend modes. + +@item c0_expr +@item c1_expr +@item c2_expr +@item c3_expr +@item all_expr +Set blend expression for specific pixel component or all pixel components in case +of @var{all_expr}. Note that related mode options will be ignored if those are set. + +The expressions can use the following variables: + +@table @option +@item N +The sequential number of the filtered frame, starting from @code{0}. + +@item X +@item Y +the coordinates of the current sample + +@item W +@item H +the width and height of currently filtered plane + +@item SW +@item SH +Width and height scale depending on the currently filtered plane. It is the +ratio between the corresponding luma plane number of pixels and the current +plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and +@code{0.5,0.5} for chroma planes. + +@item T +Time of the current frame, expressed in seconds. + +@item TOP, A +Value of pixel component at current location for first video frame (top layer). + +@item BOTTOM, B +Value of pixel component at current location for second video frame (bottom layer). +@end table +@end table + +@subsection Examples + +@itemize +@item +Apply transition from bottom layer to top layer in first 10 seconds: +@example +blend=all_expr='A*(if(gte(T,10),1,T/10))+B*(1-(if(gte(T,10),1,T/10)))' +@end example + +@item +Apply 1x1 checkerboard effect: +@example +blend=all_expr='if(eq(mod(X,2),mod(Y,2)),A,B)' +@end example +@end itemize + +@section boxblur + +Apply boxblur algorithm to the input video. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +@option{luma_radius}:@option{luma_power}:@option{chroma_radius}:@option{chroma_power}:@option{alpha_radius}:@option{alpha_power}. + +This filter accepts the following options: + +@table @option + +@item luma_radius +@item luma_power +@item chroma_radius +@item chroma_power +@item alpha_radius +@item alpha_power + +@end table + +A description of the accepted options follows. + +@table @option +@item luma_radius, lr +@item chroma_radius, cr +@item alpha_radius, ar +Set an expression for the box radius in pixels used for blurring the +corresponding input plane. + +The radius value must be a non-negative number, and must not be +greater than the value of the expression @code{min(w,h)/2} for the +luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma +planes. + +Default value for @option{luma_radius} is "2". If not specified, +@option{chroma_radius} and @option{alpha_radius} default to the +corresponding value set for @option{luma_radius}. + +The expressions can contain the following constants: +@table @option +@item w, h +the input width and height in pixels + +@item cw, ch +the input chroma image width and height in pixels + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@end table + +@item luma_power, lp +@item chroma_power, cp +@item alpha_power, ap +Specify how many times the boxblur filter is applied to the +corresponding plane. + +Default value for @option{luma_power} is 2. If not specified, +@option{chroma_power} and @option{alpha_power} default to the +corresponding value set for @option{luma_power}. + +A value of 0 will disable the effect. +@end table + +@subsection Examples + +@itemize +@item +Apply a boxblur filter with luma, chroma, and alpha radius +set to 2: +@example +boxblur=luma_radius=2:luma_power=1 +boxblur=2:1 +@end example + +@item +Set luma radius to 2, alpha and chroma radius to 0: +@example +boxblur=2:1:cr=0:ar=0 +@end example + +@item +Set luma and chroma radius to a fraction of the video dimension: +@example +boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1 +@end example +@end itemize + +@section colormatrix + +Convert color matrix. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +@var{src}:@var{dst}. + +A description of the accepted options follows: +@table @option +@item src +@item dst +Specify the source and destination color matrix. Both values must be +specified. + +The accepted values are: +@table @samp +@item bt709 +BT.709 + +@item bt601 +BT.601 + +@item smpte240m +SMPTE-240M + +@item fcc +FCC +@end table +@end table + +For example to convert from BT.601 to SMPTE-240M, use the command: +@example +colormatrix=bt601:smpte240m +@end example + +@section copy + +Copy the input source unchanged to the output. Mainly useful for +testing purposes. + +@section crop + +Crop the input video to given dimensions. + +This filter accepts a list of @var{key}=@var{value} pairs as argument, +separated by ':'. If the key of the first options is omitted, the +arguments are interpreted according to the syntax +@var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}. + +A description of the accepted options follows: +@table @option +@item w, out_w +Width of the output video. It defaults to @code{iw}. +This expression is evaluated only once during the filter +configuration. + +@item h, out_h +Height of the output video. It defaults to @code{ih}. +This expression is evaluated only once during the filter +configuration. + +@item x +Horizontal position, in the input video, of the left edge of the output video. +It defaults to @code{(in_w-out_w)/2}. +This expression is evaluated per-frame. + +@item y +Vertical position, in the input video, of the top edge of the output video. +It defaults to @code{(in_h-out_h)/2}. +This expression is evaluated per-frame. + +@item keep_aspect +If set to 1 will force the output display aspect ratio +to be the same of the input, by changing the output sample aspect +ratio. It defaults to 0. +@end table + +The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are +expressions containing the following constants: + +@table @option +@item x, y +the computed values for @var{x} and @var{y}. They are evaluated for +each new frame. + +@item in_w, in_h +the input width and height + +@item iw, ih +same as @var{in_w} and @var{in_h} + +@item out_w, out_h +the output (cropped) width and height + +@item ow, oh +same as @var{out_w} and @var{out_h} + +@item a +same as @var{iw} / @var{ih} + +@item sar +input sample aspect ratio + +@item dar +input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. + +@item n +the number of input frame, starting from 0 + +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown + +@end table + +The expression for @var{out_w} may depend on the value of @var{out_h}, +and the expression for @var{out_h} may depend on @var{out_w}, but they +cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are +evaluated after @var{out_w} and @var{out_h}. + +The @var{x} and @var{y} parameters specify the expressions for the +position of the top-left corner of the output (non-cropped) area. They +are evaluated for each frame. If the evaluated value is not valid, it +is approximated to the nearest valid value. + +The expression for @var{x} may depend on @var{y}, and the expression +for @var{y} may depend on @var{x}. + +@subsection Examples + +@itemize +@item +Crop area with size 100x100 at position (12,34). +@example +crop=100:100:12:34 +@end example + +Using named options, the example above becomes: +@example +crop=w=100:h=100:x=12:y=34 +@end example + +@item +Crop the central input area with size 100x100: +@example +crop=100:100 +@end example + +@item +Crop the central input area with size 2/3 of the input video: +@example +crop=2/3*in_w:2/3*in_h +@end example + +@item +Crop the input video central square: +@example +crop=out_w=in_h +crop=in_h +@end example + +@item +Delimit the rectangle with the top-left corner placed at position +100:100 and the right-bottom corner corresponding to the right-bottom +corner of the input image: +@example +crop=in_w-100:in_h-100:100:100 +@end example + +@item +Crop 10 pixels from the left and right borders, and 20 pixels from +the top and bottom borders +@example +crop=in_w-2*10:in_h-2*20 +@end example + +@item +Keep only the bottom right quarter of the input image: +@example +crop=in_w/2:in_h/2:in_w/2:in_h/2 +@end example + +@item +Crop height for getting Greek harmony: +@example +crop=in_w:1/PHI*in_w +@end example + +@item +Appply trembling effect: +@example +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) +@end example + +@item +Apply erratic camera effect depending on timestamp: +@example +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)" +@end example + +@item +Set x depending on the value of y: +@example +crop=in_w/2:in_h/2:y:10+10*sin(n/10) +@end example +@end itemize + +@section cropdetect + +Auto-detect crop size. + +Calculate necessary cropping parameters and prints the recommended +parameters through the logging system. The detected dimensions +correspond to the non-black area of the input video. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +[@option{limit}[:@option{round}[:@option{reset}]]]. + +A description of the accepted options follows. + +@table @option + +@item limit +Set higher black value threshold, which can be optionally specified +from nothing (0) to everything (255). An intensity value greater +to the set value is considered non-black. Default value is 24. + +@item round +Set the value for which the width/height should be divisible by. The +offset is automatically adjusted to center the video. Use 2 to get +only even dimensions (needed for 4:2:2 video). 16 is best when +encoding to most video codecs. Default value is 16. + +@item reset +Set the counter that determines after how many frames cropdetect will +reset the previously detected largest video area and start over to +detect the current optimal crop area. Default value is 0. + +This can be useful when channel logos distort the video area. 0 +indicates never reset and return the largest area encountered during +playback. +@end table + +@section curves + +Apply color adjustments using curves. + +This filter is similar to the Adobe Photoshop and GIMP curves tools. Each +component (red, green and blue) has its values defined by @var{N} key points +tied from each other using a smooth curve. The x-axis represents the pixel +values from the input frame, and the y-axis the new pixel values to be set for +the output frame. + +By default, a component curve is defined by the two points @var{(0;0)} and +@var{(1;1)}. This creates a straight line where each original pixel value is +"adjusted" to its own value, which means no change to the image. + +The filter allows you to redefine these two points and add some more. A new +curve (using a natural cubic spline interpolation) will be define to pass +smoothly through all these new coordinates. The new defined points needs to be +strictly increasing over the x-axis, and their @var{x} and @var{y} values must +be in the @var{[0;1]} interval. If the computed curves happened to go outside +the vector spaces, the values will be clipped accordingly. + +If there is no key point defined in @code{x=0}, the filter will automatically +insert a @var{(0;0)} point. In the same way, if there is no key point defined +in @code{x=1}, the filter will automatically insert a @var{(1;1)} point. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +curves[=@var{preset}]. + +A description of the accepted parameters follows. + +@table @option +@item red, r +Set the key points for the red component. +@item green, g +Set the key points for the green component. +@item blue, b +Set the key points for the blue component. +@item all +Set the key points for all components. +Can be used in addition to the other key points component +options. In this case, the unset component(s) will fallback on this +@option{all} setting. +@item preset +Select one of the available color presets. This option can not be used in +addition to the @option{r}, @option{g}, @option{b} parameters. +Available presets are: +@table @samp +@item color_negative +@item cross_process +@item darker +@item increase_contrast +@item lighter +@item linear_contrast +@item medium_contrast +@item negative +@item strong_contrast +@item vintage +@end table +Default is unset. +@end table + +To avoid some filtergraph syntax conflicts, each key points list need to be +defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}. + +@subsection Examples + +@itemize +@item +Increase slightly the middle level of blue: +@example +curves=blue='0.5/0.58' +@end example + +@item +Vintage effect: +@example +curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8' +@end example +Here we obtain the following coordinates for each components: +@table @var +@item red +@code{(0;0.11) (0.42;0.51) (1;0.95)} +@item green +@code{(0;0) (0.50;0.48) (1;1)} +@item blue +@code{(0;0.22) (0.49;0.44) (1;0.80)} +@end table + +@item +The previous example can also be achieved with the associated built-in preset: +@example +curves=preset=vintage +@end example + +@item +Or simply: +@example +curves=vintage +@end example +@end itemize + +@section decimate + +Drop frames that do not differ greatly from the previous frame in +order to reduce frame rate. + +The main use of this filter is for very-low-bitrate encoding +(e.g. streaming over dialup modem), but it could in theory be used for +fixing movies that were inverse-telecined incorrectly. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax: +@option{max}:@option{hi}:@option{lo}:@option{frac}. + +A description of the accepted options follows. + +@table @option +@item max +Set the maximum number of consecutive frames which can be dropped (if +positive), or the minimum interval between dropped frames (if +negative). If the value is 0, the frame is dropped unregarding the +number of previous sequentially dropped frames. + +Default value is 0. + +@item hi +@item lo +@item frac +Set the dropping threshold values. + +Values for @option{hi} and @option{lo} are for 8x8 pixel blocks and +represent actual pixel value differences, so a threshold of 64 +corresponds to 1 unit of difference for each pixel, or the same spread +out differently over the block. + +A frame is a candidate for dropping if no 8x8 blocks differ by more +than a threshold of @option{hi}, and if no more than @option{frac} blocks (1 +meaning the whole image) differ by more than a threshold of @option{lo}. + +Default value for @option{hi} is 64*12, default value for @option{lo} is +64*5, and default value for @option{frac} is 0.33. +@end table + +@section delogo + +Suppress a TV station logo by a simple interpolation of the surrounding +pixels. Just set a rectangle covering the logo and watch it disappear +(and sometimes something even uglier appear - your mileage may vary). + +This filter accepts the following options: +@table @option + +@item x, y +Specify the top left corner coordinates of the logo. They must be +specified. + +@item w, h +Specify the width and height of the logo to clear. They must be +specified. + +@item band, t +Specify the thickness of the fuzzy edge of the rectangle (added to +@var{w} and @var{h}). The default value is 4. + +@item show +When set to 1, a green rectangle is drawn on the screen to simplify +finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and +@var{band} is set to 4. The default value is 0. + +@end table + +@subsection Examples + +@itemize +@item +Set a rectangle covering the area with top left corner coordinates 0,0 +and size 100x77, setting a band of size 10: +@example +delogo=x=0:y=0:w=100:h=77:band=10 +@end example + +@end itemize + +@section deshake + +Attempt to fix small changes in horizontal and/or vertical shift. This +filter helps remove camera shake from hand-holding a camera, bumping a +tripod, moving on a vehicle, etc. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +@var{x}:@var{y}:@var{w}:@var{h}:@var{rx}:@var{ry}:@var{edge}:@var{blocksize}:@var{contrast}:@var{search}:@var{filename}:@var{opencl}. + +A description of the accepted parameters follows. + +@table @option + +@item x, y, w, h +Specify a rectangular area where to limit the search for motion +vectors. +If desired the search for motion vectors can be limited to a +rectangular area of the frame defined by its top left corner, width +and height. These parameters have the same meaning as the drawbox +filter which can be used to visualise the position of the bounding +box. + +This is useful when simultaneous movement of subjects within the frame +might be confused for camera motion by the motion vector search. + +If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1 +then the full frame is used. This allows later options to be set +without specifying the bounding box for the motion vector search. + +Default - search the whole frame. + +@item rx, ry +Specify the maximum extent of movement in x and y directions in the +range 0-64 pixels. Default 16. + +@item edge +Specify how to generate pixels to fill blanks at the edge of the +frame. Available values are: +@table @samp +@item blank, 0 +Fill zeroes at blank locations +@item original, 1 +Original image at blank locations +@item clamp, 2 +Extruded edge value at blank locations +@item mirror, 3 +Mirrored edge at blank locations +@end table +Default value is @samp{mirror}. + +@item blocksize +Specify the blocksize to use for motion search. Range 4-128 pixels, +default 8. + +@item contrast +Specify the contrast threshold for blocks. Only blocks with more than +the specified contrast (difference between darkest and lightest +pixels) will be considered. Range 1-255, default 125. + +@item search +Specify the search strategy. Available values are: +@table @samp +@item exhaustive, 0 +Set exhaustive search +@item less, 1 +Set less exhaustive search. +@end table +Default value is @samp{exhaustive}. + +@item filename +If set then a detailed log of the motion search is written to the +specified file. + +@item opencl +If set to 1, specify using OpenCL capabilities, only available if +FFmpeg was configured with @code{--enable-opencl}. Default value is 0. + +@end table + +@section drawbox + +Draw a colored box on the input image. + +This filter accepts the following options: + +@table @option +@item x, y +Specify the top left corner coordinates of the box. Default to 0. + +@item width, w +@item height, h +Specify the width and height of the box, if 0 they are interpreted as +the input width and height. Default to 0. + +@item color, c +Specify the color of the box to write, it can be the name of a color +(case insensitive match) or a 0xRRGGBB[AA] sequence. If the special +value @code{invert} is used, the box edge color is the same as the +video with inverted luma. + +@item thickness, t +Set the thickness of the box edge. Default value is @code{4}. +@end table + +@subsection Examples + +@itemize +@item +Draw a black box around the edge of the input image: +@example +drawbox +@end example + +@item +Draw a box with color red and an opacity of 50%: +@example +drawbox=10:20:200:60:red@@0.5 +@end example + +The previous example can be specified as: +@example +drawbox=x=10:y=20:w=200:h=60:color=red@@0.5 +@end example + +@item +Fill the box with pink color: +@example +drawbox=x=10:y=10:w=100:h=100:color=pink@@0.5:t=max +@end example +@end itemize + +@anchor{drawtext} +@section drawtext + +Draw text string or text from specified file on top of video using the +libfreetype library. + +To enable compilation of this filter you need to configure FFmpeg with +@code{--enable-libfreetype}. + +@subsection Syntax + +The description of the accepted parameters follows. + +@table @option + +@item box +Used to draw a box around text using background color. +Value should be either 1 (enable) or 0 (disable). +The default value of @var{box} is 0. + +@item boxcolor +The color to be used for drawing box around text. +Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format +(e.g. "0xff00ff"), possibly followed by an alpha specifier. +The default value of @var{boxcolor} is "white". + +@item draw +Set an expression which specifies if the text should be drawn. If the +expression evaluates to 0, the text is not drawn. This is useful for +specifying that the text should be drawn only when specific conditions +are met. + +Default value is "1". + +See below for the list of accepted constants and functions. + +@item expansion +Select how the @var{text} is expanded. Can be either @code{none}, +@code{strftime} (deprecated) or +@code{normal} (default). See the @ref{drawtext_expansion, Text expansion} section +below for details. + +@item fix_bounds +If true, check and fix text coords to avoid clipping. + +@item fontcolor +The color to be used for drawing fonts. +Either a string (e.g. "red") or in 0xRRGGBB[AA] format +(e.g. "0xff000033"), possibly followed by an alpha specifier. +The default value of @var{fontcolor} is "black". + +@item fontfile +The font file to be used for drawing text. Path must be included. +This parameter is mandatory. + +@item fontsize +The font size to be used for drawing text. +The default value of @var{fontsize} is 16. + +@item ft_load_flags +Flags to be used for loading the fonts. + +The flags map the corresponding flags supported by libfreetype, and are +a combination of the following values: +@table @var +@item default +@item no_scale +@item no_hinting +@item render +@item no_bitmap +@item vertical_layout +@item force_autohint +@item crop_bitmap +@item pedantic +@item ignore_global_advance_width +@item no_recurse +@item ignore_transform +@item monochrome +@item linear_design +@item no_autohint +@item end table +@end table + +Default value is "render". + +For more information consult the documentation for the FT_LOAD_* +libfreetype flags. + +@item shadowcolor +The color to be used for drawing a shadow behind the drawn text. It +can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA] +form (e.g. "0xff00ff"), possibly followed by an alpha specifier. +The default value of @var{shadowcolor} is "black". + +@item shadowx, shadowy The x and y offsets for the text shadow position with respect to the position of the text. They can be either positive or negative values. Default value for both is "0". -@item shadowcolor -The color to be used for drawing a shadow behind the drawn text. It -can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA] -form (e.g. "0xff00ff"), possibly followed by an alpha specifier. -The default value of @var{shadowcolor} is "black". +@item tabsize +The size in number of spaces to use for rendering the tab. +Default value is 4. + +@item timecode +Set the initial timecode representation in "hh:mm:ss[:;.]ff" +format. It can be used with or without text parameter. @var{timecode_rate} +option must be specified. + +@item timecode_rate, rate, r +Set the timecode frame rate (timecode only). + +@item text +The text string to be drawn. The text must be a sequence of UTF-8 +encoded characters. +This parameter is mandatory if no file is specified with the parameter +@var{textfile}. + +@item textfile +A text file containing text to be drawn. The text must be a sequence +of UTF-8 encoded characters. + +This parameter is mandatory if no text string is specified with the +parameter @var{text}. + +If both @var{text} and @var{textfile} are specified, an error is thrown. + +@item reload +If set to 1, the @var{textfile} will be reloaded before each frame. +Be sure to update it atomically, or it may be read partially, or even fail. + +@item x, y +The expressions which specify the offsets where text will be drawn +within the video frame. They are relative to the top/left border of the +output image. + +The default value of @var{x} and @var{y} is "0". + +See below for the list of accepted constants and functions. +@end table + +The parameters for @var{x} and @var{y} are expressions containing the +following constants and functions: + +@table @option +@item dar +input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. + +@item line_h, lh +the height of each text line + +@item main_h, h, H +the input height + +@item main_w, w, W +the input width + +@item max_glyph_a, ascent +the maximum distance from the baseline to the highest/upper grid +coordinate used to place a glyph outline point, for all the rendered +glyphs. +It is a positive value, due to the grid's orientation with the Y axis +upwards. + +@item max_glyph_d, descent +the maximum distance from the baseline to the lowest grid coordinate +used to place a glyph outline point, for all the rendered glyphs. +This is a negative value, due to the grid's orientation, with the Y axis +upwards. + +@item max_glyph_h +maximum glyph height, that is the maximum height for all the glyphs +contained in the rendered text, it is equivalent to @var{ascent} - +@var{descent}. + +@item max_glyph_w +maximum glyph width, that is the maximum width for all the glyphs +contained in the rendered text + +@item n +the number of input frame, starting from 0 + +@item rand(min, max) +return a random number included between @var{min} and @var{max} + +@item sar +input sample aspect ratio + +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown + +@item text_h, th +the height of the rendered text + +@item text_w, tw +the width of the rendered text + +@item x, y +the x and y offset coordinates where the text is drawn. + +These parameters allow the @var{x} and @var{y} expressions to refer +each other, so you can for example specify @code{y=x/dar}. +@end table + +If libavfilter was built with @code{--enable-fontconfig}, then +@option{fontfile} can be a fontconfig pattern or omitted. + +@anchor{drawtext_expansion} +@subsection Text expansion + +If @option{expansion} is set to @code{strftime}, +the filter recognizes strftime() sequences in the provided text and +expands them accordingly. Check the documentation of strftime(). This +feature is deprecated. + +If @option{expansion} is set to @code{none}, the text is printed verbatim. + +If @option{expansion} is set to @code{normal} (which is the default), +the following expansion mechanism is used. + +The backslash character '\', followed by any character, always expands to +the second character. + +Sequence of the form @code{%@{...@}} are expanded. The text between the +braces is a function name, possibly followed by arguments separated by ':'. +If the arguments contain special characters or delimiters (':' or '@}'), +they should be escaped. + +Note that they probably must also be escaped as the value for the +@option{text} option in the filter argument string and as the filter +argument in the filtergraph description, and possibly also for the shell, +that makes up to four levels of escaping; using a text file avoids these +problems. + +The following functions are available: + +@table @command + +@item expr, e +The expression evaluation result. + +It must take one argument specifying the expression to be evaluated, +which accepts the same constants and functions as the @var{x} and +@var{y} values. Note that not all constants should be used, for +example the text size is not known when evaluating the expression, so +the constants @var{text_w} and @var{text_h} will have an undefined +value. + +@item gmtime +The time at which the filter is running, expressed in UTC. +It can accept an argument: a strftime() format string. + +@item localtime +The time at which the filter is running, expressed in the local time zone. +It can accept an argument: a strftime() format string. + +@item n, frame_num +The frame number, starting from 0. + +@item pts +The timestamp of the current frame, in seconds, with microsecond accuracy. + +@end table + +@subsection Examples + +@itemize +@item +Draw "Test Text" with font FreeSerif, using the default values for the +optional parameters. + +@example +drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'" +@end example + +@item +Draw 'Test Text' with font FreeSerif of size 24 at position x=100 +and y=50 (counting from the top-left corner of the screen), text is +yellow with a red box around it. Both the text and the box have an +opacity of 20%. + +@example +drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\ + x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2" +@end example + +Note that the double quotes are not necessary if spaces are not used +within the parameter list. + +@item +Show the text at the center of the video frame: +@example +drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2" +@end example + +@item +Show a text line sliding from right to left in the last row of the video +frame. The file @file{LONG_LINE} is assumed to contain a single line +with no newlines. +@example +drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t" +@end example + +@item +Show the content of file @file{CREDITS} off the bottom of the frame and scroll up. +@example +drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t" +@end example + +@item +Draw a single green letter "g", at the center of the input video. +The glyph baseline is placed at half screen height. +@example +drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent" +@end example + +@item +Show text for 1 second every 3 seconds: +@example +drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\,3)\,1):text='blink'" +@end example + +@item +Use fontconfig to set the font. Note that the colons need to be escaped. +@example +drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg' +@end example + +@item +Print the date of a real-time encoding (see strftime(3)): +@example +drawtext='fontfile=FreeSans.ttf:text=%@{localtime:%a %b %d %Y@}' +@end example + +@end itemize + +For more information about libfreetype, check: +@url{http://www.freetype.org/}. + +For more information about fontconfig, check: +@url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}. + +@section edgedetect + +Detect and draw edges. The filter uses the Canny Edge Detection algorithm. + +This filter accepts the following optional named parameters: + +@table @option +@item low, high +Set low and high threshold values used by the Canny thresholding +algorithm. + +The high threshold selects the "strong" edge pixels, which are then +connected through 8-connectivity with the "weak" edge pixels selected +by the low threshold. + +@var{low} and @var{high} threshold values must be choosen in the range +[0,1], and @var{low} should be lesser or equal to @var{high}. + +Default value for @var{low} is @code{20/255}, and default value for @var{high} +is @code{50/255}. +@end table + +Example: +@example +edgedetect=low=0.1:high=0.4 +@end example + +@section fade + +Apply fade-in/out effect to input video. + +This filter accepts the following options: + +@table @option +@item type, t +The effect type -- can be either "in" for fade-in, or "out" for a fade-out +effect. +Default is @code{in}. + +@item start_frame, s +Specify the number of the start frame for starting to apply the fade +effect. Default is 0. + +@item nb_frames, n +The number of frames for which the fade effect has to last. At the end of the +fade-in effect the output video will have the same intensity as the input video, +at the end of the fade-out transition the output video will be completely black. +Default is 25. + +@item alpha +If set to 1, fade only alpha channel, if one exists on the input. +Default value is 0. +@end table + +@subsection Examples + +@itemize +@item +Fade in first 30 frames of video: +@example +fade=in:0:30 +@end example + +The command above is equivalent to: +@example +fade=t=in:s=0:n=30 +@end example + +@item +Fade out last 45 frames of a 200-frame video: +@example +fade=out:155:45 +fade=type=out:start_frame=155:nb_frames=45 +@end example + +@item +Fade in first 25 frames and fade out last 25 frames of a 1000-frame video: +@example +fade=in:0:25, fade=out:975:25 +@end example + +@item +Make first 5 frames black, then fade in from frame 5-24: +@example +fade=in:5:20 +@end example + +@item +Fade in alpha over first 25 frames of video: +@example +fade=in:0:25:alpha=1 +@end example +@end itemize + +@section field + +Extract a single field from an interlaced image using stride +arithmetic to avoid wasting CPU time. The output frames are marked as +non-interlaced. + +This filter accepts the following named options: +@table @option +@item type +Specify whether to extract the top (if the value is @code{0} or +@code{top}) or the bottom field (if the value is @code{1} or +@code{bottom}). +@end table + +If the option key is not specified, the first value sets the @var{type} +option. For example: +@example +field=bottom +@end example + +is equivalent to: +@example +field=type=bottom +@end example + +@section fieldorder + +Transform the field order of the input video. + +This filter accepts the following options: + +@table @option + +@item order +Output field order. Valid values are @var{tff} for top field first or @var{bff} +for bottom field first. +@end table + +Default value is @samp{tff}. + +Transformation is achieved by shifting the picture content up or down +by one line, and filling the remaining line with appropriate picture content. +This method is consistent with most broadcast field order converters. + +If the input video is not flagged as being interlaced, or it is already +flagged as being of the required output field order then this filter does +not alter the incoming video. + +This filter is very useful when converting to or from PAL DV material, +which is bottom field first. + +For example: +@example +ffmpeg -i in.vob -vf "fieldorder=bff" out.dv +@end example + +@section fifo + +Buffer input images and send them when they are requested. + +This filter is mainly useful when auto-inserted by the libavfilter +framework. + +The filter does not take parameters. + +@anchor{format} +@section format + +Convert the input video to one of the specified pixel formats. +Libavfilter will try to pick one that is supported for the input to +the next filter. + +This filter accepts the following parameters: +@table @option + +@item pix_fmts +A '|'-separated list of pixel format names, for example +"pix_fmts=yuv420p|monow|rgb24". + +@end table + +@subsection Examples + +@itemize +@item +Convert the input video to the format @var{yuv420p} +@example +format=pix_fmts=yuv420p +@end example + +Convert the input video to any of the formats in the list +@example +format=pix_fmts=yuv420p|yuv444p|yuv410p +@end example +@end itemize + +@section fps + +Convert the video to specified constant frame rate by duplicating or dropping +frames as necessary. + +This filter accepts the following named parameters: +@table @option + +@item fps +Desired output frame rate. The default is @code{25}. + +@item round +Rounding method. + +Possible values are: +@table @option +@item zero +zero round towards 0 +@item inf +round away from 0 +@item down +round towards -infinity +@item up +round towards +infinity +@item near +round to nearest +@end table +The default is @code{near}. + +@end table + +Alternatively, the options can be specified as a flat string: +@var{fps}[:@var{round}]. + +See also the @ref{setpts} filter. + +@section framestep + +Select one frame every N. + +This filter accepts in input a string representing a positive +integer. Default argument is @code{1}. + +@anchor{frei0r} +@section frei0r + +Apply a frei0r effect to the input video. + +To enable compilation of this filter you need to install the frei0r +header and configure FFmpeg with @code{--enable-frei0r}. + +This filter accepts the following options: + +@table @option + +@item filter_name +The name to the frei0r effect to load. If the environment variable +@env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the +directories specified by the colon separated list in @env{FREIOR_PATH}, +otherwise in the standard frei0r paths, which are in this order: +@file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/}, +@file{/usr/lib/frei0r-1/}. + +@item filter_params +A '|'-separated list of parameters to pass to the frei0r effect. + +@end table + +A frei0r effect parameter can be a boolean (whose values are specified +with "y" and "n"), a double, a color (specified by the syntax +@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float +numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color +description), a position (specified by the syntax @var{X}/@var{Y}, +@var{X} and @var{Y} being float numbers) and a string. + +The number and kind of parameters depend on the loaded effect. If an +effect parameter is not specified the default value is set. + +@subsection Examples + +@itemize +@item +Apply the distort0r effect, set the first two double parameters: +@example +frei0r=filter_name=distort0r:filter_params=0.5|0.01 +@end example + +@item +Apply the colordistance effect, take a color as first parameter: +@example +frei0r=colordistance:0.2/0.3/0.4 +frei0r=colordistance:violet +frei0r=colordistance:0x112233 +@end example + +@item +Apply the perspective effect, specify the top left and top right image +positions: +@example +frei0r=perspective:0.2/0.2|0.8/0.2 +@end example +@end itemize + +For more information see: +@url{http://frei0r.dyne.org} + +@section geq + +The filter takes one, two, three or four equations as parameter, separated by ':'. +The first equation is mandatory and applies to the luma plane. The two +following are respectively for chroma blue and chroma red planes. + +The filter syntax allows named parameters: + +@table @option +@item lum_expr +the luminance expression +@item cb_expr +the chrominance blue expression +@item cr_expr +the chrominance red expression +@item alpha_expr +the alpha expression +@end table + +If one of the chrominance expression is not defined, it falls back on the other +one. If no alpha expression is specified it will evaluate to opaque value. +If none of chrominance expressions are +specified, they will evaluate the luminance expression. + +The expressions can use the following variables and functions: + +@table @option +@item N +The sequential number of the filtered frame, starting from @code{0}. + +@item X +@item Y +The coordinates of the current sample. + +@item W +@item H +The width and height of the image. + +@item SW +@item SH +Width and height scale depending on the currently filtered plane. It is the +ratio between the corresponding luma plane number of pixels and the current +plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and +@code{0.5,0.5} for chroma planes. + +@item T +Time of the current frame, expressed in seconds. + +@item p(x, y) +Return the value of the pixel at location (@var{x},@var{y}) of the current +plane. + +@item lum(x, y) +Return the value of the pixel at location (@var{x},@var{y}) of the luminance +plane. + +@item cb(x, y) +Return the value of the pixel at location (@var{x},@var{y}) of the +blue-difference chroma plane. Returns 0 if there is no such plane. + +@item cr(x, y) +Return the value of the pixel at location (@var{x},@var{y}) of the +red-difference chroma plane. Returns 0 if there is no such plane. + +@item alpha(x, y) +Return the value of the pixel at location (@var{x},@var{y}) of the alpha +plane. Returns 0 if there is no such plane. +@end table + +For functions, if @var{x} and @var{y} are outside the area, the value will be +automatically clipped to the closer edge. + +@subsection Examples + +@itemize +@item +Flip the image horizontally: +@example +geq=p(W-X\,Y) +@end example + +@item +Generate a bidimensional sine wave, with angle @code{PI/3} and a +wavelength of 100 pixels: +@example +geq=128 + 100*sin(2*(PI/100)*(cos(PI/3)*(X-50*T) + sin(PI/3)*Y)):128:128 +@end example + +@item +Generate a fancy enigmatic moving light: +@example +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 +@end example +@end itemize + +@section gradfun + +Fix the banding artifacts that are sometimes introduced into nearly flat +regions by truncation to 8bit color depth. +Interpolate the gradients that should go where the bands are, and +dither them. + +This filter is designed for playback only. Do not use it prior to +lossy compression, because compression tends to lose the dither and +bring back the bands. + +This filter accepts the following options: + +@table @option + +@item strength +The maximum amount by which the filter will change any one pixel. Also the +threshold for detecting nearly flat regions. Acceptable values range from .51 to +64, default value is 1.2, out-of-range values will be clipped to the valid +range. + +@item radius +The neighborhood to fit the gradient to. A larger radius makes for smoother +gradients, but also prevents the filter from modifying the pixels near detailed +regions. Acceptable values are 8-32, default value is 16, out-of-range values +will be clipped to the valid range. + +@end table + +Alternatively, the options can be specified as a flat string: +@var{strength}[:@var{radius}] + +@subsection Examples + +@itemize +@item +Apply the filter with a @code{3.5} strength and radius of @code{8}: +@example +gradfun=3.5:8 +@end example + +@item +Specify radius, omitting the strength (which will fall-back to the default +value): +@example +gradfun=radius=8 +@end example + +@end itemize + +@section hflip + +Flip the input video horizontally. + +For example to horizontally flip the input video with @command{ffmpeg}: +@example +ffmpeg -i in.avi -vf "hflip" out.avi +@end example + +@section histeq +This filter applies a global color histogram equalization on a +per-frame basis. + +It can be used to correct video that has a compressed range of pixel +intensities. The filter redistributes the pixel intensities to +equalize their distribution across the intensity range. It may be +viewed as an "automatically adjusting contrast filter". This filter is +useful only for correcting degraded or poorly captured source +video. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to syntax +@var{strength}:@var{intensity}:@var{antibanding}. + +This filter accepts the following named options: + +@table @option +@item strength +Determine the amount of equalization to be applied. As the strength +is reduced, the distribution of pixel intensities more-and-more +approaches that of the input frame. The value must be a float number +in the range [0,1] and defaults to 0.200. + +@item intensity +Set the maximum intensity that can generated and scale the output +values appropriately. The strength should be set as desired and then +the intensity can be limited if needed to avoid washing-out. The value +must be a float number in the range [0,1] and defaults to 0.210. + +@item antibanding +Set the antibanding level. If enabled the filter will randomly vary +the luminance of output pixels by a small amount to avoid banding of +the histogram. Possible values are @code{none}, @code{weak} or +@code{strong}. It defaults to @code{none}. +@end table + +@section histogram + +Compute and draw a color distribution histogram for the input video. + +The computed histogram is a representation of distribution of color components +in an image. + +The filter accepts the following named parameters: + +@table @option +@item mode +Set histogram mode. + +It accepts the following values: +@table @samp +@item levels +standard histogram that display color components distribution in an image. +Displays color graph for each color component. Shows distribution +of the Y, U, V, A or G, B, R components, depending on input format, +in current frame. Bellow each graph is color component scale meter. + +@item color +chroma values in vectorscope, if brighter more such chroma values are +distributed in an image. +Displays chroma values (U/V color placement) in two dimensional graph +(which is called a vectorscope). It can be used to read of the hue and +saturation of the current frame. At a same time it is a histogram. +The whiter a pixel in the vectorscope, the more pixels of the input frame +correspond to that pixel (that is the more pixels have this chroma value). +The V component is displayed on the horizontal (X) axis, with the leftmost +side being V = 0 and the rightmost side being V = 255. +The U component is displayed on the vertical (Y) axis, with the top +representing U = 0 and the bottom representing U = 255. + +The position of a white pixel in the graph corresponds to the chroma value +of a pixel of the input clip. So the graph can be used to read of the +hue (color flavor) and the saturation (the dominance of the hue in the color). +As the hue of a color changes, it moves around the square. At the center of +the square, the saturation is zero, which means that the corresponding pixel +has no color. If you increase the amount of a specific color, while leaving +the other colors unchanged, the saturation increases, and you move towards +the edge of the square. + +@item color2 +chroma values in vectorscope, similar as @code{color} but actual chroma values +are displayed. + +@item waveform +per row/column color component graph. In row mode graph in the left side represents +color component value 0 and right side represents value = 255. In column mode top +side represents color component value = 0 and bottom side represents value = 255. +@end table +Default value is @code{levels}. + +@item level_height +Set height of level in @code{levels}. Default value is @code{200}. +Allowed range is [50, 2048]. + +@item scale_height +Set height of color scale in @code{levels}. Default value is @code{12}. +Allowed range is [0, 40]. + +@item step +Set step for @code{waveform} mode. Smaller values are useful to find out how much +of same luminance values across input rows/columns are distributed. +Default value is @code{10}. Allowed range is [1, 255]. + +@item waveform_mode +Set mode for @code{waveform}. Can be either @code{row}, or @code{column}. +Default is @code{row}. + +@item display_mode +Set display mode for @code{waveform} and @code{levels}. +It accepts the following values: +@table @samp +@item parade +Display separate graph for the color components side by side in +@code{row} waveform mode or one below other in @code{column} waveform mode +for @code{waveform} histogram mode. For @code{levels} histogram mode +per color component graphs are placed one bellow other. + +This display mode in @code{waveform} histogram mode makes it easy to spot +color casts in the highlights and shadows of an image, by comparing the +contours of the top and the bottom of each waveform. +Since whites, grays, and blacks are characterized by +exactly equal amounts of red, green, and blue, neutral areas of the +picture should display three waveforms of roughly equal width/height. +If not, the correction is easy to make by making adjustments to level the +three waveforms. + +@item overlay +Presents information that's identical to that in the @code{parade}, except +that the graphs representing color components are superimposed directly +over one another. + +This display mode in @code{waveform} histogram mode can make it easier to spot +the relative differences or similarities in overlapping areas of the color +components that are supposed to be identical, such as neutral whites, grays, +or blacks. +@end table +Default is @code{parade}. +@end table + +@subsection Examples + +@itemize + +@item +Calculate and draw histogram: +@example +ffplay -i input -vf histogram +@end example + +@end itemize + +@section hqdn3d + +High precision/quality 3d denoise filter. This filter aims to reduce +image noise producing smooth images and making still images really +still. It should enhance compressibility. + +It accepts the following optional parameters: + +@table @option +@item luma_spatial +a non-negative float number which specifies spatial luma strength, +defaults to 4.0 + +@item chroma_spatial +a non-negative float number which specifies spatial chroma strength, +defaults to 3.0*@var{luma_spatial}/4.0 + +@item luma_tmp +a float number which specifies luma temporal strength, defaults to +6.0*@var{luma_spatial}/4.0 + +@item chroma_tmp +a float number which specifies chroma temporal strength, defaults to +@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial} +@end table + +@section hue + +Modify the hue and/or the saturation of the input. + +This filter accepts the following optional named options: + +@table @option +@item h +Specify the hue angle as a number of degrees. It accepts a float +number or an expression, and defaults to 0.0. + +@item H +Specify the hue angle as a number of radians. It accepts a float +number or an expression, and defaults to 0.0. + +@item s +Specify the saturation in the [-10,10] range. It accepts a float number and +defaults to 1.0. +@end table + +The @var{h}, @var{H} and @var{s} parameters are expressions containing the +following constants: + +@table @option +@item n +frame count of the input frame starting from 0 + +@item pts +presentation timestamp of the input frame expressed in time base units + +@item r +frame rate of the input video, NAN if the input frame rate is unknown + +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown + +@item tb +time base of the input video +@end table + +The options can also be set using the syntax: @var{hue}:@var{saturation} + +In this case @var{hue} is expressed in degrees. + +@subsection Examples + +@itemize +@item +Set the hue to 90 degrees and the saturation to 1.0: +@example +hue=h=90:s=1 +@end example + +@item +Same command but expressing the hue in radians: +@example +hue=H=PI/2:s=1 +@end example + +@item +Same command without named options, hue must be expressed in degrees: +@example +hue=90:1 +@end example + +@item +Note that "h:s" syntax does not support expressions for the values of +h and s, so the following example will issue an error: +@example +hue=PI/2:1 +@end example + +@item +Rotate hue and make the saturation swing between 0 +and 2 over a period of 1 second: +@example +hue="H=2*PI*t: s=sin(2*PI*t)+1" +@end example + +@item +Apply a 3 seconds saturation fade-in effect starting at 0: +@example +hue="s=min(t/3\,1)" +@end example + +The general fade-in expression can be written as: +@example +hue="s=min(0\, max((t-START)/DURATION\, 1))" +@end example + +@item +Apply a 3 seconds saturation fade-out effect starting at 5 seconds: +@example +hue="s=max(0\, min(1\, (8-t)/3))" +@end example + +The general fade-out expression can be written as: +@example +hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))" +@end example + +@end itemize + +@subsection Commands + +This filter supports the following command: +@table @option +@item reinit +Modify the hue and/or the saturation of the input video. +The command accepts the same named options and syntax than when calling the +filter from the command-line. + +If a parameter is omitted, it is kept at its current value. +@end table + +@section idet + +Detect video interlacing type. + +This filter tries to detect if the input is interlaced or progressive, +top or bottom field first. + +@section il + +Deinterleave or interleave fields. + +This filter allows to process interlaced images fields without +deinterlacing them. Deinterleaving splits the input frame into 2 +fields (so called half pictures). Odd lines are moved to the top +half of the output image, even lines to the bottom half. +You can process (filter) them independently and then re-interleave them. + +It accepts a list of options in the form of @var{key}=@var{value} pairs +separated by ":". A description of the accepted options follows. + +@table @option +@item luma_mode, l +@item chroma_mode, s +@item alpha_mode, a +Available values for @var{luma_mode}, @var{chroma_mode} and +@var{alpha_mode} are: + +@table @samp +@item none +Do nothing. + +@item deinterleave, d +Deinterleave fields, placing one above the other. + +@item interleave, i +Interleave fields. Reverse the effect of deinterleaving. +@end table +Default value is @code{none}. + +@item luma_swap, ls +@item chroma_swap, cs +@item alpha_swap, as +Swap luma/chroma/alpha fields. Exchange even & odd lines. Default value is @code{0}. +@end table + +@section kerndeint + +Deinterlace input video by applying Donald Graft's adaptive kernel +deinterling. Work on interlaced parts of a video to produce +progressive frames. + +This filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the following syntax: +@var{thresh}:@var{map}:@var{order}:@var{sharp}:@var{twoway}. + +The description of the accepted parameters follows. + +@table @option +@item thresh +Set the threshold which affects the filter's tolerance when +determining if a pixel line must be processed. It must be an integer +in the range [0,255] and defaults to 10. A value of 0 will result in +applying the process on every pixels. + +@item map +Paint pixels exceeding the threshold value to white if set to 1. +Default is 0. + +@item order +Set the fields order. Swap fields if set to 1, leave fields alone if +0. Default is 0. + +@item sharp +Enable additional sharpening if set to 1. Default is 0. + +@item twoway +Enable twoway sharpening if set to 1. Default is 0. +@end table + +@subsection Examples + +@itemize +@item +Apply default values: +@example +kerndeint=thresh=10:map=0:order=0:sharp=0:twoway=0 +@end example + +@item +Enable additional sharpening: +@example +kerndeint=sharp=1 +@end example + +@item +Paint processed pixels in white: +@example +kerndeint=map=1 +@end example +@end itemize + +@section lut, lutrgb, lutyuv + +Compute a look-up table for binding each pixel component input value +to an output value, and apply it to input video. + +@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb} +to an RGB input video. + +These filters accept in input a ":"-separated list of options, which +specify the expressions used for computing the lookup table for the +corresponding pixel component values. + +The @var{lut} filter requires either YUV or RGB pixel formats in +input, and accepts the options: +@table @option +@item c0 +set first pixel component expression +@item c1 +set second pixel component expression +@item c2 +set third pixel component expression +@item c3 +set fourth pixel component expression, corresponds to the alpha component +@end table + +The exact component associated to each option depends on the format in +input. + +The @var{lutrgb} filter requires RGB pixel formats in input, and +accepts the options: +@table @option +@item r +set red component expression +@item g +set green component expression +@item b +set blue component expression +@item a +alpha component expression +@end table + +The @var{lutyuv} filter requires YUV pixel formats in input, and +accepts the options: +@table @option +@item y +set Y/luminance component expression +@item u +set U/Cb component expression +@item v +set V/Cr component expression +@item a +set alpha component expression +@end table + +The expressions can contain the following constants and functions: + +@table @option +@item w, h +the input width and height + +@item val +input value for the pixel component + +@item clipval +the input value clipped in the @var{minval}-@var{maxval} range + +@item maxval +maximum value for the pixel component + +@item minval +minimum value for the pixel component + +@item negval +the negated value for the pixel component value clipped in the +@var{minval}-@var{maxval} range , it corresponds to the expression +"maxval-clipval+minval" + +@item clip(val) +the computed value in @var{val} clipped in the +@var{minval}-@var{maxval} range + +@item gammaval(gamma) +the computed gamma correction value of the pixel component value +clipped in the @var{minval}-@var{maxval} range, corresponds to the +expression +"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval" + +@end table + +All expressions default to "val". + +@subsection Examples + +@itemize +@item +Negate input video: +@example +lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val" +lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val" +@end example + +The above is the same as: +@example +lutrgb="r=negval:g=negval:b=negval" +lutyuv="y=negval:u=negval:v=negval" +@end example + +@item +Negate luminance: +@example +lutyuv=y=negval +@end example + +@item +Remove chroma components, turns the video into a graytone image: +@example +lutyuv="u=128:v=128" +@end example + +@item +Apply a luma burning effect: +@example +lutyuv="y=2*val" +@end example + +@item +Remove green and blue components: +@example +lutrgb="g=0:b=0" +@end example + +@item +Set a constant alpha channel value on input: +@example +format=rgba,lutrgb=a="maxval-minval/2" +@end example + +@item +Correct luminance gamma by a 0.5 factor: +@example +lutyuv=y=gammaval(0.5) +@end example + +@item +Discard least significant bits of luma: +@example +lutyuv=y='bitand(val, 128+64+32)' +@end example +@end itemize + +@section mp + +Apply an MPlayer filter to the input video. + +This filter provides a wrapper around most of the filters of +MPlayer/MEncoder. + +This wrapper is considered experimental. Some of the wrapped filters +may not work properly and we may drop support for them, as they will +be implemented natively into FFmpeg. Thus you should avoid +depending on them when writing portable scripts. + +The filters accepts the parameters: +@var{filter_name}[:=]@var{filter_params} + +@var{filter_name} is the name of a supported MPlayer filter, +@var{filter_params} is a string containing the parameters accepted by +the named filter. + +The list of the currently supported filters follows: +@table @var +@item detc +@item dint +@item divtc +@item down3dright +@item eq2 +@item eq +@item fil +@item fspp +@item ilpack +@item ivtc +@item mcdeint +@item ow +@item perspective +@item phase +@item pp7 +@item pullup +@item qp +@item sab +@item softpulldown +@item spp +@item telecine +@item tinterlace +@item uspp +@end table + +The parameter syntax and behavior for the listed filters are the same +of the corresponding MPlayer filters. For detailed instructions check +the "VIDEO FILTERS" section in the MPlayer manual. + +@subsection Examples + +@itemize +@item +Adjust gamma, brightness, contrast: +@example +mp=eq2=1.0:2:0.5 +@end example +@end itemize + +See also mplayer(1), @url{http://www.mplayerhq.hu/}. + +@section negate + +Negate input video. + +This filter accepts an integer in input, if non-zero it negates the +alpha component (if available). The default value in input is 0. + +@section noformat + +Force libavfilter not to use any of the specified pixel formats for the +input to the next filter. + +This filter accepts the following parameters: +@table @option + +@item pix_fmts +A '|'-separated list of pixel format names, for example +"pix_fmts=yuv420p|monow|rgb24". + +@end table + +@subsection Examples + +@itemize +@item +Force libavfilter to use a format different from @var{yuv420p} for the +input to the vflip filter: +@example +noformat=pix_fmts=yuv420p,vflip +@end example + +@item +Convert the input video to any of the formats not contained in the list: +@example +noformat=yuv420p|yuv444p|yuv410p +@end example +@end itemize + +@section noise + +Add noise on video input frame. + +This filter accepts a list of options in the form of @var{key}=@var{value} +pairs separated by ":". A description of the accepted options follows. + +@table @option +@item all_seed +@item c0_seed +@item c1_seed +@item c2_seed +@item c3_seed +Set noise seed for specific pixel component or all pixel components in case +of @var{all_seed}. Default value is @code{123457}. + +@item all_strength, alls +@item c0_strength, c0s +@item c1_strength, c1s +@item c2_strength, c2s +@item c3_strength, c3s +Set noise strength for specific pixel component or all pixel components in case +@var{all_strength}. Default value is @code{0}. Allowed range is [0, 100]. + +@item all_flags, allf +@item c0_flags, c0f +@item c1_flags, c1f +@item c2_flags, c2f +@item c3_flags, c3f +Set pixel component flags or set flags for all components if @var{all_flags}. +Available values for component flags are: +@table @samp +@item a +averaged temporal noise (smoother) +@item p +mix random noise with a (semi)regular pattern +@item q +higher quality (slightly better looking, slightly slower) +@item t +temporal noise (noise pattern changes between frames) +@item u +uniform noise (gaussian otherwise) +@end table +@end table + +@subsection Examples + +Add temporal and uniform noise to input video: +@example +noise=alls=20:allf=t+u +@end example + +@section null + +Pass the video source unchanged to the output. + +@section ocv + +Apply video transform using libopencv. + +To enable this filter install libopencv library and headers and +configure FFmpeg with @code{--enable-libopencv}. + +This filter accepts the following parameters: + +@table @option + +@item filter_name +The name of the libopencv filter to apply. + +@item filter_params +The parameters to pass to the libopencv filter. If not specified the default +values are assumed. + +@end table + +Refer to the official libopencv documentation for more precise +information: +@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} + +Follows the list of supported libopencv filters. + +@anchor{dilate} +@subsection dilate + +Dilate an image by using a specific structuring element. +This filter corresponds to the libopencv function @code{cvDilate}. + +It accepts the parameters: @var{struct_el}|@var{nb_iterations}. + +@var{struct_el} represents a structuring element, and has the syntax: +@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape} + +@var{cols} and @var{rows} represent the number of columns and rows of +the structuring element, @var{anchor_x} and @var{anchor_y} the anchor +point, and @var{shape} the shape for the structuring element, and +can be one of the values "rect", "cross", "ellipse", "custom". + +If the value for @var{shape} is "custom", it must be followed by a +string of the form "=@var{filename}". The file with name +@var{filename} is assumed to represent a binary image, with each +printable character corresponding to a bright pixel. When a custom +@var{shape} is used, @var{cols} and @var{rows} are ignored, the number +or columns and rows of the read file are assumed instead. + +The default value for @var{struct_el} is "3x3+0x0/rect". + +@var{nb_iterations} specifies the number of times the transform is +applied to the image, and defaults to 1. + +Follow some example: +@example +# use the default values +ocv=dilate + +# dilate using a structuring element with a 5x5 cross, iterate two times +ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2 + +# read the shape from the file diamond.shape, iterate two times +# the file diamond.shape may contain a pattern of characters like this: +# * +# *** +# ***** +# *** +# * +# the specified cols and rows are ignored (but not the anchor point coordinates) +ocv=dilate:0x0+2x2/custom=diamond.shape|2 +@end example + +@subsection erode + +Erode an image by using a specific structuring element. +This filter corresponds to the libopencv function @code{cvErode}. + +The filter accepts the parameters: @var{struct_el}:@var{nb_iterations}, +with the same syntax and semantics as the @ref{dilate} filter. + +@subsection smooth + +Smooth the input video. + +The filter takes the following parameters: +@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}. + +@var{type} is the type of smooth filter to apply, and can be one of +the following values: "blur", "blur_no_scale", "median", "gaussian", +"bilateral". The default value is "gaussian". + +@var{param1}, @var{param2}, @var{param3}, and @var{param4} are +parameters whose meanings depend on smooth type. @var{param1} and +@var{param2} accept integer positive values or 0, @var{param3} and +@var{param4} accept float values. + +The default value for @var{param1} is 3, the default value for the +other parameters is 0. + +These parameters correspond to the parameters assigned to the +libopencv function @code{cvSmooth}. + +@anchor{overlay} +@section overlay + +Overlay one video on top of another. + +It takes two inputs and one output, the first input is the "main" +video on which the second input is overlayed. + +This filter accepts a list of @var{key}=@var{value} pairs as argument, +separated by ":". If the key of the first options is omitted, the +arguments are interpreted according to the syntax @var{x}:@var{y}. + +A description of the accepted options follows. + +@table @option +@item x +@item y +Set the expression for the x and y coordinates of the overlayed video +on the main video. Default value is "0" for both expressions. In case +the expression is invalid, it is set to a huge value (meaning that the +overlay will not be displayed within the output visible area). + +@item enable +Set the expression which enables the overlay. If the evaluation is +different from 0, the overlay is displayed on top of the input +frame. By default it is "1". + +@item eval +Set when the expressions for @option{x}, @option{y}, and +@option{enable} are evaluated. + +It accepts the following values: +@table @samp +@item init +only evaluate expressions once during the filter initialization or +when a command is processed + +@item frame +evaluate expressions for each incoming frame +@end table + +Default value is @samp{frame}. + +@item shortest +If set to 1, force the output to terminate when the shortest input +terminates. Default value is 0. + +@item format +Set the format for the output video. + +It accepts the following values: +@table @samp +@item yuv420 +force YUV420 output + +@item yuv444 +force YUV444 output + +@item rgb +force RGB output +@end table + +Default value is @samp{yuv420}. + +@item rgb @emph{(deprecated)} +If set to 1, force the filter to accept inputs in the RGB +color space. Default value is 0. This option is deprecated, use +@option{format} instead. +@end table + +The @option{x}, @option{y}, and @option{enable} expressions can +contain the following parameters. + +@table @option +@item main_w, W +@item main_h, H +main input width and height + +@item overlay_w, w +@item overlay_h, h +overlay input width and height + +@item x +@item y +the computed values for @var{x} and @var{y}. They are evaluated for +each new frame. + +@item hsub +@item vsub +horizontal and vertical chroma subsample values of the output +format. For example for the pixel format "yuv422p" @var{hsub} is 2 and +@var{vsub} is 1. + +@item n +the number of input frame, starting from 0 + +@item pos +the position in the file of the input frame, NAN if unknown + +@item t +timestamp expressed in seconds, NAN if the input timestamp is unknown +@end table + +Note that the @var{n}, @var{pos}, @var{t} variables are available only +when evaluation is done @emph{per frame}, and will evaluate to NAN +when @option{eval} is set to @samp{init}. + +Be aware that frames are taken from each input video in timestamp +order, hence, if their initial timestamps differ, it is a a good idea +to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to +have them begin in the same zero timestamp, as it does the example for +the @var{movie} filter. + +You can chain together more overlays but you should test the +efficiency of such approach. + +@subsection Commands + +This filter supports the following command: +@table @option +@item x +Set the @option{x} option expression. + +@item y +Set the @option{y} option expression. + +@item enable +Set the @option{enable} option expression. +@end table + +@subsection Examples + +@itemize +@item +Draw the overlay at 10 pixels from the bottom right corner of the main +video: +@example +overlay=main_w-overlay_w-10:main_h-overlay_h-10 +@end example + +Using named options the example above becomes: +@example +overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10 +@end example + +@item +Insert a transparent PNG logo in the bottom left corner of the input, +using the @command{ffmpeg} tool with the @code{-filter_complex} option: +@example +ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output +@end example + +@item +Insert 2 different transparent PNG logos (second logo on bottom +right corner) using the @command{ffmpeg} tool: +@example +ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output +@end example + +@item +Add a transparent color layer on top of the main video, @code{WxH} +must specify the size of the main input to the overlay filter: +@example +color=color=red@@.3:size=WxH [over]; [in][over] overlay [out] +@end example + +@item +Play an original video and a filtered version (here with the deshake +filter) side by side using the @command{ffplay} tool: +@example +ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w' +@end example + +The above command is the same as: +@example +ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w' +@end example + +@item +Make a sliding overlay appearing from the left to the right top part of the +screen starting since time 2: +@example +overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0 +@end example + +@item +Compose output by putting two input videos side to side: +@example +ffmpeg -i left.avi -i right.avi -filter_complex " +nullsrc=size=200x100 [background]; +[0:v] setpts=PTS-STARTPTS, scale=100x100 [left]; +[1:v] setpts=PTS-STARTPTS, scale=100x100 [right]; +[background][left] overlay=shortest=1 [background+left]; +[background+left][right] overlay=shortest=1:x=100 [left+right] +" +@end example + +@item +Chain several overlays in cascade: +@example +nullsrc=s=200x200 [bg]; +testsrc=s=100x100, split=4 [in0][in1][in2][in3]; +[in0] lutrgb=r=0, [bg] overlay=0:0 [mid0]; +[in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1]; +[in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2]; +[in3] null, [mid2] overlay=100:100 [out0] +@end example + +@end itemize + +@section pad + +Add paddings to the input image, and place the original input at the +given coordinates @var{x}, @var{y}. + +The filter accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". + +If the key of the first options is omitted, the arguments are +interpreted according to the syntax +@var{width}:@var{height}:@var{x}:@var{y}:@var{color}. + +A description of the accepted options follows. + +@table @option +@item width, w +@item height, h +Specify an expression for the size of the output image with the +paddings added. If the value for @var{width} or @var{height} is 0, the +corresponding input size is used for the output. + +The @var{width} expression can reference the value set by the +@var{height} expression, and vice versa. + +The default value of @var{width} and @var{height} is 0. + +@item x +@item y +Specify an expression for the offsets where to place the input image +in the padded area with respect to the top/left border of the output +image. + +The @var{x} expression can reference the value set by the @var{y} +expression, and vice versa. + +The default value of @var{x} and @var{y} is 0. + +@item color +Specify the color of the padded area, it can be the name of a color +(case insensitive match) or a 0xRRGGBB[AA] sequence. + +The default value of @var{color} is "black". +@end table + +The value for the @var{width}, @var{height}, @var{x}, and @var{y} +options are expressions containing the following constants: + +@table @option +@item in_w, in_h +the input video width and height + +@item iw, ih +same as @var{in_w} and @var{in_h} + +@item out_w, out_h +the output width and height, that is the size of the padded area as +specified by the @var{width} and @var{height} expressions + +@item ow, oh +same as @var{out_w} and @var{out_h} + +@item x, y +x and y offsets as specified by the @var{x} and @var{y} +expressions, or NAN if not yet specified + +@item a +same as @var{iw} / @var{ih} + +@item sar +input sample aspect ratio + +@item dar +input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@end table + +@subsection Examples + +@itemize +@item +Add paddings with color "violet" to the input video. Output video +size is 640x480, the top-left corner of the input video is placed at +column 0, row 40: +@example +pad=640:480:0:40:violet +@end example + +The example above is equivalent to the following command: +@example +pad=width=640:height=480:x=0:y=40:color=violet +@end example + +@item +Pad the input to get an output with dimensions increased by 3/2, +and put the input video at the center of the padded area: +@example +pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2" +@end example + +@item +Pad the input to get a squared output with size equal to the maximum +value between the input width and height, and put the input video at +the center of the padded area: +@example +pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2" +@end example + +@item +Pad the input to get a final w/h ratio of 16:9: +@example +pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2" +@end example + +@item +In case of anamorphic video, in order to set the output display aspect +correctly, it is necessary to use @var{sar} in the expression, +according to the relation: +@example +(ih * X / ih) * sar = output_dar +X = output_dar / sar +@end example + +Thus the previous example needs to be modified to: +@example +pad="ih*16/9/sar:ih:(ow-iw)/2:(oh-ih)/2" +@end example + +@item +Double output size and put the input video in the bottom-right +corner of the output padded area: +@example +pad="2*iw:2*ih:ow-iw:oh-ih" +@end example +@end itemize + +@section pixdesctest + +Pixel format descriptor test filter, mainly useful for internal +testing. The output video should be equal to the input video. + +For example: +@example +format=monow, pixdesctest +@end example + +can be used to test the monowhite pixel format descriptor definition. + +@section pp + +Enable the specified chain of postprocessing subfilters using libpostproc. This +library should be automatically selected with a GPL build (@code{--enable-gpl}). +Subfilters must be separated by '/' and can be disabled by prepending a '-'. +Each subfilter and some options have a short and a long name that can be used +interchangeably, i.e. dr/dering are the same. + +All subfilters share common options to determine their scope: + +@table @option +@item a/autoq +Honor the quality commands for this subfilter. + +@item c/chrom +Do chrominance filtering, too (default). + +@item y/nochrom +Do luminance filtering only (no chrominance). + +@item n/noluma +Do chrominance filtering only (no luminance). +@end table + +These options can be appended after the subfilter name, separated by a ':'. + +Available subfilters are: + +@table @option +@item hb/hdeblock[:difference[:flatness]] +Horizontal deblocking filter +@table @option +@item difference +Difference factor where higher values mean more deblocking (default: @code{32}). +@item flatness +Flatness threshold where lower values mean more deblocking (default: @code{39}). +@end table + +@item vb/vdeblock[:difference[:flatness]] +Vertical deblocking filter +@table @option +@item difference +Difference factor where higher values mean more deblocking (default: @code{32}). +@item flatness +Flatness threshold where lower values mean more deblocking (default: @code{39}). +@end table + +@item ha/hadeblock[:difference[:flatness]] +Accurate horizontal deblocking filter +@table @option +@item difference +Difference factor where higher values mean more deblocking (default: @code{32}). +@item flatness +Flatness threshold where lower values mean more deblocking (default: @code{39}). +@end table + +@item va/vadeblock[:difference[:flatness]] +Accurate vertical deblocking filter +@table @option +@item difference +Difference factor where higher values mean more deblocking (default: @code{32}). +@item flatness +Flatness threshold where lower values mean more deblocking (default: @code{39}). +@end table +@end table + +The horizontal and vertical deblocking filters share the difference and +flatness values so you cannot set different horizontal and vertical +thresholds. + +@table @option +@item h1/x1hdeblock +Experimental horizontal deblocking filter + +@item v1/x1vdeblock +Experimental vertical deblocking filter + +@item dr/dering +Deringing filter + +@item tn/tmpnoise[:threshold1[:threshold2[:threshold3]]], temporal noise reducer +@table @option +@item threshold1 +larger -> stronger filtering +@item threshold2 +larger -> stronger filtering +@item threshold3 +larger -> stronger filtering +@end table + +@item al/autolevels[:f/fullyrange], automatic brightness / contrast correction +@table @option +@item f/fullyrange +Stretch luminance to @code{0-255}. +@end table + +@item lb/linblenddeint +Linear blend deinterlacing filter that deinterlaces the given block by +filtering all lines with a @code{(1 2 1)} filter. + +@item li/linipoldeint +Linear interpolating deinterlacing filter that deinterlaces the given block by +linearly interpolating every second line. + +@item ci/cubicipoldeint +Cubic interpolating deinterlacing filter deinterlaces the given block by +cubically interpolating every second line. + +@item md/mediandeint +Median deinterlacing filter that deinterlaces the given block by applying a +median filter to every second line. + +@item fd/ffmpegdeint +FFmpeg deinterlacing filter that deinterlaces the given block by filtering every +second line with a @code{(-1 4 2 4 -1)} filter. + +@item l5/lowpass5 +Vertically applied FIR lowpass deinterlacing filter that deinterlaces the given +block by filtering all lines with a @code{(-1 2 6 2 -1)} filter. + +@item fq/forceQuant[:quantizer] +Overrides the quantizer table from the input with the constant quantizer you +specify. +@table @option +@item quantizer +Quantizer to use +@end table + +@item de/default +Default pp filter combination (@code{hb:a,vb:a,dr:a}) + +@item fa/fast +Fast pp filter combination (@code{h1:a,v1:a,dr:a}) + +@item ac +High quality pp filter combination (@code{ha:a:128:7,va:a,dr:a}) +@end table + +@subsection Examples + +@itemize +@item +Apply horizontal and vertical deblocking, deringing and automatic +brightness/contrast: +@example +pp=hb/vb/dr/al +@end example + +@item +Apply default filters without brightness/contrast correction: +@example +pp=de/-al +@end example + +@item +Apply default filters and temporal denoiser: +@example +pp=default/tmpnoise:1:2:3 +@end example + +@item +Apply deblocking on luminance only, and switch vertical deblocking on or off +automatically depending on available CPU time: +@example +pp=hb:y/vb:a +@end example +@end itemize + +@section removelogo + +Suppress a TV station logo, using an image file to determine which +pixels comprise the logo. It works by filling in the pixels that +comprise the logo with neighboring pixels. + +This filter requires one argument which specifies the filter bitmap +file, which can be any image format supported by libavformat. The +width and height of the image file must match those of the video +stream being processed. + +Pixels in the provided bitmap image with a value of zero are not +considered part of the logo, non-zero pixels are considered part of +the logo. If you use white (255) for the logo and black (0) for the +rest, you will be safe. For making the filter bitmap, it is +recommended to take a screen capture of a black frame with the logo +visible, and then using a threshold filter followed by the erode +filter once or twice. + +If needed, little splotches can be fixed manually. Remember that if +logo pixels are not covered, the filter quality will be much +reduced. Marking too many pixels as part of the logo does not hurt as +much, but it will increase the amount of blurring needed to cover over +the image and will destroy more information than necessary, and extra +pixels will slow things down on a large logo. + +@section scale + +Scale (resize) the input video, using the libswscale library. + +The scale filter forces the output display aspect ratio to be the same +of the input, by changing the output sample aspect ratio. + +This filter accepts a list of named options in the form of +@var{key}=@var{value} pairs separated by ":". If the key for the first +two options is not specified, the assumed keys for the first two +values are @code{w} and @code{h}. If the first option has no key and +can be interpreted like a video size specification, it will be used +to set the video size. + +A description of the accepted options follows. + +@table @option +@item width, w +Output video width. +default value is @code{iw}. See below +for the list of accepted constants. + +@item height, h +Output video height. +default value is @code{ih}. +See below for the list of accepted constants. + +@item interl +Set the interlacing. It accepts the following values: + +@table @option +@item 1 +force interlaced aware scaling + +@item 0 +do not apply interlaced scaling + +@item -1 +select interlaced aware scaling depending on whether the source frames +are flagged as interlaced or not +@end table + +Default value is @code{0}. + +@item flags +Set libswscale scaling flags. If not explictly specified the filter +applies a bilinear scaling algorithm. + +@item size, s +Set the video size, the value must be a valid abbreviation or in the +form @var{width}x@var{height}. +@end table + +The values of the @var{w} and @var{h} options are expressions +containing the following constants: + +@table @option +@item in_w, in_h +the input width and height + +@item iw, ih +same as @var{in_w} and @var{in_h} + +@item out_w, out_h +the output (cropped) width and height + +@item ow, oh +same as @var{out_w} and @var{out_h} + +@item a +same as @var{iw} / @var{ih} + +@item sar +input sample aspect ratio + +@item dar +input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar} + +@item hsub, vsub +horizontal and vertical chroma subsample values. For example for the +pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@end table + +If the input image format is different from the format requested by +the next filter, the scale filter will convert the input to the +requested format. + +If the value for @var{w} or @var{h} is 0, the respective input +size is used for the output. + +If the value for @var{w} or @var{h} is -1, the scale filter will use, for the +respective output size, a value that maintains the aspect ratio of the input +image. + +@subsection Examples + +@itemize +@item +Scale the input video to a size of 200x100: +@example +scale=w=200:h=100 +@end example + +This is equivalent to: +@example +scale=w=200:h=100 +@end example + +or: +@example +scale=200x100 +@end example + +@item +Specify a size abbreviation for the output size: +@example +scale=qcif +@end example + +which can also be written as: +@example +scale=size=qcif +@end example + +@item +Scale the input to 2x: +@example +scale=w=2*iw:h=2*ih +@end example + +@item +The above is the same as: +@example +scale=2*in_w:2*in_h +@end example + +@item +Scale the input to 2x with forced interlaced scaling: +@example +scale=2*iw:2*ih:interl=1 +@end example + +@item +Scale the input to half size: +@example +scale=w=iw/2:h=ih/2 +@end example + +@item +Increase the width, and set the height to the same size: +@example +scale=3/2*iw:ow +@end example + +@item +Seek for Greek harmony: +@example +scale=iw:1/PHI*iw +scale=ih*PHI:ih +@end example + +@item +Increase the height, and set the width to 3/2 of the height: +@example +scale=w=3/2*oh:h=3/5*ih +@end example + +@item +Increase the size, but make the size a multiple of the chroma +subsample values: +@example +scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub" +@end example + +@item +Increase the width to a maximum of 500 pixels, keep the same input +aspect ratio: +@example +scale=w='min(500\, iw*3/2):h=-1' +@end example +@end itemize + +@section separatefields + +The @code{separatefields} takes a frame-based video input and splits +each frame into its components fields, producing a new half height clip +with twice the frame rate and twice the frame count. + +This filter use field-dominance information in frame to decide which +of each pair of fields to place first in the output. +If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter. + +@section setdar, setsar + +The @code{setdar} filter sets the Display Aspect Ratio for the filter +output video. -@item ft_load_flags -Flags to be used for loading the fonts. +This is done by changing the specified Sample (aka Pixel) Aspect +Ratio, according to the following equation: +@example +@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR} +@end example -The flags map the corresponding flags supported by libfreetype, and are -a combination of the following values: -@table @var -@item default -@item no_scale -@item no_hinting -@item render -@item no_bitmap -@item vertical_layout -@item force_autohint -@item crop_bitmap -@item pedantic -@item ignore_global_advance_width -@item no_recurse -@item ignore_transform -@item monochrome -@item linear_design -@item no_autohint -@item end table -@end table +Keep in mind that the @code{setdar} filter does not modify the pixel +dimensions of the video frame. Also the display aspect ratio set by +this filter may be changed by later filters in the filterchain, +e.g. in case of scaling or if another "setdar" or a "setsar" filter is +applied. -Default value is "render". +The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for +the filter output video. -For more information consult the documentation for the FT_LOAD_* -libfreetype flags. +Note that as a consequence of the application of this filter, the +output display aspect ratio will change according to the equation +above. -@item tabsize -The size in number of spaces to use for rendering the tab. -Default value is 4. +Keep in mind that the sample aspect ratio set by the @code{setsar} +filter may be changed by later filters in the filterchain, e.g. if +another "setsar" or a "setdar" filter is applied. -@item fix_bounds -If true, check and fix text coords to avoid clipping. +The @code{setdar} and @code{setsar} filters accept a string in the +form @var{num}:@var{den} expressing an aspect ratio, or the following +named options, expressed as a sequence of @var{key}=@var{value} pairs, +separated by ":". + +@table @option +@item max +Set the maximum integer value to use for expressing numerator and +denominator when reducing the expressed aspect ratio to a rational. +Default value is @code{100}. + +@item r, ratio, dar, sar: +Set the aspect ratio used by the filter. + +The parameter can be a floating point number string, an expression, or +a string of the form @var{num}:@var{den}, where @var{num} and +@var{den} are the numerator and denominator of the aspect ratio. If +the parameter is not specified, it is assumed the value "0". +In case the form "@var{num}:@var{den}" the @code{:} character should +be escaped. @end table -For example the command: +If the keys are omitted in the named options list, the specifed values +are assumed to be @var{ratio} and @var{max} in that order. + +For example to change the display aspect ratio to 16:9, specify: @example -drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'" +setdar='16:9' +# the above is equivalent to +setdar=1.77777 +setdar=dar=16/9 +setdar=dar=1.77777 @end example -will draw "Test Text" with font FreeSerif, using the default values -for the optional parameters. +To change the sample aspect ratio to 10:11, specify: +@example +setsar='10:11' +# the above is equivalent to +setsar='sar=10/11' +@end example -The command: +To set a display aspect ratio of 16:9, and specify a maximum integer value of +1000 in the aspect ratio reduction, use the command: @example -drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\ - x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2" +setdar=ratio='16:9':max=1000 @end example -will draw 'Test Text' with font FreeSerif of size 24 at position x=100 -and y=50 (counting from the top-left corner of the screen), text is -yellow with a red box around it. Both the text and the box have an -opacity of 20%. +@anchor{setfield} +@section setfield -Note that the double quotes are not necessary if spaces are not used -within the parameter list. +Force field for the output video frame. -For more information about libfreetype, check: -@url{http://www.freetype.org/}. +The @code{setfield} filter marks the interlace type field for the +output frames. It does not change the input frame, but only sets the +corresponding property, which affects how the frame is treated by +following filters (e.g. @code{fieldorder} or @code{yadif}). -@section fade +This filter accepts a single option @option{mode}, which can be +specified either by setting @code{mode=VALUE} or setting the value +alone. Available values are: -Apply fade-in/out effect to input video. +@table @samp +@item auto +Keep the same field property. -This filter accepts the following options: +@item bff +Mark the frame as bottom-field-first. + +@item tff +Mark the frame as top-field-first. + +@item prog +Mark the frame as progressive. +@end table + +@section showinfo + +Show a line containing various information for each input video frame. +The input video is not modified. + +The shown line contains a sequence of key/value pairs of the form +@var{key}:@var{value}. + +A description of each shown parameter follows: @table @option +@item n +sequential number of the input frame, starting from 0 + +@item pts +Presentation TimeStamp of the input frame, expressed as a number of +time base units. The time base unit depends on the filter input pad. + +@item pts_time +Presentation TimeStamp of the input frame, expressed as a number of +seconds + +@item pos +position of the frame in the input stream, -1 if this information in +unavailable and/or meaningless (for example in case of synthetic video) + +@item fmt +pixel format name + +@item sar +sample aspect ratio of the input frame, expressed in the form +@var{num}/@var{den} + +@item s +size of the input frame, expressed in the form +@var{width}x@var{height} + +@item i +interlaced mode ("P" for "progressive", "T" for top field first, "B" +for bottom field first) + +@item iskey +1 if the frame is a key frame, 0 otherwise @item type -The effect type -- can be either "in" for fade-in, or "out" for a fade-out -effect. +picture type of the input frame ("I" for an I-frame, "P" for a +P-frame, "B" for a B-frame, "?" for unknown type). +Check also the documentation of the @code{AVPictureType} enum and of +the @code{av_get_picture_type_char} function defined in +@file{libavutil/avutil.h}. + +@item checksum +Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame -@item start_frame -The number of the start frame for starting to apply the fade effect. +@item plane_checksum +Adler-32 checksum (printed in hexadecimal) of each plane of the input frame, +expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]" +@end table -@item nb_frames -The number of frames for which the fade effect has to last. At the end of the -fade-in effect the output video will have the same intensity as the input video, -at the end of the fade-out transition the output video will be completely black. +@section smartblur + +Blur the input video without impacting the outlines. +This filter accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". + +If the key of the first options is omitted, the arguments are +interpreted according to the syntax: +@var{luma_radius}:@var{luma_strength}:@var{luma_threshold}[:@var{chroma_radius}:@var{chroma_strength}:@var{chroma_threshold}] + +A description of the accepted options follows. + +@table @option +@item luma_radius, lr +@item chroma_radius, cr +Set the luma/chroma radius. The option value must be a float number in +the range [0.1,5.0] that specifies the variance of the gaussian filter +used to blur the image (slower if larger). Default value is 1.0. + +@item luma_strength, ls +@item chroma_strength, cs +Set the luma/chroma strength. The option value must be a float number +in the range [-1.0,1.0] that configures the blurring. A value included +in [0.0,1.0] will blur the image whereas a value included in +[-1.0,0.0] will sharpen the image. Default value is 1.0. + +@item luma_threshold, lt +@item chroma_threshold, ct +Set the luma/chroma threshold used as a coefficient to determine +whether a pixel should be blurred or not. The option value must be an +integer in the range [-30,30]. A value of 0 will filter all the image, +a value included in [0,30] will filter flat areas and a value included +in [-30,0] will filter edges. Default value is 0. @end table -A few usage examples follow, usable too as test scenarios. -@example -# fade in first 30 frames of video -fade=type=in:nb_frames=30 +If a chroma option is not explicitly set, the corresponding luma value +is set. -# fade out last 45 frames of a 200-frame video -fade=type=out:start_frame=155:nb_frames=45 +@section stereo3d -# fade in first 25 frames and fade out last 25 frames of a 1000-frame video -fade=type=in:start_frame=0:nb_frames=25, fade=type=out:start_frame=975:nb_frames=25 +Convert between different stereoscopic image formats. -# make first 5 frames black, then fade in from frame 5-24 -fade=type=in:start_frame=5:nb_frames=20 -@end example +This filter accepts the following named options, expressed as a +sequence of @var{key}=@var{value} pairs, separated by ":". -@section fieldorder +@table @option +@item in +Set stereoscopic image format of input. -Transform the field order of the input video. +Available values for input image formats are: +@table @samp +@item sbsl +side by side parallel (left eye left, right eye right) -This filter accepts the following options: +@item sbsr +side by side crosseye (right eye left, left eye right) + +@item sbs2l +side by side parallel with half width resolution +(left eye left, right eye right) + +@item sbs2r +side by side crosseye with half width resolution +(right eye left, left eye right) + +@item abl +above-below (left eye above, right eye below) + +@item abr +above-below (right eye above, left eye below) + +@item ab2l +above-below with half height resolution +(left eye above, right eye below) + +@item ab2r +above-below with half height resolution +(right eye above, left eye below) + +Default value is @samp{sbsl}. +@end table + +@item out +Set stereoscopic image format of output. + +Available values for output image formats are all the input formats as well as: +@table @samp +@item arbg +anaglyph red/blue gray +(red filter on left eye, blue filter on right eye) + +@item argg +anaglyph red/green gray +(red filter on left eye, green filter on right eye) + +@item arcg +anaglyph red/cyan gray +(red filter on left eye, cyan filter on right eye) + +@item arch +anaglyph red/cyan half colored +(red filter on left eye, cyan filter on right eye) + +@item arcc +anaglyph red/cyan color +(red filter on left eye, cyan filter on right eye) + +@item arcd +anaglyph red/cyan color optimized with the least squares projection of dubois +(red filter on left eye, cyan filter on right eye) + +@item agmg +anaglyph green/magenta gray +(green filter on left eye, magenta filter on right eye) + +@item agmh +anaglyph green/magenta half colored +(green filter on left eye, magenta filter on right eye) + +@item agmc +anaglyph green/magenta colored +(green filter on left eye, magenta filter on right eye) + +@item agmd +anaglyph green/magenta color optimized with the least squares projection of dubois +(green filter on left eye, magenta filter on right eye) + +@item aybg +anaglyph yellow/blue gray +(yellow filter on left eye, blue filter on right eye) + +@item aybh +anaglyph yellow/blue half colored +(yellow filter on left eye, blue filter on right eye) + +@item aybc +anaglyph yellow/blue colored +(yellow filter on left eye, blue filter on right eye) + +@item aybd +anaglyph yellow/blue color optimized with the least squares projection of dubois +(yellow filter on left eye, blue filter on right eye) + +@item irl +interleaved rows (left eye has top row, right eye starts on next row) + +@item irr +interleaved rows (right eye has top row, left eye starts on next row) + +@item ml +mono output (left eye only) + +@item mr +mono output (right eye only) +@end table + +Default value is @samp{arcd}. +@end table + +@anchor{subtitles} +@section subtitles + +Draw subtitles on top of input video using the libass library. + +To enable compilation of this filter you need to configure FFmpeg with +@code{--enable-libass}. This filter also requires a build with libavcodec and +libavformat to convert the passed subtitles file to ASS (Advanced Substation +Alpha) subtitles format. + +This filter accepts the following named options, expressed as a +sequence of @var{key}=@var{value} pairs, separated by ":". @table @option +@item filename, f +Set the filename of the subtitle file to read. It must be specified. -@item order -Output field order. Valid values are @var{tff} for top field first or @var{bff} -for bottom field first. +@item original_size +Specify the size of the original video, the video for which the ASS file +was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is +necessary to correctly scale the fonts if the aspect ratio has been changed. + +@item charenc +Set subtitles input character encoding. @code{subtitles} filter only. Only +useful if not UTF-8. @end table -Default value is "tff". +If the first key is not specified, it is assumed that the first value +specifies the @option{filename}. -Transformation is achieved by shifting the picture content up or down -by one line, and filling the remaining line with appropriate picture content. -This method is consistent with most broadcast field order converters. +For example, to render the file @file{sub.srt} on top of the input +video, use the command: +@example +subtitles=sub.srt +@end example -If the input video is not flagged as being interlaced, or it is already -flagged as being of the required output field order then this filter does -not alter the incoming video. +which is equivalent to: +@example +subtitles=filename=sub.srt +@end example -This filter is very useful when converting to or from PAL DV material, -which is bottom field first. +@section split + +Split input video into several identical outputs. + +The filter accepts a single parameter which specifies the number of outputs. If +unspecified, it defaults to 2. + +For example +@example +ffmpeg -i INPUT -filter_complex split=5 OUTPUT +@end example +will create 5 copies of the input video. For example: @example -./avconv -i in.vob -vf "fieldorder=order=bff" out.dv +[in] split [splitout1][splitout2]; +[splitout1] crop=100:100:0:0 [cropout]; +[splitout2] pad=200:200:100:100 [padout]; @end example -@section fifo +will create two separate outputs from the same input, one cropped and +one padded. -Buffer input images and send them when they are requested. +@section super2xsai -This filter is mainly useful when auto-inserted by the libavfilter -framework. +Scale the input by 2x and smooth using the Super2xSaI (Scale and +Interpolate) pixel art scaling algorithm. -The filter does not take parameters. +Useful for enlarging pixel art images without reducing sharpness. -@section format +@section swapuv +Swap U & V plane. -Convert the input video to one of the specified pixel formats. -Libavfilter will try to pick one that is supported for the input to -the next filter. +@section thumbnail +Select the most representative frame in a given sequence of consecutive frames. + +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to the syntax +thumbnail[=@var{n}]. -This filter accepts the following parameters: @table @option +@item n +Set the frames batch size to analyze; in a set of @var{n} frames, the filter +will pick one of them, and then handle the next batch of @var{n} frames until +the end. Default is @code{100}. +@end table -@item pix_fmts -A '|'-separated list of pixel format names, for example -"pix_fmts=yuv420p|monow|rgb24". +Since the filter keeps track of the whole frames sequence, a bigger @var{n} +value will result in a higher memory usage, so a high value is not recommended. + +@subsection Examples + +@itemize +@item +Extract one picture each 50 frames: +@example +thumbnail=50 +@end example + +@item +Complete example of a thumbnail creation with @command{ffmpeg}: +@example +ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png +@end example +@end itemize + +@section tile + +Tile several successive frames together. + +It accepts a list of options in the form of @var{key}=@var{value} pairs +separated by ":". A description of the accepted options follows. + +@table @option + +@item layout +Set the grid size (i.e. the number of lines and columns) in the form +"@var{w}x@var{h}". + +@item margin +Set the outer border margin in pixels. + +@item padding +Set the inner border thickness (i.e. the number of pixels between frames). For +more advanced padding options (such as having different values for the edges), +refer to the pad video filter. + +@item nb_frames +Set the maximum number of frames to render in the given area. It must be less +than or equal to @var{w}x@var{h}. The default value is @code{0}, meaning all +the area will be used. @end table -Some examples follow: +Alternatively, the options can be specified as a flat string: + +@var{layout}[:@var{nb_frames}[:@var{margin}[:@var{padding}]]] + +For example, produce 8x8 PNG tiles of all keyframes (@option{-skip_frame +nokey}) in a movie: @example -# convert the input video to the format "yuv420p" -format=pix_fmts=yuv420p +ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png +@end example +The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from +duplicating each output frame to accomodate the originally detected frame +rate. -# convert the input video to any of the formats in the list -format=pix_fmts=yuv420p|yuv444p|yuv410p +Another example to display @code{5} pictures in an area of @code{3x2} frames, +with @code{7} pixels between them, and @code{2} pixels of initial margin, using +mixed flat and named options: +@example +tile=3x2:nb_frames=5:padding=7:margin=2 @end example -@section fps +@section tinterlace -Convert the video to specified constant framerate by duplicating or dropping -frames as necessary. +Perform various types of temporal field interlacing. + +Frames are counted starting from 1, so the first input frame is +considered odd. + +This filter accepts options in the form of @var{key}=@var{value} pairs +separated by ":". +Alternatively, the @var{mode} option can be specified as a value alone, +optionally followed by a ":" and further ":" separated @var{key}=@var{value} +pairs. + +A description of the accepted options follows. -This filter accepts the following named parameters: @table @option -@item fps -Desired output framerate. +@item mode +Specify the mode of the interlacing. This option can also be specified +as a value alone. See below for a list of values for this option. + +Available values are: + +@table @samp +@item merge, 0 +Move odd frames into the upper field, even into the lower field, +generating a double height frame at half frame rate. + +@item drop_odd, 1 +Only output even frames, odd frames are dropped, generating a frame with +unchanged height at half frame rate. + +@item drop_even, 2 +Only output odd frames, even frames are dropped, generating a frame with +unchanged height at half frame rate. + +@item pad, 3 +Expand each frame to full height, but pad alternate lines with black, +generating a frame with double height at the same input frame rate. + +@item interleave_top, 4 +Interleave the upper field from odd frames with the lower field from +even frames, generating a frame with unchanged height at half frame rate. + +@item interleave_bottom, 5 +Interleave the lower field from odd frames with the upper field from +even frames, generating a frame with unchanged height at half frame rate. + +@item interlacex2, 6 +Double frame rate with unchanged height. Frames are inserted each +containing the second temporal field from the previous input frame and +the first temporal field from the next input frame. This mode relies on +the top_field_first flag. Useful for interlaced video displays with no +field synchronisation. +@end table + +Numeric values are deprecated but are accepted for backward +compatibility reasons. + +Default mode is @code{merge}. + +@item flags +Specify flags influencing the filter process. + +Available value for @var{flags} is: + +@table @option +@item low_pass_filter, vlfp +Enable vertical low-pass filtering in the filter. +Vertical low-pass filtering is required when creating an interlaced +destination from a progressive source which contains high-frequency +vertical detail. Filtering will reduce interlace 'twitter' and Moire +patterning. + +Vertical low-pass filtering can only be enabled for @option{mode} +@var{interleave_top} and @var{interleave_bottom}. +@end table @end table -@anchor{frei0r} -@section frei0r - -Apply a frei0r effect to the input video. +@section transpose -To enable compilation of this filter you need to install the frei0r -header and configure Libav with --enable-frei0r. +Transpose rows with columns in the input video and optionally flip it. -This filter accepts the following options: +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ':'. If the key of the first options is omitted, +the arguments are interpreted according to the syntax +@var{dir}:@var{passthrough}. @table @option +@item dir +Specify the transposition direction. Can assume the following values: -@item filter_name -The name to the frei0r effect to load. If the environment variable -@env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the -directories specified by the colon separated list in @env{FREIOR_PATH}, -otherwise in the standard frei0r paths, which are in this order: -@file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/}, -@file{/usr/lib/frei0r-1/}. +@table @samp +@item 0, 4 +Rotate by 90 degrees counterclockwise and vertically flip (default), that is: +@example +L.R L.l +. . -> . . +l.r R.r +@end example -@item filter_params -A '|'-separated list of parameters to pass to the frei0r effect. +@item 1, 5 +Rotate by 90 degrees clockwise, that is: +@example +L.R l.L +. . -> . . +l.r r.R +@end example + +@item 2, 6 +Rotate by 90 degrees counterclockwise, that is: +@example +L.R R.r +. . -> . . +l.r L.l +@end example +@item 3, 7 +Rotate by 90 degrees clockwise and vertically flip, that is: +@example +L.R r.R +. . -> . . +l.r l.L +@end example @end table -A frei0r effect parameter can be a boolean (whose values are specified -with "y" and "n"), a double, a color (specified by the syntax -@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float -numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color -description), a position (specified by the syntax @var{X}/@var{Y}, -@var{X} and @var{Y} being float numbers) and a string. +For values between 4-7, the transposition is only done if the input +video geometry is portrait and not landscape. These values are +deprecated, the @code{passthrough} option should be used instead. -The number and kind of parameters depend on the loaded effect. If an -effect parameter is not specified the default value is set. +@item passthrough +Do not apply the transposition if the input geometry matches the one +specified by the specified value. It accepts the following values: +@table @samp +@item none +Always apply transposition. +@item portrait +Preserve portrait geometry (when @var{height} >= @var{width}). +@item landscape +Preserve landscape geometry (when @var{width} >= @var{height}). +@end table -Some examples follow: -@example -# apply the distort0r effect, set the first two double parameters -frei0r=filter_name=distort0r:filter_params=0.5|0.01 +Default value is @code{none}. +@end table -# apply the colordistance effect, takes a color as first parameter -frei0r=colordistance:0.2/0.3/0.4 -frei0r=colordistance:violet -frei0r=colordistance:0x112233 +For example to rotate by 90 degrees clockwise and preserve portrait +layout: +@example +transpose=dir=1:passthrough=portrait +@end example -# apply the perspective effect, specify the top left and top right -# image positions -frei0r=perspective:0.2/0.2|0.8/0.2 +The command above can also be specified as: +@example +transpose=1:portrait @end example -For more information see: -@url{http://piksel.org/frei0r} +@section unsharp -@section gradfun +Sharpen or blur the input video. -Fix the banding artifacts that are sometimes introduced into nearly flat -regions by truncation to 8bit colordepth. -Interpolate the gradients that should go where the bands are, and -dither them. +This filter accepts parameters as a list of @var{key}=@var{value} pairs, +separated by ":". -This filter is designed for playback only. Do not use it prior to -lossy compression, because compression tends to lose the dither and -bring back the bands. +If the key of the first options is omitted, the arguments are +interpreted according to the syntax: +@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount} -This filter accepts the following options: +A description of the accepted options follows. @table @option - -@item strength -The maximum amount by which the filter will change any one pixel. Also the -threshold for detecting nearly flat regions. Acceptable values range from .51 to -64, default value is 1.2, out-of-range values will be clipped to the valid -range. - -@item radius -The neighborhood to fit the gradient to. A larger radius makes for smoother -gradients, but also prevents the filter from modifying the pixels near detailed -regions. Acceptable values are 8-32, default value is 16, out-of-range values -will be clipped to the valid range. - +@item luma_msize_x, lx +@item chroma_msize_x, cx +Set the luma/chroma matrix horizontal size. It must be an odd integer +between 3 and 63, default value is 5. + +@item luma_msize_y, ly +@item chroma_msize_y, cy +Set the luma/chroma matrix vertical size. It must be an odd integer +between 3 and 63, default value is 5. + +@item luma_amount, la +@item chroma_amount, ca +Set the luma/chroma effect strength. It can be a float number, +reasonable values lay between -1.5 and 1.5. + +Negative values will blur the input video, while positive values will +sharpen it, a value of zero will disable the effect. + +Default value is 1.0 for @option{luma_amount}, 0.0 for +@option{chroma_amount}. @end table +@subsection Examples + +@itemize +@item +Apply strong luma sharpen effect: @example -# default parameters -gradfun=strength=1.2:radius=16 +unsharp=7:7:2.5 +@end example -# omitting radius -gradfun=1.2 +@item +Apply strong blur of both luma and chroma parameters: +@example +unsharp=7:7:-2:7:7:-2 @end example +@end itemize -@section hflip +@section vflip -Flip the input video horizontally. +Flip the input video vertically. -For example to horizontally flip the input video with @command{avconv}: @example -avconv -i in.avi -vf "hflip" out.avi +ffmpeg -i in.avi -vf "vflip" out.avi @end example -@section hqdn3d - -High precision/quality 3d denoise filter. This filter aims to reduce -image noise producing smooth images and making still images really -still. It should enhance compressibility. +@section yadif -It accepts the following optional parameters: +Deinterlace the input video ("yadif" means "yet another deinterlacing +filter"). -@table @option -@item luma_spatial -a non-negative float number which specifies spatial luma strength, -defaults to 4.0 +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". If the key of the first options is omitted, +the arguments are interpreted according to syntax +@var{mode}:@var{parity}:@var{deint}. -@item chroma_spatial -a non-negative float number which specifies spatial chroma strength, -defaults to 3.0*@var{luma_spatial}/4.0 +The description of the accepted parameters follows. -@item luma_tmp -a float number which specifies luma temporal strength, defaults to -6.0*@var{luma_spatial}/4.0 +@table @option +@item mode +Specify the interlacing mode to adopt. Accept one of the following +values: -@item chroma_tmp -a float number which specifies chroma temporal strength, defaults to -@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial} +@table @option +@item 0, send_frame +output 1 frame for each frame +@item 1, send_field +output 1 frame for each field +@item 2, send_frame_nospatial +like @code{send_frame} but skip spatial interlacing check +@item 3, send_field_nospatial +like @code{send_field} but skip spatial interlacing check @end table -@section lut, lutrgb, lutyuv - -Compute a look-up table for binding each pixel component input value -to an output value, and apply it to input video. - -@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb} -to an RGB input video. +Default value is @code{send_frame}. -These filters accept in input a ":"-separated list of options, which -specify the expressions used for computing the lookup table for the -corresponding pixel component values. +@item parity +Specify the picture field parity assumed for the input interlaced +video. Accept one of the following values: -The @var{lut} filter requires either YUV or RGB pixel formats in -input, and accepts the options: @table @option -@item @var{c0} (first pixel component) -@item @var{c1} (second pixel component) -@item @var{c2} (third pixel component) -@item @var{c3} (fourth pixel component, corresponds to the alpha component) +@item 0, tff +assume top field first +@item 1, bff +assume bottom field first +@item -1, auto +enable automatic detection @end table -The exact component associated to each option depends on the format in -input. +Default value is @code{auto}. +If interlacing is unknown or decoder does not export this information, +top field first will be assumed. + +@item deint +Specify which frames to deinterlace. Accept one of the following +values: -The @var{lutrgb} filter requires RGB pixel formats in input, and -accepts the options: @table @option -@item @var{r} (red component) -@item @var{g} (green component) -@item @var{b} (blue component) -@item @var{a} (alpha component) +@item 0, all +deinterlace all frames +@item 1, interlaced +only deinterlace frames marked as interlaced @end table -The @var{lutyuv} filter requires YUV pixel formats in input, and -accepts the options: -@table @option -@item @var{y} (Y/luminance component) -@item @var{u} (U/Cb component) -@item @var{v} (V/Cr component) -@item @var{a} (alpha component) +Default value is @code{all}. @end table -The expressions can contain the following constants and functions: +@c man end VIDEO FILTERS -@table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), PHI (golden ratio) +@chapter Video Sources +@c man begin VIDEO SOURCES -@item w, h -the input width and height +Below is a description of the currently available video sources. -@item val -input value for the pixel component +@section buffer -@item clipval -the input value clipped in the @var{minval}-@var{maxval} range +Buffer video frames, and make them available to the filter chain. -@item maxval -maximum value for the pixel component +This source is mainly intended for a programmatic use, in particular +through the interface defined in @file{libavfilter/vsrc_buffer.h}. -@item minval -minimum value for the pixel component +It accepts a list of options in the form of @var{key}=@var{value} pairs +separated by ":". A description of the accepted options follows. -@item negval -the negated value for the pixel component value clipped in the -@var{minval}-@var{maxval} range , it corresponds to the expression -"maxval-clipval+minval" +@table @option -@item clip(val) -the computed value in @var{val} clipped in the -@var{minval}-@var{maxval} range +@item video_size +Specify the size (width and height) of the buffered video frames. -@item gammaval(gamma) -the computed gamma correction value of the pixel component value -clipped in the @var{minval}-@var{maxval} range, corresponds to the -expression -"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval" +@item pix_fmt +A string representing the pixel format of the buffered video frames. +It may be a number corresponding to a pixel format, or a pixel format +name. + +@item time_base +Specify the timebase assumed by the timestamps of the buffered frames. + +@item time_base +Specify the frame rate expected for the video stream. + +@item pixel_aspect +Specify the sample aspect ratio assumed by the video frames. +@item sws_param +Specify the optional parameters to be used for the scale filter which +is automatically inserted when an input change is detected in the +input size or format. @end table -All expressions default to "val". +For example: +@example +buffer=size=320x240:pix_fmt=yuv410p:time_base=1/24:pixel_aspect=1/1 +@end example -Some examples follow: +will instruct the source to accept video frames with size 320x240 and +with format "yuv410p", assuming 1/24 as the timestamps timebase and +square pixels (1:1 sample aspect ratio). +Since the pixel format with name "yuv410p" corresponds to the number 6 +(check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}), +this example corresponds to: @example -# negate input video -lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val" -lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val" +buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1 +@end example -# the above is the same as -lutrgb="r=negval:g=negval:b=negval" -lutyuv="y=negval:u=negval:v=negval" +Alternatively, the options can be specified as a flat string, but this +syntax is deprecated: -# negate luminance -lutyuv=negval +@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}] -# remove chroma components, turns the video into a graytone image -lutyuv="u=128:v=128" +@section cellauto -# apply a luma burning effect -lutyuv="y=2*val" +Create a pattern generated by an elementary cellular automaton. -# remove green and blue components -lutrgb="g=0:b=0" +The initial state of the cellular automaton can be defined through the +@option{filename}, and @option{pattern} options. If such options are +not specified an initial state is created randomly. -# set a constant alpha channel value on input -format=rgba,lutrgb=a="maxval-minval/2" +At each new frame a new row in the video is filled with the result of +the cellular automaton next generation. The behavior when the whole +frame is filled is defined by the @option{scroll} option. -# correct luminance gamma by a 0.5 factor -lutyuv=y=gammaval(0.5) -@end example +This source accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. -@section negate +@table @option +@item filename, f +Read the initial cellular automaton state, i.e. the starting row, from +the specified file. +In the file, each non-whitespace character is considered an alive +cell, a newline will terminate the row, and further characters in the +file will be ignored. -Negate input video. +@item pattern, p +Read the initial cellular automaton state, i.e. the starting row, from +the specified string. -This filter accepts an integer in input, if non-zero it negates the -alpha component (if available). The default value in input is 0. +Each non-whitespace character in the string is considered an alive +cell, a newline will terminate the row, and further characters in the +string will be ignored. -@section noformat +@item rate, r +Set the video rate, that is the number of frames generated per second. +Default is 25. -Force libavfilter not to use any of the specified pixel formats for the -input to the next filter. +@item random_fill_ratio, ratio +Set the random fill ratio for the initial cellular automaton row. It +is a floating point number value ranging from 0 to 1, defaults to +1/PHI. -This filter accepts the following parameters: -@table @option +This option is ignored when a file or a pattern is specified. -@item pix_fmts -A '|'-separated list of pixel format names, for example -"pix_fmts=yuv420p|monow|rgb24". +@item random_seed, seed +Set the seed for filling randomly the initial row, must be an integer +included between 0 and UINT32_MAX. If not specified, or if explicitly +set to -1, the filter will try to use a good random seed on a best +effort basis. + +@item rule +Set the cellular automaton rule, it is a number ranging from 0 to 255. +Default value is 110. + +@item size, s +Set the size of the output video. + +If @option{filename} or @option{pattern} is specified, the size is set +by default to the width of the specified initial state row, and the +height is set to @var{width} * PHI. + +If @option{size} is set, it must contain the width of the specified +pattern string, and the specified pattern will be centered in the +larger row. + +If a filename or a pattern string is not specified, the size value +defaults to "320x518" (used for a randomly generated initial state). +@item scroll +If set to 1, scroll the output upward when all the rows in the output +have been already filled. If set to 0, the new generated row will be +written over the top row just after the bottom row is filled. +Defaults to 1. + +@item start_full, full +If set to 1, completely fill the output with generated rows before +outputting the first frame. +This is the default behavior, for disabling set the value to 0. + +@item stitch +If set to 1, stitch the left and right row edges together. +This is the default behavior, for disabling set the value to 0. @end table -Some examples follow: +@subsection Examples + +@itemize +@item +Read the initial state from @file{pattern}, and specify an output of +size 200x400. @example -# force libavfilter to use a format different from "yuv420p" for the -# input to the vflip filter -noformat=pix_fmts=yuv420p,vflip +cellauto=f=pattern:s=200x400 +@end example -# convert the input video to any of the formats not contained in the list -noformat=yuv420p|yuv444p|yuv410p +@item +Generate a random initial row with a width of 200 cells, with a fill +ratio of 2/3: +@example +cellauto=ratio=2/3:s=200x200 @end example -@section null +@item +Create a pattern generated by rule 18 starting by a single alive cell +centered on an initial row with width 100: +@example +cellauto=p=@@:s=100x400:full=0:rule=18 +@end example -Pass the video source unchanged to the output. +@item +Specify a more elaborated initial pattern: +@example +cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18 +@end example -@section ocv +@end itemize -Apply video transform using libopencv. +@section mandelbrot -To enable this filter install libopencv library and headers and -configure Libav with --enable-libopencv. +Generate a Mandelbrot set fractal, and progressively zoom towards the +point specified with @var{start_x} and @var{start_y}. -This filter accepts the following parameters: +This source accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. @table @option -@item filter_name -The name of the libopencv filter to apply. +@item end_pts +Set the terminal pts value. Default value is 400. -@item filter_params -The parameters to pass to the libopencv filter. If not specified the default -values are assumed. +@item end_scale +Set the terminal scale value. +Must be a floating point value. Default value is 0.3. + +@item inner +Set the inner coloring mode, that is the algorithm used to draw the +Mandelbrot fractal internal region. +It shall assume one of the following values: +@table @option +@item black +Set black mode. +@item convergence +Show time until convergence. +@item mincol +Set color based on point closest to the origin of the iterations. +@item period +Set period mode. @end table -Refer to the official libopencv documentation for more precise -information: -@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} +Default value is @var{mincol}. -Follows the list of supported libopencv filters. +@item bailout +Set the bailout value. Default value is 10.0. -@anchor{dilate} -@subsection dilate +@item maxiter +Set the maximum of iterations performed by the rendering +algorithm. Default value is 7189. -Dilate an image by using a specific structuring element. -This filter corresponds to the libopencv function @code{cvDilate}. +@item outer +Set outer coloring mode. +It shall assume one of following values: +@table @option +@item iteration_count +Set iteration cound mode. +@item normalized_iteration_count +set normalized iteration count mode. +@end table +Default value is @var{normalized_iteration_count}. -It accepts the parameters: @var{struct_el}|@var{nb_iterations}. +@item rate, r +Set frame rate, expressed as number of frames per second. Default +value is "25". -@var{struct_el} represents a structuring element, and has the syntax: -@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape} +@item size, s +Set frame size. Default value is "640x480". -@var{cols} and @var{rows} represent the number of columns and rows of -the structuring element, @var{anchor_x} and @var{anchor_y} the anchor -point, and @var{shape} the shape for the structuring element, and -can be one of the values "rect", "cross", "ellipse", "custom". +@item start_scale +Set the initial scale value. Default value is 3.0. -If the value for @var{shape} is "custom", it must be followed by a -string of the form "=@var{filename}". The file with name -@var{filename} is assumed to represent a binary image, with each -printable character corresponding to a bright pixel. When a custom -@var{shape} is used, @var{cols} and @var{rows} are ignored, the number -or columns and rows of the read file are assumed instead. +@item start_x +Set the initial x position. Must be a floating point value between +-100 and 100. Default value is -0.743643887037158704752191506114774. -The default value for @var{struct_el} is "3x3+0x0/rect". +@item start_y +Set the initial y position. Must be a floating point value between +-100 and 100. Default value is -0.131825904205311970493132056385139. +@end table -@var{nb_iterations} specifies the number of times the transform is -applied to the image, and defaults to 1. +@section mptestsrc -Follow some example: -@example -# use the default values -ocv=dilate +Generate various test patterns, as generated by the MPlayer test filter. -# dilate using a structuring element with a 5x5 cross, iterate two times -ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2 +The size of the generated video is fixed, and is 256x256. +This source is useful in particular for testing encoding features. -# read the shape from the file diamond.shape, iterate two times -# the file diamond.shape may contain a pattern of characters like this: -# * -# *** -# ***** -# *** -# * -# the specified cols and rows are ignored (but not the anchor point coordinates) -ocv=dilate:0x0+2x2/custom=diamond.shape|2 -@end example +This source accepts an optional sequence of @var{key}=@var{value} pairs, +separated by ":". The description of the accepted options follows. -@subsection erode +@table @option -Erode an image by using a specific structuring element. -This filter corresponds to the libopencv function @code{cvErode}. +@item rate, r +Specify the frame rate of the sourced video, as the number of frames +generated per second. It has to be a string in the format +@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float +number or a valid video frame rate abbreviation. The default value is +"25". -The filter accepts the parameters: @var{struct_el}:@var{nb_iterations}, -with the same syntax and semantics as the @ref{dilate} filter. +@item duration, d +Set the video duration of the sourced video. The accepted syntax is: +@example +[-]HH:MM:SS[.m...] +[-]S+[.m...] +@end example +See also the function @code{av_parse_time()}. -@subsection smooth +If not specified, or the expressed duration is negative, the video is +supposed to be generated forever. -Smooth the input video. +@item test, t -The filter takes the following parameters: -@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}. +Set the number or the name of the test to perform. Supported tests are: +@table @option +@item dc_luma +@item dc_chroma +@item freq_luma +@item freq_chroma +@item amp_luma +@item amp_chroma +@item cbp +@item mv +@item ring1 +@item ring2 +@item all +@end table -@var{type} is the type of smooth filter to apply, and can be one of -the following values: "blur", "blur_no_scale", "median", "gaussian", -"bilateral". The default value is "gaussian". +Default value is "all", which will cycle through the list of all tests. +@end table -@var{param1}, @var{param2}, @var{param3}, and @var{param4} are -parameters whose meanings depend on smooth type. @var{param1} and -@var{param2} accept integer positive values or 0, @var{param3} and -@var{param4} accept float values. +For example the following: +@example +testsrc=t=dc_luma +@end example -The default value for @var{param1} is 3, the default value for the -other parameters is 0. +will generate a "dc_luma" test pattern. -These parameters correspond to the parameters assigned to the -libopencv function @code{cvSmooth}. +@section frei0r_src -@anchor{overlay} -@section overlay +Provide a frei0r source. -Overlay one video on top of another. +To enable compilation of this filter you need to install the frei0r +header and configure FFmpeg with @code{--enable-frei0r}. -It takes two inputs and one output, the first input is the "main" -video on which the second input is overlayed. +This source accepts the following options: -It accepts the parameters: @var{x}:@var{y}. +@table @option -@var{x} is the x coordinate of the overlayed video on the main video, -@var{y} is the y coordinate. The parameters are expressions containing -the following parameters: +@item size +The size of the video to generate, may be a string of the form +@var{width}x@var{height} or a frame size abbreviation. -@table @option -@item main_w, main_h -main input width and height +@item framerate +Framerate of the generated video, may be a string of the form +@var{num}/@var{den} or a frame rate abbreviation. -@item W, H -same as @var{main_w} and @var{main_h} +@item filter_name +The name to the frei0r source to load. For more information regarding frei0r and +how to set the parameters read the section @ref{frei0r} in the description of +the video filters. -@item overlay_w, overlay_h -overlay input width and height +@item filter_params +A '|'-separated list of parameters to pass to the frei0r source. -@item w, h -same as @var{overlay_w} and @var{overlay_h} @end table -Be aware that frames are taken from each input video in timestamp -order, hence, if their initial timestamps differ, it is a a good idea -to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to -have them begin in the same zero timestamp, as it does the example for -the @var{movie} filter. - -Follow some examples: +For example, to generate a frei0r partik0l source with size 200x200 +and frame rate 10 which is overlayed on the overlay filter main input: @example -# draw the overlay at 10 pixels from the bottom right -# corner of the main video. -overlay=main_w-overlay_w-10:main_h-overlay_h-10 +frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay +@end example -# insert a transparent PNG logo in the bottom left corner of the input -avconv -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output +@section life -# insert 2 different transparent PNG logos (second logo on bottom -# right corner): -avconv -i input -i logo1 -i logo2 -filter_complex -'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output +Generate a life pattern. -# add a transparent color layer on top of the main video, -# WxH specifies the size of the main input to the overlay filter -color=red@.3:WxH [over]; [in][over] overlay [out] -@end example +This source is based on a generalization of John Conway's life game. -You can chain together more overlays but the efficiency of such -approach is yet to be tested. +The sourced input represents a life grid, each pixel represents a cell +which can be in one of two possible states, alive or dead. Every cell +interacts with its eight neighbours, which are the cells that are +horizontally, vertically, or diagonally adjacent. -@section pad +At each interaction the grid evolves according to the adopted rule, +which specifies the number of neighbor alive cells which will make a +cell stay alive or born. The @option{rule} option allows to specify +the rule to adopt. -Add paddings to the input image, and places the original input at the -given coordinates @var{x}, @var{y}. +This source accepts a list of options in the form of +@var{key}=@var{value} pairs separated by ":". A description of the +accepted options follows. -It accepts the following parameters: -@var{width}:@var{height}:@var{x}:@var{y}:@var{color}. +@table @option +@item filename, f +Set the file from which to read the initial grid state. In the file, +each non-whitespace character is considered an alive cell, and newline +is used to delimit the end of each row. -The parameters @var{width}, @var{height}, @var{x}, and @var{y} are -expressions containing the following constants: +If this option is not specified, the initial grid is generated +randomly. -@table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), phi (golden ratio) +@item rate, r +Set the video rate, that is the number of frames generated per second. +Default is 25. + +@item random_fill_ratio, ratio +Set the random fill ratio for the initial random grid. It is a +floating point number value ranging from 0 to 1, defaults to 1/PHI. +It is ignored when a file is specified. + +@item random_seed, seed +Set the seed for filling the initial random grid, must be an integer +included between 0 and UINT32_MAX. If not specified, or if explicitly +set to -1, the filter will try to use a good random seed on a best +effort basis. + +@item rule +Set the life rule. + +A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}", +where @var{NS} and @var{NB} are sequences of numbers in the range 0-8, +@var{NS} specifies the number of alive neighbor cells which make a +live cell stay alive, and @var{NB} the number of alive neighbor cells +which make a dead cell to become alive (i.e. to "born"). +"s" and "b" can be used in place of "S" and "B", respectively. + +Alternatively a rule can be specified by an 18-bits integer. The 9 +high order bits are used to encode the next cell state if it is alive +for each number of neighbor alive cells, the low order bits specify +the rule for "borning" new cells. Higher order bits encode for an +higher number of neighbor cells. +For example the number 6153 = @code{(12<<9)+9} specifies a stay alive +rule of 12 and a born rule of 9, which corresponds to "S23/B03". + +Default value is "S23/B3", which is the original Conway's game of life +rule, and will keep a cell alive if it has 2 or 3 neighbor alive +cells, and will born a new cell if there are three alive cells around +a dead cell. -@item in_w, in_h -the input video width and height +@item size, s +Set the size of the output video. -@item iw, ih -same as @var{in_w} and @var{in_h} +If @option{filename} is specified, the size is set by default to the +same size of the input file. If @option{size} is set, it must contain +the size specified in the input file, and the initial grid defined in +that file is centered in the larger resulting area. -@item out_w, out_h -the output width and height, that is the size of the padded area as -specified by the @var{width} and @var{height} expressions +If a filename is not specified, the size value defaults to "320x240" +(used for a randomly generated initial grid). -@item ow, oh -same as @var{out_w} and @var{out_h} +@item stitch +If set to 1, stitch the left and right grid edges together, and the +top and bottom edges also. Defaults to 1. -@item x, y -x and y offsets as specified by the @var{x} and @var{y} -expressions, or NAN if not yet specified +@item mold +Set cell mold speed. If set, a dead cell will go from @option{death_color} to +@option{mold_color} with a step of @option{mold}. @option{mold} can have a +value from 0 to 255. -@item a -input display aspect ratio, same as @var{iw} / @var{ih} +@item life_color +Set the color of living (or new born) cells. -@item hsub, vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@item death_color +Set the color of dead cells. If @option{mold} is set, this is the first color +used to represent a dead cell. + +@item mold_color +Set mold color, for definitely dead and moldy cells. @end table -Follows the description of the accepted parameters. +@subsection Examples -@table @option -@item width, height +@itemize +@item +Read a grid from @file{pattern}, and center it on a grid of size +300x300 pixels: +@example +life=f=pattern:s=300x300 +@end example -Specify the size of the output image with the paddings added. If the -value for @var{width} or @var{height} is 0, the corresponding input size -is used for the output. +@item +Generate a random grid of size 200x200, with a fill ratio of 2/3: +@example +life=ratio=2/3:s=200x200 +@end example -The @var{width} expression can reference the value set by the -@var{height} expression, and vice versa. +@item +Specify a custom rule for evolving a randomly generated grid: +@example +life=rule=S14/B34 +@end example -The default value of @var{width} and @var{height} is 0. +@item +Full example with slow death effect (mold) using @command{ffplay}: +@example +ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16 +@end example +@end itemize -@item x, y +@section color, nullsrc, rgbtestsrc, smptebars, testsrc -Specify the offsets where to place the input image in the padded area -with respect to the top/left border of the output image. +The @code{color} source provides an uniformly colored input. -The @var{x} expression can reference the value set by the @var{y} -expression, and vice versa. +The @code{nullsrc} source returns unprocessed video frames. It is +mainly useful to be employed in analysis / debugging tools, or as the +source for filters which ignore the input data. -The default value of @var{x} and @var{y} is 0. +The @code{rgbtestsrc} source generates an RGB test pattern useful for +detecting RGB vs BGR issues. You should see a red, green and blue +stripe from top to bottom. -@item color +The @code{smptebars} source generates a color bars pattern, based on +the SMPTE Engineering Guideline EG 1-1990. -Specify the color of the padded area, it can be the name of a color -(case insensitive match) or a 0xRRGGBB[AA] sequence. +The @code{testsrc} source generates a test video pattern, showing a +color pattern, a scrolling gradient and a timestamp. This is mainly +intended for testing purposes. -The default value of @var{color} is "black". +These sources accept an optional sequence of @var{key}=@var{value} pairs, +separated by ":". The description of the accepted options follows. -@end table +@table @option + +@item color, c +Specify the color of the source, only used in the @code{color} +source. It can be the name of a color (case insensitive match) or a +0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The +default value is "black". + +@item size, s +Specify the size of the sourced video, it may be a string of the form +@var{width}x@var{height}, or the name of a size abbreviation. The +default value is "320x240". -Some examples follow: +@item rate, r +Specify the frame rate of the sourced video, as the number of frames +generated per second. It has to be a string in the format +@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float +number or a valid video frame rate abbreviation. The default value is +"25". + +@item sar +Set the sample aspect ratio of the sourced video. +@item duration, d +Set the video duration of the sourced video. The accepted syntax is: @example -# Add paddings with color "violet" to the input video. Output video -# size is 640x480, the top-left corner of the input video is placed at -# column 0, row 40. -pad=640:480:0:40:violet +[-]HH[:MM[:SS[.m...]]] +[-]S+[.m...] +@end example +See also the function @code{av_parse_time()}. -# pad the input to get an output with dimensions increased bt 3/2, -# and put the input video at the center of the padded area -pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2" +If not specified, or the expressed duration is negative, the video is +supposed to be generated forever. -# pad the input to get a squared output with size equal to the maximum -# value between the input width and height, and put the input video at -# the center of the padded area -pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2" +@item decimals, n +Set the number of decimals to show in the timestamp, only used in the +@code{testsrc} source. -# pad the input to get a final w/h ratio of 16:9 -pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2" +The displayed timestamp value will correspond to the original +timestamp value multiplied by the power of 10 of the specified +value. Default value is 0. +@end table -# double output size and put the input video in the bottom-right -# corner of the output padded area -pad="2*iw:2*ih:ow-iw:oh-ih" +For example the following: +@example +testsrc=duration=5.3:size=qcif:rate=10 @end example -@section pixdesctest +will generate a video with a duration of 5.3 seconds, with size +176x144 and a frame rate of 10 frames per second. -Pixel format descriptor test filter, mainly useful for internal -testing. The output video should be equal to the input video. +The following graph description will generate a red source +with an opacity of 0.2, with size "qcif" and a frame rate of 10 +frames per second. +@example +color=c=red@@0.2:s=qcif:r=10 +@end example -For example: +If the input content is to be ignored, @code{nullsrc} can be used. The +following command generates noise in the luminance plane by employing +the @code{geq} filter: @example -format=monow, pixdesctest +nullsrc=s=256x256, geq=random(1)*255:128:128 @end example -can be used to test the monowhite pixel format descriptor definition. +@c man end VIDEO SOURCES -@section scale +@chapter Video Sinks +@c man begin VIDEO SINKS + +Below is a description of the currently available video sinks. -Scale the input video and/or convert the image format. +@section buffersink -This filter accepts the following options: +Buffer video frames, and make them available to the end of the filter +graph. -@table @option +This sink is mainly intended for a programmatic use, in particular +through the interface defined in @file{libavfilter/buffersink.h}. -@item w -Output video width. +It does not require a string parameter in input, but you need to +specify a pointer to a list of supported pixel formats terminated by +-1 in the opaque parameter provided to @code{avfilter_init_filter} +when initializing this sink. -@item h -Output video height. +@section nullsink + +Null video sink, do absolutely nothing with the input video. It is +mainly useful as a template and to be employed in analysis / debugging +tools. + +@c man end VIDEO SINKS -@end table +@chapter Multimedia Filters +@c man begin MULTIMEDIA FILTERS -The parameters @var{w} and @var{h} are expressions containing -the following constants: +Below is a description of the currently available multimedia filters. -@table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), phi (golden ratio) +@section aperms, perms -@item in_w, in_h -the input width and height +Set read/write permissions for the output frames. -@item iw, ih -same as @var{in_w} and @var{in_h} +These filters are mainly aimed at developers to test direct path in the +following filter in the filtergraph. -@item out_w, out_h -the output (cropped) width and height +The filters accept parameters as a list of @var{key}=@var{value} pairs, +separated by ":". If the key of the first options is omitted, the argument is +assumed to be the @var{mode}. -@item ow, oh -same as @var{out_w} and @var{out_h} +A description of the accepted parameters follows. -@item dar, a -input display aspect ratio, same as @var{iw} / @var{ih} +@table @option +@item mode +Select the permissions mode. -@item sar -input sample aspect ratio +It accepts the following values: +@table @samp +@item none +Do nothing. This is the default. +@item ro +Set all the output frames read-only. +@item rw +Set all the output frames directly writable. +@item toggle +Make the frame read-only if writable, and writable if read-only. +@item random +Set each output frame read-only or writable randomly. +@end table -@item hsub, vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. +@item seed +Set the seed for the @var{random} mode, must be an integer included between +@code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to +@code{-1}, the filter will try to use a good random seed on a best effort +basis. @end table -If the input image format is different from the format requested by -the next filter, the scale filter will convert the input to the -requested format. +Note: in case of auto-inserted filter between the permission filter and the +following one, the permission might not be received as expected in that +following filter. Inserting a @ref{format} or @ref{aformat} filter before the +perms/aperms filter can avoid this problem. -If the value for @var{w} or @var{h} is 0, the respective input -size is used for the output. +@section aphaser +Add a phasing effect to the input audio. -If the value for @var{w} or @var{h} is -1, the scale filter will use, for the -respective output size, a value that maintains the aspect ratio of the input -image. +A phaser filter creates series of peaks and troughs in the frequency spectrum. +The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect. -The default value of @var{w} and @var{h} is 0. +The filter accepts parameters as a list of @var{key}=@var{value} +pairs, separated by ":". -Some examples follow: -@example -# scale the input video to a size of 200x100. -scale=w=200:h=100 +A description of the accepted parameters follows. -# scale the input to 2x -scale=w=2*iw:h=2*ih -# the above is the same as -scale=2*in_w:2*in_h +@table @option +@item in_gain +Set input gain. Default is 0.4. -# scale the input to half size -scale=w=iw/2:h=ih/2 +@item out_gain +Set output gain. Default is 0.74 -# increase the width, and set the height to the same size -scale=3/2*iw:ow +@item delay +Set delay in milliseconds. Default is 3.0. -# seek for Greek harmony -scale=iw:1/PHI*iw -scale=ih*PHI:ih +@item decay +Set decay. Default is 0.4. -# increase the height, and set the width to 3/2 of the height -scale=w=3/2*oh:h=3/5*ih +@item speed +Set modulation speed in Hz. Default is 0.5. -# increase the size, but make the size a multiple of the chroma -scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub" +@item type +Set modulation type. Default is triangular. -# increase the width to a maximum of 500 pixels, keep the same input aspect ratio -scale=w='min(500\, iw*3/2):h=-1' -@end example +It accepts the following values: +@table @samp +@item triangular, t +@item sinusoidal, s +@end table +@end table -@section select +@section aselect, select Select frames to pass in output. -It accepts in input an expression, which is evaluated for each input -frame. If the expression is evaluated to a non-zero value, the frame -is selected and passed to the output, otherwise it is discarded. +These filters accept a single option @option{expr} or @option{e} +specifying the select expression, which can be specified either by +specyfing @code{expr=VALUE} or specifying the expression +alone. + +The select expression is evaluated for each input frame. If the +evaluation result is a non-zero value, the frame is selected and +passed to the output, otherwise it is discarded. The expression can contain the following constants: @table @option -@item PI -Greek PI - -@item PHI -golden ratio - -@item E -Euler number - @item n the sequential number of the filtered frame, starting from 0 @@ -1796,7 +6486,7 @@ the PTS of the first video frame in the video, NAN if undefined @item start_t the time of the first video frame in the video, NAN if undefined -@item pict_type +@item pict_type @emph{(video only)} the type of the filtered frame, can assume one of the following values: @table @option @@ -1809,7 +6499,7 @@ values: @item BI @end table -@item interlace_type +@item interlace_type @emph{(video only)} the frame interlace type, can assume one of the following values: @table @option @item PROGRESSIVE @@ -1820,509 +6510,695 @@ the frame is top-field-first the frame is bottom-field-first @end table +@item consumed_sample_n @emph{(audio only)} +the number of selected samples before the current frame + +@item samples_n @emph{(audio only)} +the number of samples in the current frame + +@item sample_rate @emph{(audio only)} +the input sample rate + @item key 1 if the filtered frame is a key-frame, 0 otherwise +@item pos +the position in the file of the filtered frame, -1 if the information +is not available (e.g. for synthetic video) + +@item scene @emph{(video only)} +value between 0 and 1 to indicate a new scene; a low value reflects a low +probability for the current frame to introduce a new scene, while a higher +value means the current frame is more likely to be one (see the example below) + @end table The default value of the select expression is "1". -Some examples follow: +@subsection Examples +@itemize +@item +Select all frames in input: @example -# select all frames in input select +@end example -# the above is the same as: +The example above is the same as: +@example select=1 +@end example -# skip all frames: +@item +Skip all frames: +@example select=0 +@end example -# select only I-frames +@item +Select only I-frames: +@example select='eq(pict_type\,I)' +@end example -# select one frame every 100 +@item +Select one frame every 100: +@example select='not(mod(n\,100))' +@end example -# select only frames contained in the 10-20 time interval +@item +Select only frames contained in the 10-20 time interval: +@example select='gte(t\,10)*lte(t\,20)' +@end example -# select only I frames contained in the 10-20 time interval +@item +Select only I frames contained in the 10-20 time interval: +@example select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)' +@end example -# select frames with a minimum distance of 10 seconds +@item +Select frames with a minimum distance of 10 seconds: +@example select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)' @end example -@anchor{setdar} -@section setdar +@item +Use aselect to select only audio frames with samples number > 100: +@example +aselect='gt(samples_n\,100)' +@end example + +@item +Create a mosaic of the first scenes: +@example +ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png +@end example -Set the Display Aspect Ratio for the filter output video. +Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane +choice. +@end itemize -This is done by changing the specified Sample (aka Pixel) Aspect -Ratio, according to the following equation: -@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} +@section asendcmd, sendcmd -Keep in mind that this filter does not modify the pixel dimensions of -the video frame. Also the display aspect ratio set by this filter may -be changed by later filters in the filterchain, e.g. in case of -scaling or if another "setdar" or a "setsar" filter is applied. +Send commands to filters in the filtergraph. -This filter accepts the following options: +These filters read commands to be sent to other filters in the +filtergraph. +@code{asendcmd} must be inserted between two audio filters, +@code{sendcmd} must be inserted between two video filters, but apart +from that they act the same way. + +The specification of commands can be provided in the filter arguments +with the @var{commands} option, or in a file specified by the +@var{filename} option. + +These filters accept the following options: @table @option +@item commands, c +Set the commands to be read and sent to the other filters. +@item filename, f +Set the filename of the commands to be read and sent to the other +filters. +@end table -@item dar -Output display aspect ratio, as a rational or a decimal number. +@subsection Commands syntax + +A commands description consists of a sequence of interval +specifications, comprising a list of commands to be executed when a +particular event related to that interval occurs. The occurring event +is typically the current frame time entering or leaving a given time +interval. + +An interval is specified by the following syntax: +@example +@var{START}[-@var{END}] @var{COMMANDS}; +@end example +The time interval is specified by the @var{START} and @var{END} times. +@var{END} is optional and defaults to the maximum time. + +The current frame time is considered within the specified interval if +it is included in the interval [@var{START}, @var{END}), that is when +the time is greater or equal to @var{START} and is lesser than +@var{END}. + +@var{COMMANDS} consists of a sequence of one or more command +specifications, separated by ",", relating to that interval. The +syntax of a command specification is given by: +@example +[@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG} +@end example + +@var{FLAGS} is optional and specifies the type of events relating to +the time interval which enable sending the specified command, and must +be a non-null sequence of identifier flags separated by "+" or "|" and +enclosed between "[" and "]". + +The following flags are recognized: +@table @option +@item enter +The command is sent when the current frame timestamp enters the +specified interval. In other words, the command is sent when the +previous frame timestamp was not in the given interval, and the +current is. + +@item leave +The command is sent when the current frame timestamp leaves the +specified interval. In other words, the command is sent when the +previous frame timestamp was in the given interval, and the +current is not. @end table -For example to change the display aspect ratio to 16:9, specify: +If @var{FLAGS} is not specified, a default value of @code{[enter]} is +assumed. + +@var{TARGET} specifies the target of the command, usually the name of +the filter class or a specific filter instance name. + +@var{COMMAND} specifies the name of the command for the target filter. + +@var{ARG} is optional and specifies the optional list of argument for +the given @var{COMMAND}. + +Between one interval specification and another, whitespaces, or +sequences of characters starting with @code{#} until the end of line, +are ignored and can be used to annotate comments. + +A simplified BNF description of the commands specification syntax +follows: @example -setdar=dar=16/9 -# the above is equivalent to -setdar=dar=1.77777 +@var{COMMAND_FLAG} ::= "enter" | "leave" +@var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}] +@var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}] +@var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}] +@var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS} +@var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}] @end example -See also the @ref{setsar} filter documentation. +@subsection Examples + +@itemize +@item +Specify audio tempo change at second 4: +@example +asendcmd=c='4.0 atempo tempo 1.5',atempo +@end example + +@item +Specify a list of drawtext and hue commands in a file. +@example +# show text in the interval 5-10 +5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world', + [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text='; + +# desaturate the image in the interval 15-20 +15.0-20.0 [enter] hue reinit s=0, + [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor', + [leave] hue reinit s=1, + [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color'; + +# apply an exponential saturation fade-out effect, starting from time 25 +25 [enter] hue s=exp(t-25) +@end example + +A filtergraph allowing to read and process the above command list +stored in a file @file{test.cmd}, can be specified with: +@example +sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue +@end example +@end itemize -@section setpts +@anchor{setpts} +@section asetpts, setpts -Change the PTS (presentation timestamp) of the input video frames. +Change the PTS (presentation timestamp) of the input frames. + +@code{asetpts} works on audio frames, @code{setpts} on video frames. Accept in input an expression evaluated through the eval API, which can contain the following constants: @table @option +@item FRAME_RATE +frame rate, only defined for constant frame-rate video + @item PTS the presentation timestamp in input -@item PI -Greek PI +@item N +the count of the input frame, starting from 0. -@item PHI -golden ratio +@item NB_CONSUMED_SAMPLES +the number of consumed samples, not including the current frame (only +audio) -@item E -Euler number +@item NB_SAMPLES +the number of samples in the current frame (only audio) -@item N -the count of the input frame, starting from 0. +@item SAMPLE_RATE +audio sample rate @item STARTPTS -the PTS of the first video frame +the PTS of the first frame + +@item STARTT +the time in seconds of the first frame @item INTERLACED tell if the current frame is interlaced +@item T +the time in seconds of the current frame + +@item TB +the time base + +@item POS +original position in the file of the frame, or undefined if undefined +for the current frame + @item PREV_INPTS previous input PTS +@item PREV_INT +previous input time in seconds + @item PREV_OUTPTS previous output PTS +@item PREV_OUTT +previous output time in seconds + @item RTCTIME -wallclock (RTC) time in microseconds +wallclock (RTC) time in microseconds. This is deprecated, use time(0) +instead. @item RTCSTART wallclock (RTC) time at the start of the movie in microseconds - @end table -Some examples follow: +@subsection Examples +@itemize +@item +Start counting PTS from zero @example -# start counting PTS from zero setpts=PTS-STARTPTS +@end example -# fast motion +@item +Apply fast motion effect: +@example setpts=0.5*PTS +@end example -# slow motion +@item +Apply slow motion effect: +@example setpts=2.0*PTS +@end example -# fixed rate 25 fps +@item +Set fixed rate of 25 frames per second: +@example setpts=N/(25*TB) +@end example -# fixed rate 25 fps with some jitter +@item +Set fixed rate 25 fps with some jitter: +@example setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' - -# generate timestamps from a "live source" and rebase onto the current timebase -setpts='(RTCTIME - RTCSTART) / (TB * 1000000)" @end example -@anchor{setsar} -@section setsar - -Set the Sample (aka Pixel) Aspect Ratio for the filter output video. - -Note that as a consequence of the application of this filter, the -output display aspect ratio will change according to the following -equation: -@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR} - -Keep in mind that the sample aspect ratio set by this filter may be -changed by later filters in the filterchain, e.g. if another "setsar" -or a "setdar" filter is applied. - -This filter accepts the following options: - -@table @option - -@item sar -Output sample aspect ratio, as a rational or decimal number. - -@end table - -For example to change the sample aspect ratio to 10:11, specify: +@item +Apply an offset of 10 seconds to the input PTS: @example -setsar=sar=10/11 +setpts=PTS+10/TB @end example -@section settb - -Set the timebase to use for the output frames timestamps. -It is mainly useful for testing timebase configuration. - -It accepts in input an arithmetic expression representing a rational. -The expression can contain the constants "PI", "E", "PHI", "AVTB" (the -default timebase), and "intb" (the input timebase). - -The default value for the input is "intb". - -Follow some examples. - +@item +Generate timestamps from a "live source" and rebase onto the current timebase: @example -# set the timebase to 1/25 -settb=1/25 - -# set the timebase to 1/10 -settb=0.1 - -#set the timebase to 1001/1000 -settb=1+0.001 - -#set the timebase to 2*intb -settb=2*intb - -#set the default timebase value -settb=AVTB +setpts='(RTCTIME - RTCSTART) / (TB * 1000000)' @end example +@end itemize -@section showinfo - -Show a line containing various information for each input video frame. -The input video is not modified. - -The shown line contains a sequence of key/value pairs of the form -@var{key}:@var{value}. - -A description of each shown parameter follows: +@section ebur128 -@table @option -@item n -sequential number of the input frame, starting from 0 +EBU R128 scanner filter. This filter takes an audio stream as input and outputs +it unchanged. By default, it logs a message at a frequency of 10Hz with the +Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}), +Integrated loudness (@code{I}) and Loudness Range (@code{LRA}). -@item pts -Presentation TimeStamp of the input frame, expressed as a number of -time base units. The time base unit depends on the filter input pad. +The filter also has a video output (see the @var{video} option) with a real +time graph to observe the loudness evolution. The graphic contains the logged +message mentioned above, so it is not printed anymore when this option is set, +unless the verbose logging is set. The main graphing area contains the +short-term loudness (3 seconds of analysis), and the gauge on the right is for +the momentary loudness (400 milliseconds). -@item pts_time -Presentation TimeStamp of the input frame, expressed as a number of -seconds +More information about the Loudness Recommendation EBU R128 on +@url{http://tech.ebu.ch/loudness}. -@item pos -position of the frame in the input stream, -1 if this information in -unavailable and/or meaningless (for example in case of synthetic video) +The filter accepts the following named parameters: -@item fmt -pixel format name +@table @option -@item sar -sample aspect ratio of the input frame, expressed in the form -@var{num}/@var{den} +@item video +Activate the video output. The audio stream is passed unchanged whether this +option is set or no. The video stream will be the first output stream if +activated. Default is @code{0}. -@item s -size of the input frame, expressed in the form -@var{width}x@var{height} +@item size +Set the video size. This option is for video only. Default and minimum +resolution is @code{640x480}. -@item i -interlaced mode ("P" for "progressive", "T" for top field first, "B" -for bottom field first) +@item meter +Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and +@code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any +other integer value between this range is allowed. -@item iskey -1 if the frame is a key frame, 0 otherwise +@item metadata +Set metadata injection. If set to @code{1}, the audio input will be segmented +into 100ms output frames, each of them containing various loudness information +in metadata. All the metadata keys are prefixed with @code{lavfi.r128.}. -@item type -picture type of the input frame ("I" for an I-frame, "P" for a -P-frame, "B" for a B-frame, "?" for unknown type). -Check also the documentation of the @code{AVPictureType} enum and of -the @code{av_get_picture_type_char} function defined in -@file{libavutil/avutil.h}. +Default is @code{0}. -@item checksum -Adler-32 checksum of all the planes of the input frame +@item framelog +Force the frame logging level. -@item plane_checksum -Adler-32 checksum of each plane of the input frame, expressed in the form -"[@var{c0} @var{c1} @var{c2} @var{c3}]" +Available values are: +@table @samp +@item info +information logging level +@item verbose +verbose logging level @end table -@section split +By default, the logging level is set to @var{info}. If the @option{video} or +the @option{metadata} options are set, it switches to @var{verbose}. +@end table -Split input video into several identical outputs. +@subsection Examples -The filter accepts a single parameter which specifies the number of outputs. If -unspecified, it defaults to 2. +@itemize +@item +Real-time graph using @command{ffplay}, with a EBU scale meter +18: +@example +ffplay -f lavfi -i "amovie=input.mp3,ebur128=video=1:meter=18 [out0][out1]" +@end example -For example +@item +Run an analysis with @command{ffmpeg}: @example -avconv -i INPUT -filter_complex split=5 OUTPUT +ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null - @end example -will create 5 copies of the input video. +@end itemize -@section transpose +@section settb, asettb -Transpose rows with columns in the input video and optionally flip it. +Set the timebase to use for the output frames timestamps. +It is mainly useful for testing timebase configuration. -It accepts a parameter representing an integer, which can assume the -values: +This filter accepts a single option @option{tb}, which can be +specified either by setting @option{tb}=@var{VALUE} or setting the +value alone. + +The value for @option{tb} is an arithmetic expression representing a +rational. The expression can contain the constants "AVTB" (the default +timebase), "intb" (the input timebase) and "sr" (the sample rate, +audio only). Default value is "intb". + +@subsection Examples -@table @samp -@item 0 -Rotate by 90 degrees counterclockwise and vertically flip (default), that is: +@itemize +@item +Set the timebase to 1/25: @example -L.R L.l -. . -> . . -l.r R.r +settb=1/25 @end example -@item 1 -Rotate by 90 degrees clockwise, that is: +@item +Set the timebase to 1/10: @example -L.R l.L -. . -> . . -l.r r.R +settb=0.1 @end example -@item 2 -Rotate by 90 degrees counterclockwise, that is: +@item +Set the timebase to 1001/1000: @example -L.R R.r -. . -> . . -l.r L.l +settb=1+0.001 @end example -@item 3 -Rotate by 90 degrees clockwise and vertically flip, that is: +@item +Set the timebase to 2*intb: @example -L.R r.R -. . -> . . -l.r l.L +settb=2*intb @end example -@end table -@section unsharp +@item +Set the default timebase value: +@example +settb=AVTB +@end example +@end itemize -Sharpen or blur the input video. +@section concat -It accepts the following parameters: -@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount} +Concatenate audio and video streams, joining them together one after the +other. -Negative values for the amount will blur the input video, while positive -values will sharpen. All parameters are optional and default to the -equivalent of the string '5:5:1.0:5:5:0.0'. +The filter works on segments of synchronized video and audio streams. All +segments must have the same number of streams of each type, and that will +also be the number of streams at output. +The filter accepts the following named parameters: @table @option -@item luma_msize_x -Set the luma matrix horizontal size. It can be an integer between 3 -and 13, default value is 5. +@item n +Set the number of segments. Default is 2. -@item luma_msize_y -Set the luma matrix vertical size. It can be an integer between 3 -and 13, default value is 5. +@item v +Set the number of output video streams, that is also the number of video +streams in each segment. Default is 1. -@item luma_amount -Set the luma effect strength. It can be a float number between -2.0 -and 5.0, default value is 1.0. +@item a +Set the number of output audio streams, that is also the number of video +streams in each segment. Default is 0. -@item chroma_msize_x -Set the chroma matrix horizontal size. It can be an integer between 3 -and 13, default value is 5. +@item unsafe +Activate unsafe mode: do not fail if segments have a different format. -@item chroma_msize_y -Set the chroma matrix vertical size. It can be an integer between 3 -and 13, default value is 5. +@end table -@item luma_amount -Set the chroma effect strength. It can be a float number between -2.0 -and 5.0, default value is 0.0. +The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then +@var{a} audio outputs. -@end table +There are @var{n}x(@var{v}+@var{a}) inputs: first the inputs for the first +segment, in the same order as the outputs, then the inputs for the second +segment, etc. -@example -# Strong luma sharpen effect parameters -unsharp=7:7:2.5 +Related streams do not always have exactly the same duration, for various +reasons including codec frame size or sloppy authoring. For that reason, +related synchronized streams (e.g. a video and its audio track) should be +concatenated at once. The concat filter will use the duration of the longest +stream in each segment (except the last one), and if necessary pad shorter +audio streams with silence. -# Strong blur of both luma and chroma parameters -unsharp=7:7:-2:7:7:-2 +For this filter to work correctly, all segments must start at timestamp 0. -# Use the default values with @command{avconv} -./avconv -i in.avi -vf "unsharp" out.mp4 -@end example +All corresponding streams must have the same parameters in all segments; the +filtering system will automatically select a common pixel format for video +streams, and a common sample format, sample rate and channel layout for +audio streams, but other settings, such as resolution, must be converted +explicitly by the user. -@section vflip +Different frame rates are acceptable but will result in variable frame rate +at output; be sure to configure the output file to handle it. -Flip the input video vertically. +@subsection Examples +@itemize +@item +Concatenate an opening, an episode and an ending, all in bilingual version +(video in stream 0, audio in streams 1 and 2): @example -./avconv -i in.avi -vf "vflip" out.avi +ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \ + '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2] + concat=n=3:v=1:a=2 [v] [a1] [a2]' \ + -map '[v]' -map '[a1]' -map '[a2]' output.mkv @end example -@section yadif +@item +Concatenate two parts, handling audio and video separately, using the +(a)movie sources, and adjusting the resolution: +@example +movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ; +movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ; +[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa] +@end example +Note that a desync will happen at the stitch if the audio and video streams +do not have exactly the same duration in the first file. -Deinterlace the input video ("yadif" means "yet another deinterlacing -filter"). +@end itemize -It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}. +@section showspectrum -@var{mode} specifies the interlacing mode to adopt, accepts one of the -following values: +Convert input audio to a video output, representing the audio frequency +spectrum. +The filter accepts the following named parameters: @table @option -@item 0 -output 1 frame for each frame -@item 1 -output 1 frame for each field -@item 2 -like 0 but skips spatial interlacing check -@item 3 -like 1 but skips spatial interlacing check -@end table +@item size, s +Specify the video size for the output. Default value is @code{640x512}. -Default value is 0. +@item slide +Specify if the spectrum should slide along the window. Default value is +@code{0}. -@var{parity} specifies the picture field parity assumed for the input -interlaced video, accepts one of the following values: +@item mode +Specify display mode. -@table @option -@item 0 -assume top field first -@item 1 -assume bottom field first -@item -1 -enable automatic detection +It accepts the following values: +@table @samp +@item combined +all channels are displayed in the same row +@item separate +all channels are displayed in separate rows @end table -Default value is -1. -If interlacing is unknown or decoder does not export this information, -top field first will be assumed. +Default value is @samp{combined}. -@var{auto} specifies if deinterlacer should trust the interlaced flag -and only deinterlace frames marked as interlaced +@item color +Specify display color mode. -@table @option -@item 0 -deinterlace all frames -@item 1 -only deinterlace frames marked as interlaced +It accepts the following values: +@table @samp +@item channel +each channel is displayed in a separate color +@item intensity +each channel is is displayed using the same color scheme @end table -Default value is 0. - -@c man end VIDEO FILTERS +Default value is @samp{channel}. -@chapter Video Sources -@c man begin VIDEO SOURCES +@item scale +Specify scale used for calculating intensity color values. -Below is a description of the currently available video sources. +It accepts the following values: +@table @samp +@item lin +linear +@item sqrt +square root, default +@item cbrt +cubic root +@item log +logarithmic +@end table -@section buffer +Default value is @samp{sqrt}. -Buffer video frames, and make them available to the filter chain. +@item saturation +Set saturation modifier for displayed colors. Negative values provide +alternative color scheme. @code{0} is no saturation at all. +Saturation must be in [-10.0, 10.0] range. +Default value is @code{1}. +@end table -This source is mainly intended for a programmatic use, in particular -through the interface defined in @file{libavfilter/vsrc_buffer.h}. +The usage is very similar to the showwaves filter; see the examples in that +section. -This filter accepts the following parameters: +@subsection Examples -@table @option +@itemize +@item +Large window with logarithmic color scaling: +@example +showspectrum=s=1280x480:scale=log +@end example -@item width -Input video width. +@item +Complete example for a colored and sliding spectrum per channel using @command{ffplay}: +@example +ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1]; + [a] showspectrum=mode=separate:color=intensity:slide=1:scale=cbrt [out0]' +@end example +@end itemize -@item height -Input video height. +@section showwaves -@item pix_fmt -Name of the input video pixel format. +Convert input audio to a video output, representing the samples waves. -@item time_base -The time base used for input timestamps. +The filter accepts the following named parameters: +@table @option +@item mode +Set display mode. -@item sar -Sample (pixel) aspect ratio of the input video. +Available values are: +@table @samp +@item point +Draw a point for each sample. +@item line +Draw a vertical line for each sample. @end table -For example: -@example -buffer=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1 -@end example - -will instruct the source to accept video frames with size 320x240 and -with format "yuv410p", assuming 1/24 as the timestamps timebase and -square pixels (1:1 sample aspect ratio). +Default value is @code{point}. -@section color +@item n +Set the number of samples which are printed on the same column. A +larger value will decrease the frame rate. Must be a positive +integer. This option can be set only if the value for @var{rate} +is not explicitly specified. -Provide an uniformly colored input. +@item rate, r +Set the (approximate) output frame rate. This is done by setting the +option @var{n}. Default value is "25". -It accepts the following parameters: -@var{color}:@var{frame_size}:@var{frame_rate} +@item size, s +Specify the video size for the output. Default value is "600x240". +@end table -Follows the description of the accepted parameters. +@subsection Examples -@table @option +@itemize +@item +Output the input file audio and the corresponding video representation +at the same time: +@example +amovie=a.mp3,asplit[out0],showwaves[out1] +@end example -@item color -Specify the color of the source. It can be the name of a color (case -insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an -alpha specifier. The default value is "black". +@item +Create a synthetic signal and show it with showwaves, forcing a +frame rate of 30 frames per second: +@example +aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1] +@end example +@end itemize -@item frame_size -Specify the size of the sourced video, it may be a string of the form -@var{width}x@var{height}, or the name of a size abbreviation. The -default value is "320x240". +@c man end MULTIMEDIA FILTERS -@item frame_rate -Specify the frame rate of the sourced video, as the number of frames -generated per second. It has to be a string in the format -@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float -number or a valid video frame rate abbreviation. The default value is -"25". +@chapter Multimedia Sources +@c man begin MULTIMEDIA SOURCES -@end table +Below is a description of the currently available multimedia sources. -For example the following graph description will generate a red source -with an opacity of 0.2, with size "qcif" and a frame rate of 10 -frames per second, which will be overlayed over the source connected -to the pad with identifier "in". +@section amovie -@example -"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]" -@end example +This is the same as @ref{movie} source, except it selects an audio +stream by default. +@anchor{movie} @section movie -Read a video stream from a movie container. - -Note that this source is a hack that bypasses the standard input path. It can be -useful in applications that do not support arbitrary filter graphs, but its use -is discouraged in those that do. Specifically in @command{avconv} this filter -should never be used, the @option{-filter_complex} option fully replaces it. +Read audio and/or video stream(s) from a movie container. It accepts the syntax: @var{movie_name}[:@var{options}] where @var{movie_name} is the name of the resource to read (not necessarily @@ -2345,11 +7221,27 @@ starting from this seek point, the parameter is evaluated with @code{av_strtod} so the numerical value may be suffixed by an IS postfix. Default value is "0". +@item streams, s +Specifies the streams to read. Several streams can be specified, +separated by "+". The source will then have as many outputs, in the +same order. The syntax is explained in the ``Stream specifiers'' +section in the ffmpeg manual. Two special names, "dv" and "da" specify +respectively the default (best suited) video and audio stream. Default +is "dv", or "da" if the filter is called as "amovie". + @item stream_index, si Specifies the index of the video stream to read. If the value is -1, the best suited video stream will be automatically selected. Default -value is "-1". +value is "-1". Deprecated. If the filter is called "amovie", it will select +audio instead of video. + +@item loop +Specifies how many times to read the stream in sequence. +If the value is less than 1, the stream will be read again and again. +Default value is "1". +Note that when the movie is looped the source timestamps are not +changed, so it will generate non monotonically increasing timestamps. @end table This filter allows to overlay a second video on top of main input of @@ -2361,141 +7253,34 @@ input -----------> deltapts0 --> overlay --> output movie --> scale--> deltapts1 -------+ @end example -Some examples follow: -@example -# skip 3.2 seconds from the start of the avi file in.avi, and overlay it -# on top of the input labelled as "in". -movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie]; -[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] - -# read from a video4linux2 device, and overlay it on top of the input -# labelled as "in" -movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; -[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] - -@end example - -@section nullsrc - -Null video source, never return images. It is mainly useful as a -template and to be employed in analysis / debugging tools. - -It accepts as optional parameter a string of the form -@var{width}:@var{height}:@var{timebase}. - -@var{width} and @var{height} specify the size of the configured -source. The default values of @var{width} and @var{height} are -respectively 352 and 288 (corresponding to the CIF size format). - -@var{timebase} specifies an arithmetic expression representing a -timebase. The expression can contain the constants "PI", "E", "PHI", -"AVTB" (the default timebase), and defaults to the value "AVTB". - -@section frei0r_src - -Provide a frei0r source. - -To enable compilation of this filter you need to install the frei0r -header and configure Libav with --enable-frei0r. - -This source accepts the following options: - -@table @option - -@item size -The size of the video to generate, may be a string of the form -@var{width}x@var{height} or a frame size abbreviation. - -@item framerate -Framerate of the generated video, may be a string of the form -@var{num}/@var{den} or a frame rate abbreviation. - -@item filter_name -The name to the frei0r source to load. For more information regarding frei0r and -how to set the parameters read the section @ref{frei0r} in the description of -the video filters. - -@item filter_params -A '|'-separated list of parameters to pass to the frei0r source. - -@end table +@subsection Examples -Some examples follow: +@itemize +@item +Skip 3.2 seconds from the start of the avi file in.avi, and overlay it +on top of the input labelled as "in": @example -# generate a frei0r partik0l source with size 200x200 and framerate 10 -# which is overlayed on the overlay filter main input -frei0r_src=size=200x200:framerate=10:filter_name=partik0l:filter_params=1234 [overlay]; [in][overlay] overlay +movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [over]; +[in] setpts=PTS-STARTPTS [main]; +[main][over] overlay=16:16 [out] @end example -@section rgbtestsrc, testsrc - -The @code{rgbtestsrc} source generates an RGB test pattern useful for -detecting RGB vs BGR issues. You should see a red, green and blue -stripe from top to bottom. - -The @code{testsrc} source generates a test video pattern, showing a -color pattern, a scrolling gradient and a timestamp. This is mainly -intended for testing purposes. - -Both sources accept an optional sequence of @var{key}=@var{value} pairs, -separated by ":". The description of the accepted options follows. - -@table @option - -@item size, s -Specify the size of the sourced video, it may be a string of the form -@var{width}x@var{height}, or the name of a size abbreviation. The -default value is "320x240". - -@item rate, r -Specify the frame rate of the sourced video, as the number of frames -generated per second. It has to be a string in the format -@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float -number or a valid video frame rate abbreviation. The default value is -"25". - -@item sar -Set the sample aspect ratio of the sourced video. - -@item duration -Set the video duration of the sourced video. The accepted syntax is: +@item +Read from a video4linux2 device, and overlay it on top of the input +labelled as "in": @example -[-]HH[:MM[:SS[.m...]]] -[-]S+[.m...] +movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [over]; +[in] setpts=PTS-STARTPTS [main]; +[main][over] overlay=16:16 [out] @end example -See also the function @code{av_parse_time()}. - -If not specified, or the expressed duration is negative, the video is -supposed to be generated forever. -@end table -For example the following: +@item +Read the first video stream and the audio stream with id 0x81 from +dvd.vob; the video is connected to the pad named "video" and the audio is +connected to the pad named "audio": @example -testsrc=duration=5.3:size=qcif:rate=10 +movie=dvd.vob:s=v:0+#0x81 [video] [audio] @end example +@end itemize -will generate a video with a duration of 5.3 seconds, with size -176x144 and a framerate of 10 frames per second. - -@c man end VIDEO SOURCES - -@chapter Video Sinks -@c man begin VIDEO SINKS - -Below is a description of the currently available video sinks. - -@section buffersink - -Buffer video frames, and make them available to the end of the filter -graph. - -This sink is intended for a programmatic use through the interface defined in -@file{libavfilter/buffersink.h}. - -@section nullsink - -Null video sink, do absolutely nothing with the input video. It is -mainly useful as a template and to be employed in analysis / debugging -tools. - -@c man end VIDEO SINKS +@c man end MULTIMEDIA SOURCES