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diff --git a/ffmpeg1/doc/filters.texi b/ffmpeg1/doc/filters.texi deleted file mode 100644 index 74a682a..0000000 --- a/ffmpeg1/doc/filters.texi +++ /dev/null @@ -1,7034 +0,0 @@ -@chapter Filtering Introduction -@c man begin FILTERING INTRODUCTION - -Filtering in FFmpeg is enabled through the libavfilter library. - -In libavfilter, it is possible for filters to have multiple inputs and -multiple outputs. -To illustrate the sorts of things that are possible, we can -use a complex filter graph. For example, the following one: - -@example -input --> split ---------------------> overlay --> output - | ^ - | | - +-----> crop --> vflip -------+ -@end example - -splits the 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 "[in] split [T1], [T2] overlay=0:H/2 [out]; [T1] crop=iw:ih/2:0:ih/2, vflip [T2]" output -@end example - -The result will be that in output the top half of the video is mirrored -onto the bottom half. - -Filters are loaded using the @var{-vf} or @var{-af} option passed to -@command{ffmpeg} or to @command{ffplay}. Filters in the same linear -chain are separated by commas. In our example, @var{split, -overlay} are in one linear chain, and @var{crop, vflip} are in -another. The points where the linear chains join are labeled by names -enclosed in square brackets. In our example, that is @var{[T1]} and -@var{[T2]}. The special labels @var{[in]} and @var{[out]} are the points -where video is input and output. - -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 filter graph 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 filter graph. - -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 - -A filtergraph is a directed graph of connected filters. It can contain -cycles, and there can be multiple links between a pair of -filters. Each link has one input pad on one side connecting it to one -filter from which it takes its input, and one output pad on the other -side connecting it to the one filter accepting its output. - -Each filter in a filtergraph is an instance of a filter class -registered in the application, which defines the features and the -number of input and output pads of the filter. - -A filter with no input pads is called a "source", a filter with no -output pads is called a "sink". - -@anchor{Filtergraph syntax} -@section Filtergraph syntax - -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{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}. - -A filterchain consists of a sequence of connected filters, each one -connected to the previous one in the sequence. A filterchain is -represented by a list of ","-separated filter descriptions. - -A filtergraph consists of a sequence of filterchains. A sequence of -filterchains is represented by a list of ";"-separated filterchain -descriptions. - -A filter is represented by a string of the form: -[@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}] - -@var{filter_name} is the name of the filter class of which the -described filter is an instance of, and has to be the name of one of -the filter classes registered in the program. -The name of the filter class is optionally followed by a string -"=@var{arguments}". - -@var{arguments} is a string which contains the parameters used to -initialize the filter instance, and are described in the filter -descriptions below. - -The list of arguments can be quoted using the character "'" as initial -and ending mark, and the character '\' for escaping the characters -within the quoted text; otherwise the argument string is considered -terminated when the next special character (belonging to the set -"[]=;,") is encountered. - -The name and arguments of the filter are optionally preceded and -followed by a list of link labels. -A link label allows to name a link and associate it to a filter output -or input pad. The preceding labels @var{in_link_1} -... @var{in_link_N}, are associated to the filter input pads, -the following labels @var{out_link_1} ... @var{out_link_M}, are -associated to the output pads. - -When two link labels with the same name are found in the -filtergraph, a link between the corresponding input and output pad is -created. - -If an output pad is not labelled, it is linked by default to the first -unlabelled input pad of the next filter in the filterchain. -For example in the filterchain: -@example -nullsrc, split[L1], [L2]overlay, nullsink -@end example -the split filter instance has two output pads, and the overlay filter -instance two input pads. The first output pad of split is labelled -"L1", the first input pad of overlay is labelled "L2", and the second -output pad of split is linked to the second input pad of overlay, -which are both unlabelled. - -In a complete filterchain all the unlabelled filter input and output -pads must be connected. A filtergraph is considered valid if all the -filter input and output pads of all the filterchains are connected. - -Libavfilter will automatically insert scale filters where format -conversion is required. It is possible to specify swscale flags -for those automatically inserted scalers by prepending -@code{sws_flags=@var{flags};} -to the filtergraph description. - -Follows a BNF description for the filtergraph syntax: -@example -@var{NAME} ::= sequence of alphanumeric characters and '_' -@var{LINKLABEL} ::= "[" @var{NAME} "]" -@var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}] -@var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted) -@var{FILTER} ::= [@var{LINKLABELS}] @var{NAME} ["=" @var{FILTER_ARGUMENTS}] [@var{LINKLABELS}] -@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}] -@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 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 - -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: -@table @option - -@item sample_fmts -A comma-separated list of requested sample formats. - -@item sample_rates -A comma-separated list of requested sample rates. - -@item channel_layouts -A comma-separated list of requested channel layouts. - -@end table - -If a parameter is omitted, all values are allowed. - -For example to force the output to either unsigned 8-bit or signed 16-bit stereo: -@example -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 -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. - -The filter accepts the following named parameters: -@table @option - -@item inputs -Number of inputs. If unspecified, it defaults to 2. - -@item duration -How to determine the end-of-stream. -@table @option - -@item longest -Duration of longest input. (default) - -@item shortest -Duration of shortest input. - -@item first -Duration of first input. - -@end table - -@item dropout_transition -Transition time, in seconds, for volume renormalization when an input -stream ends. The default value is 2 seconds. - -@end table - -@section anull - -Pass the audio source unchanged to the output. - -@section apad - -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. - -@anchor{aresample} -@section aresample - -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. - -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. - -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. - -@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 - -@item rate -sample rate for the audio frame - -@item nb_samples -number of samples (per channel) in the frame - -@item checksum -Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio -the data is treated as if all the planes were concatenated. - -@item plane_checksums -A list of Adler-32 checksums for each data plane. -@end table - -@section asplit - -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: -@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 -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 - -@item compensate -Enable stretching/squeezing the data to make it match the timestamps. Disabled -by default. When disabled, time gaps are covered with silence. - -@item min_delta -Minimum difference between timestamps and audio data (in seconds) to trigger -adding/dropping samples. Default value is 0.1. If you get non-perfect sync with -this filter, try setting this parameter to 0. - -@item max_comp -Maximum compensation in samples per second. Relevant only with compensate=1. -Default value 500. - -@item first_pts -Assume the first pts should be this value. The time base is 1 / sample rate. -This allows for padding/trimming at the start of stream. By default, no -assumption is made about the first frame's expected pts, so no padding or -trimming is done. For example, this could be set to 0 to pad the beginning with -silence if an audio stream starts after the video stream or to trim any samples -with a negative pts due to encoder delay. - -@end table - -@section channelsplit -Split each channel in input audio stream into a separate output stream. - -This filter accepts the following named parameters: -@table @option -@item channel_layout -Channel layout of the input stream. Default is "stereo". -@end table - -For example, assuming a stereo input MP3 file -@example -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 -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]' -side_right.wav -@end example - -@section channelmap -Remap input channels to new locations. - -This filter accepts the following named parameters: -@table @option -@item channel_layout -Channel layout of the output stream. - -@item map -Map channels from input to output. The argument is a comma-separated list of -mappings, each in the @code{@var{in_channel}-@var{out_channel}} or -@var{in_channel} form. @var{in_channel} can be either the name of the input -channel (e.g. FL for front left) or its index in the input channel layout. -@var{out_channel} is the name of the output channel or its index in the output -channel layout. If @var{out_channel} is not given then it is implicitly an -index, starting with zero and increasing by one for each mapping. -@end table - -If no mapping is present, the filter will implicitly map input channels to -output channels preserving index. - -For example, assuming a 5.1+downmix input MOV file -@example -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 -ffmpeg -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav -@end example - -@section join -Join multiple input streams into one multi-channel stream. - -The filter accepts the following named parameters: -@table @option - -@item inputs -Number of input streams. Defaults to 2. - -@item channel_layout -Desired output channel layout. Defaults to stereo. - -@item map -Map channels from inputs to output. The argument is a comma-separated list of -mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}} -form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel} -can be either the name of the input channel (e.g. FL for front left) or its -index in the specified input stream. @var{out_channel} is the name of the output -channel. -@end table - -The filter will attempt to guess the mappings when those are not specified -explicitly. It does so by first trying to find an unused matching input channel -and if that fails it picks the first unused input channel. - -E.g. to join 3 inputs (with properly set channel layouts) -@example -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 -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. - -@section volume - -Adjust the input audio volume. - -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 -Expresses how the audio volume will be increased or decreased. - -Output values are clipped to the maximum value. - -The output audio volume is given by the relation: -@example -@var{output_volume} = @var{volume} * @var{input_volume} -@end example - -Default value for @var{volume} is 1.0. - -@item precision -Set the mathematical precision. - -This determines which input sample formats will be allowed, which affects the -precision of the volume scaling. - -@table @option -@item fixed -8-bit fixed-point; limits input sample format to U8, S16, and S32. -@item float -32-bit floating-point; limits input sample format to FLT. (default) -@item double -64-bit floating-point; limits input sample format to DBL. -@end table -@end table - -@subsection Examples - -@itemize -@item -Halve the input audio volume: -@example -volume=volume=0.5 -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 -volume=volume=6dB:precision=fixed -@end example -@end itemize - -@section volumedetect - -Detect the volume of the input video. - -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. - -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. - -@subsection Examples - -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 - -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 - -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. - -@c man end AUDIO FILTERS - -@chapter Audio Sources -@c man begin AUDIO SOURCES - -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 mainly intended for a programmatic use, in particular -through the interface defined in @file{libavfilter/asrc_abuffer.h}. - -It accepts the following mandatory parameters: -@var{sample_rate}:@var{sample_fmt}:@var{channel_layout} - -@table @option - -@item sample_rate -The sample rate of the incoming audio buffers. - -@item sample_fmt -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 -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 - -@subsection Examples - -@example -abuffer=44100:s16p:stereo -@end example - -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 - -@section aevalsrc - -Generate an audio signal specified by an expression. - -This source accepts in input one or more expressions (one for each -channel), which are evaluated and used to generate a corresponding -audio signal. - -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. - -@var{options} is an optional sequence of @var{key}=@var{value} pairs, -separated by ":". - -The description of the accepted options follows. - -@table @option - -@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. - -@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. - -If not specified, or the expressed duration is negative, the audio is -supposed to be generated forever. - -@item nb_samples, n -Set the number of samples per channel per each output frame, -default to 1024. - -@item sample_rate, s -Specify the sample rate, default to 44100. -@end table - -Each expression in @var{exprs} can contain the following constants: - -@table @option -@item n -number of the evaluated sample, starting from 0 - -@item t -time of the evaluated sample expressed in seconds, starting from 0 - -@item s -sample rate - -@end table - -@subsection Examples - -@itemize -@item -Generate silence: -@example -aevalsrc=0 -@end example - -@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 - -@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 -Generate white noise: -@example -aevalsrc="-2+random(0)" -@end example - -@item -Generate an amplitude modulated signal: -@example -aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)" -@end example - -@item -Generate 2.5 Hz binaural beats on a 360 Hz carrier: -@example -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 anullsrc - -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). - -It accepts an optional sequence of @var{key}=@var{value} pairs, -separated by ":". - -The description of the accepted options follows. - -@table @option - -@item sample_rate, s -Specify the sample rate, and defaults to 44100. - -@item channel_layout, cl - -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". - -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 - -@subsection Examples - -@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 -Do the same operation with a more obvious syntax: -@example -anullsrc=r=48000:cl=mono -@end example -@end itemize - -@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}. - -It accepts the following named parameters: -@table @option - -@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 sample_rate -Audio sample rate. - -@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 - -All the parameters need to be explicitly defined. - -@section flite - -Synthesize a voice utterance using the libflite library. - -To enable compilation of this filter you need to configure FFmpeg with -@code{--enable-libflite}. - -Note that the flite library is not thread-safe. - -The source accepts parameters as a list of @var{key}=@var{value} pairs, -separated by ":". - -The description of the accepted parameters follows. - -@table @option - -@item list_voices -If set to 1, list the names of the available voices and exit -immediately. Default value is 0. - -@item nb_samples, n -Set the maximum number of samples per frame. Default value is 512. - -@item textfile -Set the filename containing the text to speak. - -@item text -Set the text to speak. - -@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 - -@subsection Examples - -@itemize -@item -Read from file @file{speech.txt}, and synthetize the text using the -standard flite voice: -@example -flite=textfile=speech.txt -@end example - -@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 - -@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 - -@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 - -For more information about libflite, check: -@url{http://www.speech.cs.cmu.edu/flite/} - -@section sine - -Generate an audio signal made of a sine wave with amplitude 1/8. - -The audio signal is bit-exact. - -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. - -The supported options are: - -@table @option - -@item frequency, f -Set the carrier frequency. Default is 440 Hz. - -@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 sample_rate, s -Specify the sample rate, default is 44100. - -@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 - -@subsection Examples - -@itemize - -@item -Generate a simple 440 Hz sine wave: -@example -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 - -@c man end AUDIO SOURCES - -@chapter Audio Sinks -@c man begin AUDIO SINKS - -Below is a description of the currently available audio sinks. - -@section abuffersink - -Buffer audio frames, and make them available to the end of filter chain. - -This sink is mainly intended for programmatic use, in particular -through the interface defined in @file{libavfilter/buffersink.h}. - -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. - -@section anullsink - -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 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}. - -This filter accepts no parameters. - -@c man end AUDIO SINKS - -@chapter Video Filters -@c man begin VIDEO 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 video filters included in your -build. - -Below is a description of the currently available video filters. - -@section alphaextract - -Extract the alpha component from the input as a grayscale video. This -is especially useful with the @var{alphamerge} filter. - -@section alphamerge - -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. - -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 - -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. - -@section ass - -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. - -@section bbox - -Compute the bounding box for the non-black pixels in the input frame -luminance plane. - -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. - -@section blackdetect - -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. - -In order to display the output lines, you need to set the loglevel at -least to the AV_LOG_INFO value. - -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 black_min_duration, d -Set the minimum detected black duration expressed in seconds. It must -be a non-negative floating point number. - -Default value is 2.0. - -@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 - -for which a picture is considered black. -Default value is 0.98. - -@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}]]. - -A description of the accepted options follows. - -@table @option -@item amount -Set the percentage of pixels that have to be below the -threshold to enable black detection. Default value is 98. - -@item threshold -Set the threshold below which a pixel value is considered -black. Default value is 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_expr}. 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 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}. - -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=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=min(h\,w)/10:1:min(cw\,ch)/10:1 -@end example -@end itemize - -@section colormatrix - -The colormatrix filter allows conversion between any of the following color -space: BT.709 (@var{bt709}), BT.601 (@var{bt601}), SMPTE-240M (@var{smpte240m}) -and FCC (@var{fcc}). - -The syntax of the parameters is @var{source}:@var{destination}: - -@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. - -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 -Set the crop area width. It defaults to @code{iw}. -This expression is evaluated only once during the filter -configuration. - -@item h, out_h -Set the crop area width. It defaults to @code{ih}. -This expression is evaluated only once during the filter -configuration. - -@item x -Set the expression for the x top-left coordinate of the cropped area. -It defaults to @code{(in_w-out_w)/2}. -This expression is evaluated per-frame. - -@item y -Set the expression for the y top-left coordinate of the cropped area. -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=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 ":". - -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. -@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 -@end itemize - -@section decimate - -Drop frames that do not differ greatly from the previous frame in -order to reduce framerate. - -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). - -The filter accepts parameters as a string of the form -"@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of -@var{key}=@var{value} pairs, separated by ":". - -The description of the accepted parameters follows. - -@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=0:0:100:77:10 -@end example - -@item -As the previous example, but use named options: -@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}. - -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. - -@end table - -@section drawbox - -Draw a colored box on the input image. - -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{x}:@option{y}:@option{width}:@option{height}:@option{color}:@option{thickness}. - -A description of the accepted options follows. - -@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 filter accepts parameters as a list of @var{key}=@var{value} pairs, -separated by ":". - -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 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 filter graph 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. - -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{type}:@var{start_frame}:@var{nb_frames}. - -A description of the accepted parameters follows. - -@table @option -@item type, t -Specify if 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_frame, s -Specify the number of the start frame for starting to apply the fade -effect. Default is 0. - -@item nb_frames, n -Specify 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 -@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 named option @option{order} which -specifies the required field order that the input interlaced video -will be transformed to. The option name can be omitted. - -The option @option{order} can assume one of the following values: -@table @samp -@item bff -output bottom field first -@item tff -output top 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. - -The filter accepts a list of pixel format names, separated by ":", -for example "yuv420p:monow:rgb24". - -@subsection Examples - -@itemize -@item -Convert the input video to the format @var{yuv420p} -@example -format=yuv420p -@end example - -Convert the input video to any of the formats in the list -@example -format=yuv420p:yuv444p:yuv410p -@end example -@end itemize - -@section fps - -Convert the video to specified constant framerate by duplicating or dropping -frames as necessary. - -This filter accepts the following named parameters: -@table @option - -@item fps -Desired output framerate. 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}. - -The filter supports the syntax: -@example -@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}] -@end example - -@var{filter_name} is the name of 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 (or -semicolon on Windows platforms) 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/}. - -@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters -for the frei0r effect. - -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=distort0r: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, Y -The coordinates of the current sample. - -@item W, H -The width and height of the image. - -@item SW, 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. - -The 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 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 @code{0.51} to @code{64}, default value -is @code{1.2}. - -@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 -@code{8-32}, default value is @code{16}. - -@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: -@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp} - -@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. - -The filter accepts a list of pixel format names, separated by ":", -for example "yuv420p:monow:rgb24". - -@subsection Examples - -@itemize -@item -Force libavfilter to use a format different from @var{yuv420p} for the -input to the vflip filter: -@example -noformat=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}. - -The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}. - -@var{filter_name} is the name of the libopencv filter to apply. - -@var{filter_params} specifies the parameters to pass to the libopencv -filter. If not specified the default values are assumed. - -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=dilate=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=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, y -Set the expression for the x and y coordinates of the overlayed video -on the main video. Default value is 0. - -The @var{x} and @var{y} expressions can contain the following -parameters: -@table @option -@item main_w, main_h -main input width and height - -@item W, H -same as @var{main_w} and @var{main_h} - -@item overlay_w, overlay_h -overlay input width and height - -@item w, h -same as @var{overlay_w} and @var{overlay_h} -@end table - -@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. - -@item shortest -If set to 1, force the output to terminate when the shortest input -terminates. Default value is 0. -@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. - -You can chain together more overlays but you should test the -efficiency of such approach. - -@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, WxH specifies -the size of the main input to the overlay filter: -@example -color=red@@.3: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 -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 -Set the video width expression, default value is @code{iw}. See below -for the list of accepted constants. - -@item height, h -Set the video heiht expression, 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{width} or @var{height} is 0, the respective input -size is used for the output. - -If the value for @var{width} or @var{height} 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=200:100 -@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=2*iw: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=iw/2: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=3/2*oh:3/5*ih -@end example - -@item -Increase the size, but make the size a multiple of the chroma: -@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='min(500\, iw*3/2):-1' -@end example -@end itemize - -@section setdar, setsar - -The @code{setdar} filter sets the Display Aspect Ratio for the filter -output video. - -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 - -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. - -The @code{setsar} filter sets 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 equation -above. - -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. - -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: -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 - -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 -setdar='16:9' -@end example - -The example above is equivalent to: -@example -setdar=1.77777 -@end example - -To change the sample aspect ratio to 10:11, specify: -@example -setsar='10:11' -@end example - -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 -setdar=ratio='16:9':max=1000 -@end example - -@section setfield - -Force field for the output video frame. - -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}). - -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: - -@table @samp -@item auto -Keep the same field property. - -@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 -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 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 - -@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 - -If a chroma option is not explicitly set, the corresponding luma value -is set. - -@section stereo3d - -Convert between different stereoscopic image formats. - -This filter accepts the following named options, expressed as a -sequence of @var{key}=@var{value} pairs, separated by ":". - -@table @option -@item in -Set stereoscopic image format of input. - -Available values for input image formats are: -@table @samp -@item sbsl -side by side parallel (left eye left, right eye right) - -@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 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 - -If the first key is not specified, it is assumed that the first value -specifies the @option{filename}. - -For example, to render the file @file{sub.srt} on top of the input -video, use the command: -@example -subtitles=sub.srt -@end example - -which is equivalent to: -@example -subtitles=filename=sub.srt -@end example - -@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 -[in] split [splitout1][splitout2]; -[splitout1] crop=100:100:0:0 [cropout]; -[splitout2] pad=200:200:100:100 [padout]; -@end example - -will create two separate outputs from the same input, one cropped and -one padded. - -@section super2xsai - -Scale the input by 2x and smooth using the Super2xSaI (Scale and -Interpolate) pixel art scaling algorithm. - -Useful for enlarging pixel art images without reducing sharpness. - -@section swapuv -Swap U & V plane. - -@section thumbnail -Select the most representative frame in a given sequence of consecutive frames. - -It accepts as argument the frames batch size to analyze (default @var{N}=100); -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. - -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. - -The following example extract one picture each 50 frames: -@example -thumbnail=50 -@end example - -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 - -@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 - -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 -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. - -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 tinterlace - -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. - -@table @option - -@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 framerate. - -@item drop_odd, 1 -Only output even frames, odd frames are dropped, generating a frame with -unchanged height at half framerate. - -@item drop_even, 2 -Only output odd frames, even frames are dropped, generating a frame with -unchanged height at half framerate. - -@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 framerate. - -@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 framerate. - -@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 framerate. - -@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 - -@section transpose - -Transpose rows with columns in the input video and optionally flip it. - -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: - -@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 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 - -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. - -@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 - -Default value is @code{none}. -@end table - -For example to rotate by 90 degrees clockwise and preserve portrait -layout: -@example -transpose=dir=1:passthrough=portrait -@end example - -The command above can also be specified as: -@example -transpose=1:portrait -@end example - -@section unsharp - -Sharpen or blur the input video. - -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_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount} - -A description of the accepted options follows. - -@table @option -@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 -unsharp=7:7:2.5 -@end example - -@item -Apply strong blur of both luma and chroma parameters: -@example -unsharp=7:7:-2:7:7:-2 -@end example -@end itemize - -@section vflip - -Flip the input video vertically. - -@example -ffmpeg -i in.avi -vf "vflip" out.avi -@end example - -@section yadif - -Deinterlace the input video ("yadif" means "yet another deinterlacing -filter"). - -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}. - -The description of the accepted parameters follows. - -@table @option -@item mode -Specify the interlacing mode to adopt. Accept one of the following -values: - -@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 - -Default value is @code{send_frame}. - -@item parity -Specify the picture field parity assumed for the input interlaced -video. Accept one of the following values: - -@table @option -@item 0, tff -assume top field first -@item 1, bff -assume bottom field first -@item -1, auto -enable automatic detection -@end table - -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: - -@table @option -@item 0, all -deinterlace all frames -@item 1, interlaced -only deinterlace frames marked as interlaced -@end table - -Default value is @code{all}. -@end table - -@c man end VIDEO FILTERS - -@chapter Video Sources -@c man begin VIDEO SOURCES - -Below is a description of the currently available video sources. - -@section buffer - -Buffer video frames, and make them available to the filter chain. - -This source is mainly intended for a programmatic use, in particular -through the interface defined in @file{libavfilter/vsrc_buffer.h}. - -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 video_size -Specify the size (width and height) of the buffered video frames. - -@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 - -For example: -@example -buffer=size=320x240:pix_fmt=yuv410p:time_base=1/24:pixel_aspect=1/1 -@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). -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 -buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1 -@end example - -Alternatively, the options can be specified as a flat string, but this -syntax is deprecated: - -@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}] - -@section cellauto - -Create a pattern generated by an elementary cellular automaton. - -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. - -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. - -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 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. - -@item pattern, p -Read the initial cellular automaton state, i.e. the starting row, from -the specified string. - -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. - -@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 cellular automaton row. It -is a floating point number value ranging from 0 to 1, defaults to -1/PHI. - -This option is ignored when a file or a pattern is specified. - -@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 - -@subsection Examples - -@itemize -@item -Read the initial state from @file{pattern}, and specify an output of -size 200x400. -@example -cellauto=f=pattern:s=200x400 -@end example - -@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 - -@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 - -@item -Specify a more elaborated initial pattern: -@example -cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18 -@end example - -@end itemize - -@section mandelbrot - -Generate a Mandelbrot set fractal, and progressively zoom towards the -point specified with @var{start_x} and @var{start_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. - -@table @option - -@item end_pts -Set the terminal pts value. Default value is 400. - -@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 - -Default value is @var{mincol}. - -@item bailout -Set the bailout value. Default value is 10.0. - -@item maxiter -Set the maximum of iterations performed by the rendering -algorithm. Default value is 7189. - -@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}. - -@item rate, r -Set frame rate, expressed as number of frames per second. Default -value is "25". - -@item size, s -Set frame size. Default value is "640x480". - -@item start_scale -Set the initial scale value. Default value is 3.0. - -@item start_x -Set the initial x position. Must be a floating point value between --100 and 100. Default value is -0.743643887037158704752191506114774. - -@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 - -@section mptestsrc - -Generate various test patterns, as generated by the MPlayer test filter. - -The size of the generated video is fixed, and is 256x256. -This source is useful in particular for testing encoding features. - -This source accepts an optional sequence of @var{key}=@var{value} pairs, -separated by ":". The description of the accepted options follows. - -@table @option - -@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 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()}. - -If not specified, or the expressed duration is negative, the video is -supposed to be generated forever. - -@item test, t - -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 - -Default value is "all", which will cycle through the list of all tests. -@end table - -For example the following: -@example -testsrc=t=dc_luma -@end example - -will generate a "dc_luma" test pattern. - -@section frei0r_src - -Provide a frei0r source. - -To enable compilation of this filter you need to install the frei0r -header and configure FFmpeg with @code{--enable-frei0r}. - -The source supports the syntax: -@example -@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}] -@end example - -@var{size} is the size of the video to generate, may be a string of the -form @var{width}x@var{height} or a frame size abbreviation. -@var{rate} is the rate of the video to generate, may be a string of -the form @var{num}/@var{den} or a frame rate abbreviation. -@var{src_name} is 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. - -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 -frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay -@end example - -@section life - -Generate a life pattern. - -This source is based on a generalization of John Conway's life game. - -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. - -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. - -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 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. - -If this option is not specified, the initial grid is generated -randomly. - -@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 size, s -Set the size of the output video. - -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. - -If a filename is not specified, the size value defaults to "320x240" -(used for a randomly generated initial grid). - -@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 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 life_color -Set the color of living (or new born) cells. - -@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 - -@subsection Examples - -@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 - -@item -Generate a random grid of size 200x200, with a fill ratio of 2/3: -@example -life=ratio=2/3:s=200x200 -@end example - -@item -Specify a custom rule for evolving a randomly generated grid: -@example -life=rule=S14/B34 -@end example - -@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 - -@section color, nullsrc, rgbtestsrc, smptebars, testsrc - -The @code{color} source provides an uniformly colored input. - -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 @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{smptebars} source generates a color bars pattern, based on -the SMPTE Engineering Guideline EG 1-1990. - -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. - -These sources accept an optional sequence of @var{key}=@var{value} pairs, -separated by ":". The description of the accepted options follows. - -@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". - -@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 -[-]HH[:MM[:SS[.m...]]] -[-]S+[.m...] -@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. - -@item decimals, n -Set the number of decimals to show in the timestamp, only used in the -@code{testsrc} source. - -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 - -For example the following: -@example -testsrc=duration=5.3:size=qcif:rate=10 -@end example - -will generate a video with a duration of 5.3 seconds, with size -176x144 and a frame rate of 10 frames per second. - -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 - -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 -nullsrc=s=256x256, geq=random(1)*255:128:128 -@end example - -@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 mainly intended for a programmatic use, in particular -through the interface defined in @file{libavfilter/buffersink.h}. - -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. - -@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 - -@chapter Multimedia Filters -@c man begin MULTIMEDIA FILTERS - -Below is a description of the currently available multimedia filters. - -@section aperms, perms - -Set read/write permissions for the output frames. - -These filters are mainly aimed at developers to test direct path in the -following filter in the filtergraph. - -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}. - -A description of the accepted parameters follows. - -@table @option -@item mode -Select the permissions mode. - -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 -@end table - -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. - -@section aselect, select -Select frames to pass in output. - -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 n -the sequential number of the filtered frame, starting from 0 - -@item selected_n -the sequential number of the selected frame, starting from 0 - -@item prev_selected_n -the sequential number of the last selected frame, NAN if undefined - -@item TB -timebase of the input timestamps - -@item pts -the PTS (Presentation TimeStamp) of the filtered video frame, -expressed in @var{TB} units, NAN if undefined - -@item t -the PTS (Presentation TimeStamp) of the filtered video frame, -expressed in seconds, NAN if undefined - -@item prev_pts -the PTS of the previously filtered video frame, NAN if undefined - -@item prev_selected_pts -the PTS of the last previously filtered video frame, NAN if undefined - -@item prev_selected_t -the PTS of the last previously selected video frame, NAN if undefined - -@item start_pts -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 @emph{(video only)} -the type of the filtered frame, can assume one of the following -values: -@table @option -@item I -@item P -@item B -@item S -@item SI -@item SP -@item BI -@end table - -@item interlace_type @emph{(video only)} -the frame interlace type, can assume one of the following values: -@table @option -@item PROGRESSIVE -the frame is progressive (not interlaced) -@item TOPFIRST -the frame is top-field-first -@item BOTTOMFIRST -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". - -@subsection Examples - -@itemize -@item -Select all frames in input: -@example -select -@end example - -The example above is the same as: -@example -select=1 -@end example - -@item -Skip all frames: -@example -select=0 -@end example - -@item -Select only I-frames: -@example -select='eq(pict_type\,I)' -@end example - -@item -Select one frame every 100: -@example -select='not(mod(n\,100))' -@end example - -@item -Select only frames contained in the 10-20 time interval: -@example -select='gte(t\,10)*lte(t\,20)' -@end example - -@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 - -@item -Select frames with a minimum distance of 10 seconds: -@example -select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)' -@end example - -@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 - -Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane -choice. -@end itemize - -@section asendcmd, sendcmd - -Send commands to filters in the filtergraph. - -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 - -@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 - -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 -@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 - -@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 - -@anchor{setpts} -@section asetpts, setpts - -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 N -the count of the input frame, starting from 0. - -@item NB_CONSUMED_SAMPLES -the number of consumed samples, not including the current frame (only -audio) - -@item NB_SAMPLES -the number of samples in the current frame (only audio) - -@item SAMPLE_RATE -audio sample rate - -@item STARTPTS -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. This is deprecated, use time(0) -instead. - -@item RTCSTART -wallclock (RTC) time at the start of the movie in microseconds -@end table - -@subsection Examples - -@itemize -@item -Start counting PTS from zero -@example -setpts=PTS-STARTPTS -@end example - -@item -Apply fast motion effect: -@example -setpts=0.5*PTS -@end example - -@item -Apply slow motion effect: -@example -setpts=2.0*PTS -@end example - -@item -Set fixed rate of 25 frames per second: -@example -setpts=N/(25*TB) -@end example - -@item -Set fixed rate 25 fps with some jitter: -@example -setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))' -@end example - -@item -Apply an offset of 10 seconds to the input PTS: -@example -setpts=PTS+10/TB -@end example - -@item -Generate timestamps from a "live source" and rebase onto the current timebase: -@example -setpts='(RTCTIME - RTCSTART) / (TB * 1000000)' -@end example -@end itemize - -@section ebur128 - -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}). - -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). - -More information about the Loudness Recommendation EBU R128 on -@url{http://tech.ebu.ch/loudness}. - -The filter accepts the following named parameters: - -@table @option - -@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 size -Set the video size. This option is for video only. Default and minimum -resolution is @code{640x480}. - -@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 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.}. - -Default is @code{0}. - -@item framelog -Force the frame logging level. - -Available values are: -@table @samp -@item info -information logging level -@item verbose -verbose logging level -@end table - -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 - -@subsection Examples - -@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 - -@item -Run an analysis with @command{ffmpeg}: -@example -ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null - -@end example -@end itemize - -@section settb, asettb - -Set the timebase to use for the output frames timestamps. -It is mainly useful for testing timebase configuration. - -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 - -@itemize -@item -Set the timebase to 1/25: -@example -settb=1/25 -@end example - -@item -Set the timebase to 1/10: -@example -settb=0.1 -@end example - -@item -Set the timebase to 1001/1000: -@example -settb=1+0.001 -@end example - -@item -Set the timebase to 2*intb: -@example -settb=2*intb -@end example - -@item -Set the default timebase value: -@example -settb=AVTB -@end example -@end itemize - -@section concat - -Concatenate audio and video streams, joining them together one after the -other. - -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 n -Set the number of segments. Default is 2. - -@item v -Set the number of output video streams, that is also the number of video -streams in each segment. Default is 1. - -@item a -Set the number of output audio streams, that is also the number of video -streams in each segment. Default is 0. - -@item unsafe -Activate unsafe mode: do not fail if segments have a different format. - -@end table - -The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then -@var{a} audio outputs. - -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. - -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. - -For this filter to work correctly, all segments must start at timestamp 0. - -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. - -Different frame rates are acceptable but will result in variable frame rate -at output; be sure to configure the output file to handle it. - -@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 -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 - -@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. - -@end itemize - -@section showspectrum - -Convert input audio to a video output, representing the audio frequency -spectrum. - -The filter accepts the following named parameters: -@table @option -@item size, s -Specify the video size for the output. Default value is @code{640x512}. - -@item slide -Specify if the spectrum should slide along the window. Default value is -@code{0}. - -@item mode -Specify display mode. - -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 @samp{combined}. - -@item color -Specify display color mode. - -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 @samp{channel}. - -@item scale -Specify scale used for calculating intensity color values. - -It accepts the following values: -@table @samp -@item lin -linear -@item sqrt -square root, default -@item cbrt -cubic root -@item log -logarithmic -@end table - -Default value is @samp{sqrt}. - -@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 - -The usage is very similar to the showwaves filter; see the examples in that -section. - -@subsection Examples - -@itemize -@item -Large window with logarithmic color scaling: -@example -showspectrum=s=1280x480:scale=log -@end example - -@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 - -@section showwaves - -Convert input audio to a video output, representing the samples waves. - -The filter accepts the following named parameters: -@table @option -@item mode -Set display mode. - -Available values are: -@table @samp -@item point -Draw a point for each sample. - -@item line -Draw a vertical line for each sample. -@end table - -Default value is @code{point}. - -@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. - -@item rate, r -Set the (approximate) output frame rate. This is done by setting the -option @var{n}. Default value is "25". - -@item size, s -Specify the video size for the output. Default value is "600x240". -@end table - -@subsection Examples - -@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 -Create a synthetic signal and show it with showwaves, forcing a -framerate 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 - -@c man end MULTIMEDIA FILTERS - -@chapter Multimedia Sources -@c man begin MULTIMEDIA SOURCES - -Below is a description of the currently available multimedia sources. - -@section amovie - -This is the same as @ref{movie} source, except it selects an audio -stream by default. - -@anchor{movie} -@section movie - -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 -a file but also a device or a stream accessed through some protocol), -and @var{options} is an optional sequence of @var{key}=@var{value} -pairs, separated by ":". - -The description of the accepted options follows. - -@table @option - -@item format_name, f -Specifies the format assumed for the movie to read, and can be either -the name of a container or an input device. If not specified the -format is guessed from @var{movie_name} or by probing. - -@item seek_point, sp -Specifies the seek point in seconds, the frames will be output -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". 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 -a filtergraph as shown in this graph: -@example -input -----------> deltapts0 --> overlay --> output - ^ - | -movie --> scale--> deltapts1 -------+ -@end example - -@subsection Examples - -@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 -movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie]; -[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] -@end example - -@item -Read from a video4linux2 device, and overlay it on top of the input -labelled as "in": -@example -movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie]; -[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out] -@end example - -@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 -movie=dvd.vob:s=v:0+#0x81 [video] [audio] -@end example -@end itemize - -@c man end MULTIMEDIA SOURCES |