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diff --git a/ffmpeg/doc/filters.texi b/ffmpeg/doc/filters.texi deleted file mode 100644 index a579964..0000000 --- a/ffmpeg/doc/filters.texi +++ /dev/null @@ -1,10207 +0,0 @@ -@chapter Filtering Introduction -@c man begin FILTERING INTRODUCTION - -Filtering in FFmpeg is enabled through the libavfilter library. - -In libavfilter, a filter can have multiple inputs and multiple -outputs. -To illustrate the sorts of things that are possible, we consider the -following filtergraph. - -@example - [main] -input --> split ---------------------> overlay --> output - | ^ - |[tmp] [flip]| - +-----> crop --> vflip -------+ -@end example - -This filtergraph splits the input stream in two streams, sends one -stream through the crop filter and the vflip filter before merging it -back with the other stream by overlaying it on top. You can use the -following command to achieve this: - -@example -ffmpeg -i INPUT -vf "split [main][tmp]; [tmp] crop=iw:ih/2:0:0, vflip [flip]; [main][flip] overlay=0:H/2" OUTPUT -@end example - -The result will be that in output the top half of the video is mirrored -onto the bottom half. - -Filters in the same linear chain are separated by commas, and distinct -linear chains of filters are separated by semicolons. In our example, -@var{crop,vflip} are in one linear chain, @var{split} and -@var{overlay} are separately in another. The points where the linear -chains join are labelled by names enclosed in square brackets. In the -example, the split filter generates two outputs that are associated to -the labels @var{[main]} and @var{[tmp]}. - -The stream sent to the second output of @var{split}, labelled as -@var{[tmp]}, is processed through the @var{crop} filter, which crops -away the lower half part of the video, and then vertically flipped. The -@var{overlay} filter takes in input the first unchanged output of the -split filter (which was labelled as @var{[main]}), and overlay on its -lower half the output generated by the @var{crop,vflip} filterchain. - -Some filters take in input a list of parameters: they are specified -after the filter name and an equal sign, and are separated from each other -by a colon. - -There exist so-called @var{source filters} that do not have an -audio/video input, and @var{sink filters} that will not have audio/video -output. - -@c man end FILTERING INTRODUCTION - -@chapter graph2dot -@c man begin GRAPH2DOT - -The @file{graph2dot} program included in the FFmpeg @file{tools} -directory can be used to parse a filtergraph description and issue a -corresponding textual representation in the dot language. - -Invoke the command: -@example -graph2dot -h -@end example - -to see how to use @file{graph2dot}. - -You can then pass the dot description to the @file{dot} program (from -the graphviz suite of programs) and obtain a graphical representation -of the filtergraph. - -For example the sequence of commands: -@example -echo @var{GRAPH_DESCRIPTION} | \ -tools/graph2dot -o graph.tmp && \ -dot -Tpng graph.tmp -o graph.png && \ -display graph.png -@end example - -can be used to create and display an image representing the graph -described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be -a complete self-contained graph, with its inputs and outputs explicitly defined. -For example if your command line is of the form: -@example -ffmpeg -i infile -vf scale=640:360 outfile -@end example -your @var{GRAPH_DESCRIPTION} string will need to be of the form: -@example -nullsrc,scale=640:360,nullsink -@end example -you may also need to set the @var{nullsrc} parameters and add a @var{format} -filter in order to simulate a specific input file. - -@c man end GRAPH2DOT - -@chapter Filtergraph description -@c man begin FILTERGRAPH DESCRIPTION - -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/avfilter.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. It may have one of the following forms: -@itemize - -@item -A ':'-separated list of @var{key=value} pairs. - -@item -A ':'-separated list of @var{value}. In this case, the keys are assumed to be -the option names in the order they are declared. E.g. the @code{fade} filter -declares three options in this order -- @option{type}, @option{start_frame} and -@option{nb_frames}. Then the parameter list @var{in:0:30} means that the value -@var{in} is assigned to the option @option{type}, @var{0} to -@option{start_frame} and @var{30} to @option{nb_frames}. - -@item -A ':'-separated list of mixed direct @var{value} and long @var{key=value} -pairs. The direct @var{value} must precede the @var{key=value} pairs, and -follow the same constraints order of the previous point. The following -@var{key=value} pairs can be set in any preferred order. - -@end itemize - -If the option value itself is a list of items (e.g. the @code{format} filter -takes a list of pixel formats), the items in the list are usually separated by -'|'. - -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 @ref{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. - -@chapter Timeline editing - -Some filters support a generic @option{enable} option. For the filters -supporting timeline editing, this option can be set to an expression which is -evaluated before sending a frame to the filter. If the evaluation is non-zero, -the filter will be enabled, otherwise the frame will be sent unchanged to the -next filter in the filtergraph. - -The expression accepts the following values: -@table @samp -@item t -timestamp expressed in seconds, NAN if the input timestamp is unknown - -@item n -sequential number of the input frame, starting from 0 - -@item pos -the position in the file of the input frame, NAN if unknown -@end table - -Additionally, these filters support an @option{enable} command that can be used -to re-define the expression. - -Like any other filtering option, the @option{enable} option follows the same -rules. - -For example, to enable a blur filter (@ref{smartblur}) from 10 seconds to 3 -minutes, and a @ref{curves} filter starting at 3 seconds: -@example -smartblur = enable='between(t,10,3*60)', -curves = enable='gte(t,3)' : preset=cross_process -@end example - -@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. - -@emph{This filter is deprecated. Use @ref{aformat} instead.} - -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 adelay - -Delay one or more audio channels. - -Samples in delayed channel are filled with silence. - -The filter accepts the following option: - -@table @option -@item delays -Set list of delays in milliseconds for each channel separated by '|'. -At least one delay greater than 0 should be provided. -Unused delays will be silently ignored. If number of given delays is -smaller than number of channels all remaining channels will not be delayed. -@end table - -@subsection Examples - -@itemize -@item -Delay first channel by 1.5 seconds, the third channel by 0.5 seconds and leave -the second channel (and any other channels that may be present) unchanged. -@example -adelay=1500|0|500 -@end example -@end itemize - -@section aecho - -Apply echoing to the input audio. - -Echoes are reflected sound and can occur naturally amongst mountains -(and sometimes large buildings) when talking or shouting; digital echo -effects emulate this behaviour and are often used to help fill out the -sound of a single instrument or vocal. The time difference between the -original signal and the reflection is the @code{delay}, and the -loudness of the reflected signal is the @code{decay}. -Multiple echoes can have different delays and decays. - -A description of the accepted parameters follows. - -@table @option -@item in_gain -Set input gain of reflected signal. Default is @code{0.6}. - -@item out_gain -Set output gain of reflected signal. Default is @code{0.3}. - -@item delays -Set list of time intervals in milliseconds between original signal and reflections -separated by '|'. Allowed range for each @code{delay} is @code{(0 - 90000.0]}. -Default is @code{1000}. - -@item decays -Set list of loudnesses of reflected signals separated by '|'. -Allowed range for each @code{decay} is @code{(0 - 1.0]}. -Default is @code{0.5}. -@end table - -@subsection Examples - -@itemize -@item -Make it sound as if there are twice as many instruments as are actually playing: -@example -aecho=0.8:0.88:60:0.4 -@end example - -@item -If delay is very short, then it sound like a (metallic) robot playing music: -@example -aecho=0.8:0.88:6:0.4 -@end example - -@item -A longer delay will sound like an open air concert in the mountains: -@example -aecho=0.8:0.9:1000:0.3 -@end example - -@item -Same as above but with one more mountain: -@example -aecho=0.8:0.9:1000|1800:0.3|0.25 -@end example -@end itemize - -@section aeval - -Modify an audio signal according to the specified expressions. - -This filter accepts one or more expressions (one for each channel), -which are evaluated and used to modify a corresponding audio signal. - -This filter accepts the following options: - -@table @option -@item exprs -Set the '|'-separated expressions list for each separate channel. If -the number of input channels is greater than the number of -expressions, the last specified expression is used for the remaining -output channels. - -@item channel_layout, c -Set output channel layout. If not specified, the channel layout is -specified by the number of expressions. If set to @samp{same}, it will -use by default the same input channel layout. -@end table - -Each expression in @var{exprs} can contain the following constants and functions: - -@table @option -@item ch -channel number of the current expression - -@item n -number of the evaluated sample, starting from 0 - -@item s -sample rate - -@item t -time of the evaluated sample expressed in seconds - -@item nb_in_channels -@item nb_out_channels -input and output number of channels - -@item val(CH) -the value of input channel with number @var{CH} -@end table - -Note: this filter is slow. For faster processing you should use a -dedicated filter. - -@subsection Examples - -@itemize -@item -Half volume: -@example -aeval=val(ch)/2:c=same -@end example - -@item -Invert phase of the second channel: -@example -eval=val(0)|-val(1) -@end example -@end itemize - -@section afade - -Apply fade-in/out effect to input audio. - -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 for starting to apply the fade effect. Default is 0. -The accepted syntax is: -@example -[-]HH[:MM[:SS[.m...]]] -[-]S+[.m...] -@end example -See also the function @code{av_parse_time()}. -If set this option is used instead of @var{start_sample} one. - -@item duration, d -Specify the duration for which the fade effect has to last. Default is 0. -The accepted syntax is: -@example -[-]HH[:MM[:SS[.m...]]] -[-]S+[.m...] -@end example -See also the function @code{av_parse_time()}. -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. -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:st=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 '|'-separated list of requested sample formats. - -@item sample_rates -A '|'-separated list of requested sample rates. - -@item channel_layouts -A '|'-separated list of requested channel layouts. - -See @ref{channel layout syntax,,the Channel Layout section in the ffmpeg-utils(1) manual,ffmpeg-utils} -for the required syntax. -@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 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 the following options: - -@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 amerge - -Merge two or more audio streams into a single multi-channel stream. - -The filter accepts the following 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 assuming 1 video stream and 6 audio streams in @file{input.mkv}: -@example -ffmpeg -i input.mkv -filter_complex "[0:1][0:2][0:3][0:4][0:5][0:6] amerge=inputs=6" -c:a pcm_s16le output.mkv -@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. - -@section aphaser -Add a phasing effect to the input audio. - -A phaser filter creates series of peaks and troughs in the frequency spectrum. -The position of the peaks and troughs are modulated so that they vary over time, creating a sweeping effect. - -A description of the accepted parameters follows. - -@table @option -@item in_gain -Set input gain. Default is 0.4. - -@item out_gain -Set output gain. Default is 0.74 - -@item delay -Set delay in milliseconds. Default is 3.0. - -@item decay -Set decay. Default is 0.4. - -@item speed -Set modulation speed in Hz. Default is 0.5. - -@item type -Set modulation type. Default is triangular. - -It accepts the following values: -@table @samp -@item triangular, t -@item sinusoidal, s -@end table -@end table - -@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 the following options: - -@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 asetrate - -Set the sample rate without altering the PCM data. -This will result in a change of speed and pitch. - -The filter accepts the following options: - -@table @option -@item sample_rate, r -Set the output sample rate. Default is 44100 Hz. -@end table - -@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 astats - -Display time domain statistical information about the audio channels. -Statistics are calculated and displayed for each audio channel and, -where applicable, an overall figure is also given. - -The filter accepts the following option: -@table @option -@item length -Short window length in seconds, used for peak and trough RMS measurement. -Default is @code{0.05} (50 miliseconds). Allowed range is @code{[0.1 - 10]}. -@end table - -A description of each shown parameter follows: - -@table @option -@item DC offset -Mean amplitude displacement from zero. - -@item Min level -Minimal sample level. - -@item Max level -Maximal sample level. - -@item Peak level dB -@item RMS level dB -Standard peak and RMS level measured in dBFS. - -@item RMS peak dB -@item RMS trough dB -Peak and trough values for RMS level measured over a short window. - -@item Crest factor -Standard ratio of peak to RMS level (note: not in dB). - -@item Flat factor -Flatness (i.e. consecutive samples with the same value) of the signal at its peak levels -(i.e. either @var{Min level} or @var{Max level}). - -@item Peak count -Number of occasions (not the number of samples) that the signal attained either -@var{Min level} or @var{Max level}. -@end table - -@section astreamsync - -Forward two audio streams and control the order the buffers are forwarded. - -The filter accepts the following options: - -@table @option -@item expr, e -Set the 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. -@end table - -@subsection Examples - -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 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 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 atrim - -Trim the input so that the output contains one continuous subpart of the input. - -This filter accepts the following options: -@table @option -@item start -Specify time of the start of the kept section, i.e. the audio sample -with the timestamp @var{start} will be the first sample in the output. - -@item end -Specify time of the first audio sample that will be dropped, i.e. the -audio sample immediately preceding the one with the timestamp @var{end} will be -the last sample in the output. - -@item start_pts -Same as @var{start}, except this option sets the start timestamp in samples -instead of seconds. - -@item end_pts -Same as @var{end}, except this option sets the end timestamp in samples instead -of seconds. - -@item duration -Specify maximum duration of the output. - -@item start_sample -Number of the first sample that should be passed to output. - -@item end_sample -Number of the first sample that should be dropped. -@end table - -@option{start}, @option{end}, @option{duration} are expressed as time -duration specifications, check the "Time duration" section in the -ffmpeg-utils manual. - -Note that the first two sets of the start/end options and the @option{duration} -option look at the frame timestamp, while the _sample options simply count the -samples that pass through the filter. So start/end_pts and start/end_sample will -give different results when the timestamps are wrong, inexact or do not start at -zero. Also note that this filter does not modify the timestamps. If you wish -that the output timestamps start at zero, insert the asetpts filter after the -atrim filter. - -If multiple start or end options are set, this filter tries to be greedy and -keep all samples that match at least one of the specified constraints. To keep -only the part that matches all the constraints at once, chain multiple atrim -filters. - -The defaults are such that all the input is kept. So it is possible to set e.g. -just the end values to keep everything before the specified time. - -Examples: -@itemize -@item -drop everything except the second minute of input -@example -ffmpeg -i INPUT -af atrim=60:120 -@end example - -@item -keep only the first 1000 samples -@example -ffmpeg -i INPUT -af atrim=end_sample=1000 -@end example - -@end itemize - -@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 the following options: - -@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 the following options: - -@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 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 the following options: - -@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 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 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 '|'-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 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 compand - -Compress or expand audio dynamic range. - -A description of the accepted options follows. - -@table @option -@item attacks -@item decays -Set list of times in seconds for each channel over which the instantaneous -level of the input signal is averaged to determine its volume. -@option{attacks} refers to increase of volume and @option{decays} refers -to decrease of volume. -For most situations, the attack time (response to the audio getting louder) -should be shorter than the decay time because the human ear is more sensitive -to sudden loud audio than sudden soft audio. -Typical value for attack is @code{0.3} seconds and for decay @code{0.8} -seconds. - -@item points -Set list of points for transfer function, specified in dB relative to maximum -possible signal amplitude. -Each key points list need to be defined using the following syntax: -@code{x0/y0 x1/y1 x2/y2 ...}. - -The input values must be in strictly increasing order but the transfer -function does not have to be monotonically rising. -The point @code{0/0} is assumed but may be overridden (by @code{0/out-dBn}). -Typical values for the transfer function are @code{-70/-70 -60/-20}. - -@item soft-knee -Set amount for which the points at where adjacent line segments on the -transfer function meet will be rounded. Defaults is @code{0.01}. - -@item gain -Set additional gain in dB to be applied at all points on the transfer function -and allows easy adjustment of the overall gain. -Default is @code{0}. - -@item volume -Set initial volume in dB to be assumed for each channel when filtering starts. -This permits the user to supply a nominal level initially, so that, -for example, a very large gain is not applied to initial signal levels before -the companding has begun to operate. A typical value for audio which is -initially quiet is -90 dB. Default is @code{0}. - -@item delay -Set delay in seconds. Default is @code{0}. The input audio -is analysed immediately, but audio is delayed before being fed to the -volume adjuster. Specifying a delay approximately equal to the attack/decay -times allows the filter to effectively operate in predictive rather than -reactive mode. -@end table - -@subsection Examples -@itemize -@item -Make music with both quiet and loud passages suitable for listening -in a noisy environment: -@example -compand=.3 .3:1 1:-90/-60 -60/-40 -40/-30 -20/-20:6:0:-90:0.2 -@end example - -@item -Noise-gate for when the noise is at a lower level than the signal: -@example -compand=.1 .1:.2 .2:-900/-900 -50.1/-900 -50/-50:.01:0:-90:.1 -@end example - -@item -Here is another noise-gate, this time for when the noise is at a higher level -than the signal (making it, in some ways, similar to squelch): -@example -compand=.1 .1:.1 .1:-45.1/-45.1 -45/-900 0/-900:.01:45:-90:.1 -@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 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 the following options: - -@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 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 the following options: - -@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 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 '|'-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 ladspa - -Load a LADSPA (Linux Audio Developer's Simple Plugin API) plugin. - -To enable compilation of this filter you need to configure FFmpeg with -@code{--enable-ladspa}. - -@table @option -@item file, f -Specifies the name of LADSPA plugin library to load. If the environment -variable @env{LADSPA_PATH} is defined, the LADSPA plugin is searched in -each one of the directories specified by the colon separated list in -@env{LADSPA_PATH}, otherwise in the standard LADSPA paths, which are in -this order: @file{HOME/.ladspa/lib/}, @file{/usr/local/lib/ladspa/}, -@file{/usr/lib/ladspa/}. - -@item plugin, p -Specifies the plugin within the library. Some libraries contain only -one plugin, but others contain many of them. If this is not set filter -will list all available plugins within the specified library. - -@item controls, c -Set the '|' separated list of controls which are zero or more floating point -values that determine the behavior of the loaded plugin (for example delay, -threshold or gain). -Controls need to be defined using the following syntax: -c0=@var{value0}|c1=@var{value1}|c2=@var{value2}|..., where -@var{valuei} is the value set on the @var{i}-th control. -If @option{controls} is set to @code{help}, all available controls and -their valid ranges are printed. - -@item sample_rate, s -Specify the sample rate, default to 44100. Only used if plugin have -zero inputs. - -@item nb_samples, n -Set the number of samples per channel per each output frame, default -is 1024. Only used if plugin have zero inputs. - -@item duration, d -Set the minimum duration of the sourced audio. See the function -@code{av_parse_time()} for the accepted format, also check the "Time duration" -section in the ffmpeg-utils manual. -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. -Only used if plugin have zero inputs. - -@end table - -@subsection Examples - -@itemize -@item -List all available plugins within amp (LADSPA example plugin) library: -@example -ladspa=file=amp -@end example - -@item -List all available controls and their valid ranges for @code{vcf_notch} -plugin from @code{VCF} library: -@example -ladspa=f=vcf:p=vcf_notch:c=help -@end example - -@item -Simulate low quality audio equipment using @code{Computer Music Toolkit} (CMT) -plugin library: -@example -ladspa=file=cmt:plugin=lofi:controls=c0=22|c1=12|c2=12 -@end example - -@item -Add reverberation to the audio using TAP-plugins -(Tom's Audio Processing plugins): -@example -ladspa=file=tap_reverb:tap_reverb -@end example - -@item -Generate white noise, with 0.2 amplitude: -@example -ladspa=file=cmt:noise_source_white:c=c0=.2 -@end example - -@item -Generate 20 bpm clicks using plugin @code{C* Click - Metronome} from the -@code{C* Audio Plugin Suite} (CAPS) library: -@example -ladspa=file=caps:Click:c=c1=20' -@end example - -@item -Apply @code{C* Eq10X2 - Stereo 10-band equaliser} effect: -@example -ladspa=caps:Eq10X2:c=c0=-48|c9=-24|c3=12|c4=2 -@end example -@end itemize - -@subsection Commands - -This filter supports the following commands: -@table @option -@item cN -Modify the @var{N}-th control value. - -If the specified value is not valid, it is ignored and prior one is kept. -@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 the following options: - -@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 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 replaygain - -ReplayGain scanner filter. This filter takes an audio stream as an input and -outputs it unchanged. -At end of filtering it displays @code{track_gain} and @code{track_peak}. - -@section resample - -Convert the audio sample format, sample rate and channel layout. This filter is -not meant to be used directly. - -@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. - -The filter accepts the following options: - -@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 -i silence.mp3 -af silencedetect=noise=0.0001 -f null - -@end example -@end itemize - -@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 the following options: - -@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 volume - -Adjust the input audio volume. - -The filter accepts the following options: - -@table @option - -@item volume -Set audio volume expression. - -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 - -@item eval -Set when the volume expression is evaluated. - -It accepts the following values: -@table @samp -@item once -only evaluate expression once during the filter initialization, or -when the @samp{volume} command is sent - -@item frame -evaluate expression for each incoming frame -@end table - -Default value is @samp{once}. -@end table - -The volume expression can contain the following parameters. - -@table @option -@item n -frame number (starting at zero) -@item nb_channels -number of channels -@item nb_consumed_samples -number of samples consumed by the filter -@item nb_samples -number of samples in the current frame -@item pos -original frame position in the file -@item pts -frame PTS -@item sample_rate -sample rate -@item startpts -PTS at start of stream -@item startt -time at start of stream -@item t -frame time -@item tb -timestamp timebase -@item volume -last set volume value -@end table - -Note that when @option{eval} is set to @samp{once} only the -@var{sample_rate} and @var{tb} variables are available, all other -variables will evaluate to NAN. - -@subsection Commands - -This filter supports the following commands: -@table @option -@item volume -Modify the volume expression. -The command accepts the same syntax of the corresponding option. - -If the specified expression is not valid, it is kept at its current -value. -@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 - -@item -Fade volume after time 10 with an annihilation period of 5 seconds: -@example -volume='if(lt(t,10),1,max(1-(t-10)/5,0))':eval=frame -@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 a 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 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 -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=sample_rate=44100:sample_fmt=s16p:channel_layout=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=sample_rate=44100:sample_fmt=6:channel_layout=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. - -This source accepts the following options: - -@table @option -@item exprs -Set the '|'-separated expressions list for each separate channel. In case the -@option{channel_layout} option is not specified, the selected channel layout -depends on the number of provided expressions. Otherwise the last -specified expression is applied to the remaining output channels. - -@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). - -This source accepts the following options: - -@table @option - -@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 sample_rate, r -Specify the sample rate, and defaults to 44100. - -@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 - -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 filter accepts the following options: - -@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. - -The filter accepts the following options: - -@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, r -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} -or the options system. - -It accepts 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. - -@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. - -The filter accepts the following option: - -@table @option -@item min_val -Set the minimal luminance value. Default is @code{16}. -@end table - -@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. - -The filter accepts the following options: - -@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 the following options: - -@table @option - -@item amount -Set the percentage of the pixels that have to be below the threshold, defaults -to @code{98}. - -@item threshold, thresh -Set the threshold below which a pixel value is considered black, defaults to -@code{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. - -A description of the accepted options follows. - -@table @option -@item c0_mode -@item c1_mode -@item c2_mode -@item c3_mode -@item all_mode -Set blend mode for specific pixel component or all pixel components in case -of @var{all_mode}. Default value is @code{normal}. - -Available values for component modes are: -@table @samp -@item addition -@item and -@item average -@item burn -@item darken -@item difference -@item divide -@item dodge -@item exclusion -@item hardlight -@item lighten -@item multiply -@item negation -@item normal -@item or -@item overlay -@item phoenix -@item pinlight -@item reflect -@item screen -@item softlight -@item subtract -@item vividlight -@item xor -@end table - -@item c0_opacity -@item c1_opacity -@item c2_opacity -@item c3_opacity -@item all_opacity -Set blend opacity for specific pixel component or all pixel components in case -of @var{all_opacity}. Only used in combination with pixel component blend modes. - -@item c0_expr -@item c1_expr -@item c2_expr -@item c3_expr -@item all_expr -Set blend expression for specific pixel component or all pixel components in case -of @var{all_expr}. Note that related mode options will be ignored if those are set. - -The expressions can use the following variables: - -@table @option -@item N -The sequential number of the filtered frame, starting from @code{0}. - -@item X -@item Y -the coordinates of the current sample - -@item W -@item H -the width and height of currently filtered plane - -@item SW -@item SH -Width and height scale depending on the currently filtered plane. It is the -ratio between the corresponding luma plane number of pixels and the current -plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and -@code{0.5,0.5} for chroma planes. - -@item T -Time of the current frame, expressed in seconds. - -@item TOP, A -Value of pixel component at current location for first video frame (top layer). - -@item BOTTOM, B -Value of pixel component at current location for second video frame (bottom layer). -@end table - -@item shortest -Force termination when the shortest input terminates. Default is @code{0}. -@item repeatlast -Continue applying the last bottom frame after the end of the stream. A value of -@code{0} disable the filter after the last frame of the bottom layer is reached. -Default is @code{1}. -@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 - -@item -Apply uncover left effect: -@example -blend=all_expr='if(gte(N*SW+X,W),A,B)' -@end example - -@item -Apply uncover down effect: -@example -blend=all_expr='if(gte(Y-N*SH,0),A,B)' -@end example - -@item -Apply uncover up-left effect: -@example -blend=all_expr='if(gte(T*SH*40+Y,H)*gte((T*40*SW+X)*W/H,W),A,B)' -@end example -@end itemize - -@section boxblur - -Apply boxblur algorithm to the input video. - -The filter accepts the following options: - -@table @option - -@item luma_radius, lr -@item luma_power, lp -@item chroma_radius, cr -@item chroma_power, cp -@item alpha_radius, ar -@item alpha_power, ap - -@end table - -A description of the accepted options follows. - -@table @option -@item luma_radius, lr -@item chroma_radius, cr -@item alpha_radius, ar -Set an expression for the box radius in pixels used for blurring the -corresponding input plane. - -The radius value must be a non-negative number, and must not be -greater than the value of the expression @code{min(w,h)/2} for the -luma and alpha planes, and of @code{min(cw,ch)/2} for the chroma -planes. - -Default value for @option{luma_radius} is "2". If not specified, -@option{chroma_radius} and @option{alpha_radius} default to the -corresponding value set for @option{luma_radius}. - -The expressions can contain the following constants: -@table @option -@item w -@item h -the input width and height in pixels - -@item cw -@item ch -the input chroma image width and height in pixels - -@item hsub -@item vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. -@end table - -@item luma_power, lp -@item chroma_power, cp -@item alpha_power, ap -Specify how many times the boxblur filter is applied to the -corresponding plane. - -Default value for @option{luma_power} is 2. If not specified, -@option{chroma_power} and @option{alpha_power} default to the -corresponding value set for @option{luma_power}. - -A value of 0 will disable the effect. -@end table - -@subsection Examples - -@itemize -@item -Apply a boxblur filter with luma, chroma, and alpha radius -set to 2: -@example -boxblur=luma_radius=2:luma_power=1 -boxblur=2:1 -@end example - -@item -Set luma radius to 2, alpha and chroma radius to 0: -@example -boxblur=2:1:cr=0:ar=0 -@end example - -@item -Set luma and chroma radius to a fraction of the video dimension: -@example -boxblur=luma_radius=min(h\,w)/10:luma_power=1:chroma_radius=min(cw\,ch)/10:chroma_power=1 -@end example -@end itemize - -@section colorbalance -Modify intensity of primary colors (red, green and blue) of input frames. - -The filter allows an input frame to be adjusted in the shadows, midtones or highlights -regions for the red-cyan, green-magenta or blue-yellow balance. - -A positive adjustment value shifts the balance towards the primary color, a negative -value towards the complementary color. - -The filter accepts the following options: - -@table @option -@item rs -@item gs -@item bs -Adjust red, green and blue shadows (darkest pixels). - -@item rm -@item gm -@item bm -Adjust red, green and blue midtones (medium pixels). - -@item rh -@item gh -@item bh -Adjust red, green and blue highlights (brightest pixels). - -Allowed ranges for options are @code{[-1.0, 1.0]}. Defaults are @code{0}. -@end table - -@subsection Examples - -@itemize -@item -Add red color cast to shadows: -@example -colorbalance=rs=.3 -@end example -@end itemize - -@section colorchannelmixer - -Adjust video input frames by re-mixing color channels. - -This filter modifies a color channel by adding the values associated to -the other channels of the same pixels. For example if the value to -modify is red, the output value will be: -@example -@var{red}=@var{red}*@var{rr} + @var{blue}*@var{rb} + @var{green}*@var{rg} + @var{alpha}*@var{ra} -@end example - -The filter accepts the following options: - -@table @option -@item rr -@item rg -@item rb -@item ra -Adjust contribution of input red, green, blue and alpha channels for output red channel. -Default is @code{1} for @var{rr}, and @code{0} for @var{rg}, @var{rb} and @var{ra}. - -@item gr -@item gg -@item gb -@item ga -Adjust contribution of input red, green, blue and alpha channels for output green channel. -Default is @code{1} for @var{gg}, and @code{0} for @var{gr}, @var{gb} and @var{ga}. - -@item br -@item bg -@item bb -@item ba -Adjust contribution of input red, green, blue and alpha channels for output blue channel. -Default is @code{1} for @var{bb}, and @code{0} for @var{br}, @var{bg} and @var{ba}. - -@item ar -@item ag -@item ab -@item aa -Adjust contribution of input red, green, blue and alpha channels for output alpha channel. -Default is @code{1} for @var{aa}, and @code{0} for @var{ar}, @var{ag} and @var{ab}. - -Allowed ranges for options are @code{[-2.0, 2.0]}. -@end table - -@subsection Examples - -@itemize -@item -Convert source to grayscale: -@example -colorchannelmixer=.3:.4:.3:0:.3:.4:.3:0:.3:.4:.3 -@end example -@item -Simulate sepia tones: -@example -colorchannelmixer=.393:.769:.189:0:.349:.686:.168:0:.272:.534:.131 -@end example -@end itemize - -@section colormatrix - -Convert color matrix. - -The filter accepts the following options: - -@table @option -@item src -@item dst -Specify the source and destination color matrix. Both values must be -specified. - -The accepted values are: -@table @samp -@item bt709 -BT.709 - -@item bt601 -BT.601 - -@item smpte240m -SMPTE-240M - -@item fcc -FCC -@end table -@end table - -For example to convert from BT.601 to SMPTE-240M, use the command: -@example -colormatrix=bt601:smpte240m -@end example - -@section copy - -Copy the input source unchanged to the output. Mainly useful for -testing purposes. - -@section crop - -Crop the input video to given dimensions. - -The filter accepts the following options: - -@table @option -@item w, out_w -Width of the output video. It defaults to @code{iw}. -This expression is evaluated only once during the filter -configuration. - -@item h, out_h -Height of the output video. It defaults to @code{ih}. -This expression is evaluated only once during the filter -configuration. - -@item x -Horizontal position, in the input video, of the left edge of the output video. -It defaults to @code{(in_w-out_w)/2}. -This expression is evaluated per-frame. - -@item y -Vertical position, in the input video, of the top edge of the output video. -It defaults to @code{(in_h-out_h)/2}. -This expression is evaluated per-frame. - -@item keep_aspect -If set to 1 will force the output display aspect ratio -to be the same of the input, by changing the output sample aspect -ratio. It defaults to 0. -@end table - -The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are -expressions containing the following constants: - -@table @option -@item x -@item y -the computed values for @var{x} and @var{y}. They are evaluated for -each new frame. - -@item in_w -@item in_h -the input width and height - -@item iw -@item ih -same as @var{in_w} and @var{in_h} - -@item out_w -@item out_h -the output (cropped) width and height - -@item ow -@item 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 -@item 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 pos -the position in the file of the input frame, NAN if unknown - -@item t -timestamp expressed in seconds, NAN if the input timestamp is unknown - -@end table - -The expression for @var{out_w} may depend on the value of @var{out_h}, -and the expression for @var{out_h} may depend on @var{out_w}, but they -cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are -evaluated after @var{out_w} and @var{out_h}. - -The @var{x} and @var{y} parameters specify the expressions for the -position of the top-left corner of the output (non-cropped) area. They -are evaluated for each frame. If the evaluated value is not valid, it -is approximated to the nearest valid value. - -The expression for @var{x} may depend on @var{y}, and the expression -for @var{y} may depend on @var{x}. - -@subsection Examples - -@itemize -@item -Crop area with size 100x100 at position (12,34). -@example -crop=100:100:12:34 -@end example - -Using named options, the example above becomes: -@example -crop=w=100:h=100:x=12:y=34 -@end example - -@item -Crop the central input area with size 100x100: -@example -crop=100:100 -@end example - -@item -Crop the central input area with size 2/3 of the input video: -@example -crop=2/3*in_w:2/3*in_h -@end example - -@item -Crop the input video central square: -@example -crop=out_w=in_h -crop=in_h -@end example - -@item -Delimit the rectangle with the top-left corner placed at position -100:100 and the right-bottom corner corresponding to the right-bottom -corner of the input image: -@example -crop=in_w-100:in_h-100:100:100 -@end example - -@item -Crop 10 pixels from the left and right borders, and 20 pixels from -the top and bottom borders -@example -crop=in_w-2*10:in_h-2*20 -@end example - -@item -Keep only the bottom right quarter of the input image: -@example -crop=in_w/2:in_h/2:in_w/2:in_h/2 -@end example - -@item -Crop height for getting Greek harmony: -@example -crop=in_w:1/PHI*in_w -@end example - -@item -Appply trembling effect: -@example -crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7) -@end example - -@item -Apply erratic camera effect depending on timestamp: -@example -crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)" -@end example - -@item -Set x depending on the value of y: -@example -crop=in_w/2:in_h/2:y:10+10*sin(n/10) -@end example -@end itemize - -@section cropdetect - -Auto-detect crop size. - -Calculate necessary cropping parameters and prints the recommended -parameters through the logging system. The detected dimensions -correspond to the non-black area of the input video. - -The filter accepts the following options: - -@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_count, 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 - -@anchor{curves} -@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 the following options: - -@table @option -@item preset -Select one of the available color presets. This option can be used in addition -to the @option{r}, @option{g}, @option{b} parameters; in this case, the later -options takes priority on the preset values. -Available presets are: -@table @samp -@item none -@item color_negative -@item cross_process -@item darker -@item increase_contrast -@item lighter -@item linear_contrast -@item medium_contrast -@item negative -@item strong_contrast -@item vintage -@end table -Default is @code{none}. -@item master, m -Set the master key points. These points will define a second pass mapping. It -is sometimes called a "luminance" or "value" mapping. It can be used with -@option{r}, @option{g}, @option{b} or @option{all} since it acts like a -post-processing LUT. -@item red, r -Set the key points for the red component. -@item green, g -Set the key points for the green component. -@item blue, b -Set the key points for the blue component. -@item all -Set the key points for all components (not including master). -Can be used in addition to the other key points component -options. In this case, the unset component(s) will fallback on this -@option{all} setting. -@item psfile -Specify a Photoshop curves file (@code{.asv}) to import the settings from. -@end table - -To avoid some filtergraph syntax conflicts, each key points list need to be -defined using the following syntax: @code{x0/y0 x1/y1 x2/y2 ...}. - -@subsection Examples - -@itemize -@item -Increase slightly the middle level of blue: -@example -curves=blue='0.5/0.58' -@end example - -@item -Vintage effect: -@example -curves=r='0/0.11 .42/.51 1/0.95':g='0.50/0.48':b='0/0.22 .49/.44 1/0.8' -@end example -Here we obtain the following coordinates for each components: -@table @var -@item red -@code{(0;0.11) (0.42;0.51) (1;0.95)} -@item green -@code{(0;0) (0.50;0.48) (1;1)} -@item blue -@code{(0;0.22) (0.49;0.44) (1;0.80)} -@end table - -@item -The previous example can also be achieved with the associated built-in preset: -@example -curves=preset=vintage -@end example - -@item -Or simply: -@example -curves=vintage -@end example - -@item -Use a Photoshop preset and redefine the points of the green component: -@example -curves=psfile='MyCurvesPresets/purple.asv':green='0.45/0.53' -@end example -@end itemize - -@section dctdnoiz - -Denoise frames using 2D DCT (frequency domain filtering). - -This filter is not designed for real time and can be extremely slow. - -The filter accepts the following options: - -@table @option -@item sigma, s -Set the noise sigma constant. - -This @var{sigma} defines a hard threshold of @code{3 * sigma}; every DCT -coefficient (absolute value) below this threshold with be dropped. - -If you need a more advanced filtering, see @option{expr}. - -Default is @code{0}. - -@item overlap -Set number overlapping pixels for each block. Each block is of size -@code{16x16}. Since the filter can be slow, you may want to reduce this value, -at the cost of a less effective filter and the risk of various artefacts. - -If the overlapping value doesn't allow to process the whole input width or -height, a warning will be displayed and according borders won't be denoised. - -Default value is @code{15}. - -@item expr, e -Set the coefficient factor expression. - -For each coefficient of a DCT block, this expression will be evaluated as a -multiplier value for the coefficient. - -If this is option is set, the @option{sigma} option will be ignored. - -The absolute value of the coefficient can be accessed through the @var{c} -variable. -@end table - -@subsection Examples - -Apply a denoise with a @option{sigma} of @code{4.5}: -@example -dctdnoiz=4.5 -@end example - -The same operation can be achieved using the expression system: -@example -dctdnoiz=e='gte(c, 4.5*3)' -@end example - -@anchor{decimate} -@section decimate - -Drop duplicated frames at regular intervals. - -The filter accepts the following options: - -@table @option -@item cycle -Set the number of frames from which one will be dropped. Setting this to -@var{N} means one frame in every batch of @var{N} frames will be dropped. -Default is @code{5}. - -@item dupthresh -Set the threshold for duplicate detection. If the difference metric for a frame -is less than or equal to this value, then it is declared as duplicate. Default -is @code{1.1} - -@item scthresh -Set scene change threshold. Default is @code{15}. - -@item blockx -@item blocky -Set the size of the x and y-axis blocks used during metric calculations. -Larger blocks give better noise suppression, but also give worse detection of -small movements. Must be a power of two. Default is @code{32}. - -@item ppsrc -Mark main input as a pre-processed input and activate clean source input -stream. This allows the input to be pre-processed with various filters to help -the metrics calculation while keeping the frame selection lossless. When set to -@code{1}, the first stream is for the pre-processed input, and the second -stream is the clean source from where the kept frames are chosen. Default is -@code{0}. - -@item chroma -Set whether or not chroma is considered in the metric calculations. Default is -@code{1}. -@end table - -@section delogo - -Suppress a TV station logo by a simple interpolation of the surrounding -pixels. Just set a rectangle covering the logo and watch it disappear -(and sometimes something even uglier appear - your mileage may vary). - -This filter accepts the following options: -@table @option - -@item x -@item y -Specify the top left corner coordinates of the logo. They must be -specified. - -@item w -@item 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}, and @var{h} parameters. -The default value is 0. - -The rectangle is drawn on the outermost pixels which will be (partly) -replaced with interpolated values. The values of the next pixels -immediately outside this rectangle in each direction will be used to -compute the interpolated pixel values inside the rectangle. - -@end table - -@subsection Examples - -@itemize -@item -Set a rectangle covering the area with top left corner coordinates 0,0 -and size 100x77, setting a band of size 10: -@example -delogo=x=0:y=0:w=100:h=77:band=10 -@end example - -@end itemize - -@section deshake - -Attempt to fix small changes in horizontal and/or vertical shift. This -filter helps remove camera shake from hand-holding a camera, bumping a -tripod, moving on a vehicle, etc. - -The filter accepts the following options: - -@table @option - -@item x -@item y -@item w -@item 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 -@item ry -Specify the maximum extent of movement in x and y directions in the -range 0-64 pixels. Default 16. - -@item edge -Specify how to generate pixels to fill blanks at the edge of the -frame. Available values are: -@table @samp -@item blank, 0 -Fill zeroes at blank locations -@item original, 1 -Original image at blank locations -@item clamp, 2 -Extruded edge value at blank locations -@item mirror, 3 -Mirrored edge at blank locations -@end table -Default value is @samp{mirror}. - -@item blocksize -Specify the blocksize to use for motion search. Range 4-128 pixels, -default 8. - -@item contrast -Specify the contrast threshold for blocks. Only blocks with more than -the specified contrast (difference between darkest and lightest -pixels) will be considered. Range 1-255, default 125. - -@item search -Specify the search strategy. Available values are: -@table @samp -@item exhaustive, 0 -Set exhaustive search -@item less, 1 -Set less exhaustive search. -@end table -Default value is @samp{exhaustive}. - -@item filename -If set then a detailed log of the motion search is written to the -specified file. - -@item opencl -If set to 1, specify using OpenCL capabilities, only available if -FFmpeg was configured with @code{--enable-opencl}. Default value is 0. - -@end table - -@section drawbox - -Draw a colored box on the input image. - -This filter accepts the following options: - -@table @option -@item x -@item y -The expressions which specify the top left corner coordinates of the box. Default to 0. - -@item width, w -@item height, h -The expressions which 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. For the general syntax of this option, -check the "Color" section in the ffmpeg-utils manual. If the special -value @code{invert} is used, the box edge color is the same as the -video with inverted luma. - -@item thickness, t -The expression which sets the thickness of the box edge. Default value is @code{3}. - -See below for the list of accepted constants. -@end table - -The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the -following constants: - -@table @option -@item dar -The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}. - -@item hsub -@item vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. - -@item in_h, ih -@item in_w, iw -The input width and height. - -@item sar -The input sample aspect ratio. - -@item x -@item y -The x and y offset coordinates where the box is drawn. - -@item w -@item h -The width and height of the drawn box. - -@item t -The thickness of the drawn box. - -These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to -each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}. - -@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 - -@item -Draw a 2-pixel red 2.40:1 mask: -@example -drawbox=x=-t:y=0.5*(ih-iw/2.4)-t:w=iw+t*2:h=iw/2.4+t*2:t=2:c=red -@end example -@end itemize - -@section drawgrid - -Draw a grid on the input image. - -This filter accepts the following options: - -@table @option -@item x -@item y -The expressions which specify the coordinates of some point of grid intersection (meant to configure offset). Both default to 0. - -@item width, w -@item height, h -The expressions which specify the width and height of the grid cell, if 0 they are interpreted as the -input width and height, respectively, minus @code{thickness}, so image gets -framed. Default to 0. - -@item color, c -Specify the color of the grid. For the general syntax of this option, -check the "Color" section in the ffmpeg-utils manual. If the special -value @code{invert} is used, the grid color is the same as the -video with inverted luma. - -@item thickness, t -The expression which sets the thickness of the grid line. Default value is @code{1}. - -See below for the list of accepted constants. -@end table - -The parameters for @var{x}, @var{y}, @var{w} and @var{h} and @var{t} are expressions containing the -following constants: - -@table @option -@item dar -The input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}. - -@item hsub -@item vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. - -@item in_h, ih -@item in_w, iw -The input grid cell width and height. - -@item sar -The input sample aspect ratio. - -@item x -@item y -The x and y coordinates of some point of grid intersection (meant to configure offset). - -@item w -@item h -The width and height of the drawn cell. - -@item t -The thickness of the drawn cell. - -These constants allow the @var{x}, @var{y}, @var{w}, @var{h} and @var{t} expressions to refer to -each other, so you may for example specify @code{y=x/dar} or @code{h=w/dar}. - -@end table - -@subsection Examples - -@itemize -@item -Draw a grid with cell 100x100 pixels, thickness 2 pixels, with color red and an opacity of 50%: -@example -drawgrid=width=100:height=100:thickness=2:color=red@@0.5 -@end example - -@item -Draw a white 3x3 grid with an opacity of 50%: -@example -drawgrid=w=iw/3:h=ih/3:t=2:c=white@@0.5 -@end example -@end itemize - -@anchor{drawtext} -@section drawtext - -Draw text string or text from specified file on top of video using the -libfreetype library. - -To enable compilation of this filter you need to configure FFmpeg with -@code{--enable-libfreetype}. - -@subsection Syntax - -The description of the accepted parameters follows. - -@table @option - -@item box -Used to draw a box around text using background color. -Value should be either 1 (enable) or 0 (disable). -The default value of @var{box} is 0. - -@item boxcolor -The color to be used for drawing box around text. For the syntax of this -option, check the "Color" section in the ffmpeg-utils manual. - -The default value of @var{boxcolor} is "white". - -@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. For the syntax of this option, check -the "Color" section in the ffmpeg-utils manual. - -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 -@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. For the -syntax of this option, check the "Color" section in the ffmpeg-utils manual. - -The default value of @var{shadowcolor} is "black". - -@item shadowx -@item 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 start_number -The starting frame number for the n/frame_num variable. The default value -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 -@item 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 -@item 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 -@item y -the x and y offset coordinates where the text is drawn. - -These parameters allow the @var{x} and @var{y} expressions to refer -each other, so you can for example specify @code{y=x/dar}. -@end table - -If libavfilter was built with @code{--enable-fontconfig}, then -@option{fontfile} can be a fontconfig pattern or omitted. - -@anchor{drawtext_expansion} -@subsection Text expansion - -If @option{expansion} is set to @code{strftime}, -the filter recognizes strftime() sequences in the provided text and -expands them accordingly. Check the documentation of strftime(). This -feature is deprecated. - -If @option{expansion} is set to @code{none}, the text is printed verbatim. - -If @option{expansion} is set to @code{normal} (which is the default), -the following expansion mechanism is used. - -The backslash character '\', followed by any character, always expands to -the second character. - -Sequence of the form @code{%@{...@}} are expanded. The text between the -braces is a function name, possibly followed by arguments separated by ':'. -If the arguments contain special characters or delimiters (':' or '@}'), -they should be escaped. - -Note that they probably must also be escaped as the value for the -@option{text} option in the filter argument string and as the filter -argument in the filtergraph description, and possibly also for the shell, -that makes up to four levels of escaping; using a text file avoids these -problems. - -The following functions are available: - -@table @command - -@item expr, e -The expression evaluation result. - -It must take one argument specifying the expression to be evaluated, -which accepts the same constants and functions as the @var{x} and -@var{y} values. Note that not all constants should be used, for -example the text size is not known when evaluating the expression, so -the constants @var{text_w} and @var{text_h} will have an undefined -value. - -@item gmtime -The time at which the filter is running, expressed in UTC. -It can accept an argument: a strftime() format string. - -@item localtime -The time at which the filter is running, expressed in the local time zone. -It can accept an argument: a strftime() format string. - -@item metadata -Frame metadata. It must take one argument specifying metadata key. - -@item n, frame_num -The frame number, starting from 0. - -@item pict_type -A 1 character description of the current picture type. - -@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:enable=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. - -The filter accepts the following options: - -@table @option -@item low -@item 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 extractplanes - -Extract color channel components from input video stream into -separate grayscale video streams. - -The filter accepts the following option: - -@table @option -@item planes -Set plane(s) to extract. - -Available values for planes are: -@table @samp -@item y -@item u -@item v -@item a -@item r -@item g -@item b -@end table - -Choosing planes not available in the input will result in an error. -That means you cannot select @code{r}, @code{g}, @code{b} planes -with @code{y}, @code{u}, @code{v} planes at same time. -@end table - -@subsection Examples - -@itemize -@item -Extract luma, u and v color channel component from input video frame -into 3 grayscale outputs: -@example -ffmpeg -i video.avi -filter_complex 'extractplanes=y+u+v[y][u][v]' -map '[y]' y.avi -map '[u]' u.avi -map '[v]' v.avi -@end example -@end itemize - -@section elbg - -Apply a posterize effect using the ELBG (Enhanced LBG) algorithm. - -For each input image, the filter will compute the optimal mapping from -the input to the output given the codebook length, that is the number -of distinct output colors. - -This filter accepts the following options. - -@table @option -@item codebook_length, l -Set codebook length. The value must be a positive integer, and -represents the number of distinct output colors. Default value is 256. - -@item nb_steps, n -Set the maximum number of iterations to apply for computing the optimal -mapping. The higher the value the better the result and the higher the -computation time. Default value is 1. - -@item seed, s -Set a random seed, 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. -@end table - -@section fade - -Apply fade-in/out effect to input video. - -This filter accepts the following options: - -@table @option -@item type, t -The effect type -- can be either "in" for fade-in, or "out" for a fade-out -effect. -Default is @code{in}. - -@item start_frame, s -Specify the number of the start frame for starting to apply the fade -effect. Default is 0. - -@item nb_frames, n -The number of frames for which the fade effect has to last. At the end of the -fade-in effect the output video will have the same intensity as the input video, -at the end of the fade-out transition the output video will be filled with the -selected @option{color}. -Default is 25. - -@item alpha -If set to 1, fade only alpha channel, if one exists on the input. -Default value is 0. - -@item start_time, st -Specify the timestamp (in seconds) of the frame to start to apply the fade -effect. If both start_frame and start_time are specified, the fade will start at -whichever comes last. Default is 0. - -@item duration, d -The number of seconds 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 filled with the -selected @option{color}. -If both duration and nb_frames are specified, duration is used. Default is 0. - -@item color, c -Specify the color of the fade. Default is "black". -@end table - -@subsection Examples - -@itemize -@item -Fade in first 30 frames of video: -@example -fade=in:0:30 -@end example - -The command above is equivalent to: -@example -fade=t=in:s=0:n=30 -@end example - -@item -Fade out last 45 frames of a 200-frame video: -@example -fade=out:155:45 -fade=type=out:start_frame=155:nb_frames=45 -@end example - -@item -Fade in first 25 frames and fade out last 25 frames of a 1000-frame video: -@example -fade=in:0:25, fade=out:975:25 -@end example - -@item -Make first 5 frames yellow, then fade in from frame 5-24: -@example -fade=in:5:20:color=yellow -@end example - -@item -Fade in alpha over first 25 frames of video: -@example -fade=in:0:25:alpha=1 -@end example - -@item -Make first 5.5 seconds black, then fade in for 0.5 seconds: -@example -fade=t=in:st=5.5:d=0.5 -@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. - -The filter accepts the following 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 - -@section fieldmatch - -Field matching filter for inverse telecine. It is meant to reconstruct the -progressive frames from a telecined stream. The filter does not drop duplicated -frames, so to achieve a complete inverse telecine @code{fieldmatch} needs to be -followed by a decimation filter such as @ref{decimate} in the filtergraph. - -The separation of the field matching and the decimation is notably motivated by -the possibility of inserting a de-interlacing filter fallback between the two. -If the source has mixed telecined and real interlaced content, -@code{fieldmatch} will not be able to match fields for the interlaced parts. -But these remaining combed frames will be marked as interlaced, and thus can be -de-interlaced by a later filter such as @ref{yadif} before decimation. - -In addition to the various configuration options, @code{fieldmatch} can take an -optional second stream, activated through the @option{ppsrc} option. If -enabled, the frames reconstruction will be based on the fields and frames from -this second stream. This allows the first input to be pre-processed in order to -help the various algorithms of the filter, while keeping the output lossless -(assuming the fields are matched properly). Typically, a field-aware denoiser, -or brightness/contrast adjustments can help. - -Note that this filter uses the same algorithms as TIVTC/TFM (AviSynth project) -and VIVTC/VFM (VapourSynth project). The later is a light clone of TFM from -which @code{fieldmatch} is based on. While the semantic and usage are very -close, some behaviour and options names can differ. - -The filter accepts the following options: - -@table @option -@item order -Specify the assumed field order of the input stream. Available values are: - -@table @samp -@item auto -Auto detect parity (use FFmpeg's internal parity value). -@item bff -Assume bottom field first. -@item tff -Assume top field first. -@end table - -Note that it is sometimes recommended not to trust the parity announced by the -stream. - -Default value is @var{auto}. - -@item mode -Set the matching mode or strategy to use. @option{pc} mode is the safest in the -sense that it won't risk creating jerkiness due to duplicate frames when -possible, but if there are bad edits or blended fields it will end up -outputting combed frames when a good match might actually exist. On the other -hand, @option{pcn_ub} mode is the most risky in terms of creating jerkiness, -but will almost always find a good frame if there is one. The other values are -all somewhere in between @option{pc} and @option{pcn_ub} in terms of risking -jerkiness and creating duplicate frames versus finding good matches in sections -with bad edits, orphaned fields, blended fields, etc. - -More details about p/c/n/u/b are available in @ref{p/c/n/u/b meaning} section. - -Available values are: - -@table @samp -@item pc -2-way matching (p/c) -@item pc_n -2-way matching, and trying 3rd match if still combed (p/c + n) -@item pc_u -2-way matching, and trying 3rd match (same order) if still combed (p/c + u) -@item pc_n_ub -2-way matching, trying 3rd match if still combed, and trying 4th/5th matches if -still combed (p/c + n + u/b) -@item pcn -3-way matching (p/c/n) -@item pcn_ub -3-way matching, and trying 4th/5th matches if all 3 of the original matches are -detected as combed (p/c/n + u/b) -@end table - -The parenthesis at the end indicate the matches that would be used for that -mode assuming @option{order}=@var{tff} (and @option{field} on @var{auto} or -@var{top}). - -In terms of speed @option{pc} mode is by far the fastest and @option{pcn_ub} is -the slowest. - -Default value is @var{pc_n}. - -@item ppsrc -Mark the main input stream as a pre-processed input, and enable the secondary -input stream as the clean source to pick the fields from. See the filter -introduction for more details. It is similar to the @option{clip2} feature from -VFM/TFM. - -Default value is @code{0} (disabled). - -@item field -Set the field to match from. It is recommended to set this to the same value as -@option{order} unless you experience matching failures with that setting. In -certain circumstances changing the field that is used to match from can have a -large impact on matching performance. Available values are: - -@table @samp -@item auto -Automatic (same value as @option{order}). -@item bottom -Match from the bottom field. -@item top -Match from the top field. -@end table - -Default value is @var{auto}. - -@item mchroma -Set whether or not chroma is included during the match comparisons. In most -cases it is recommended to leave this enabled. You should set this to @code{0} -only if your clip has bad chroma problems such as heavy rainbowing or other -artifacts. Setting this to @code{0} could also be used to speed things up at -the cost of some accuracy. - -Default value is @code{1}. - -@item y0 -@item y1 -These define an exclusion band which excludes the lines between @option{y0} and -@option{y1} from being included in the field matching decision. An exclusion -band can be used to ignore subtitles, a logo, or other things that may -interfere with the matching. @option{y0} sets the starting scan line and -@option{y1} sets the ending line; all lines in between @option{y0} and -@option{y1} (including @option{y0} and @option{y1}) will be ignored. Setting -@option{y0} and @option{y1} to the same value will disable the feature. -@option{y0} and @option{y1} defaults to @code{0}. - -@item scthresh -Set the scene change detection threshold as a percentage of maximum change on -the luma plane. Good values are in the @code{[8.0, 14.0]} range. Scene change -detection is only relevant in case @option{combmatch}=@var{sc}. The range for -@option{scthresh} is @code{[0.0, 100.0]}. - -Default value is @code{12.0}. - -@item combmatch -When @option{combatch} is not @var{none}, @code{fieldmatch} will take into -account the combed scores of matches when deciding what match to use as the -final match. Available values are: - -@table @samp -@item none -No final matching based on combed scores. -@item sc -Combed scores are only used when a scene change is detected. -@item full -Use combed scores all the time. -@end table - -Default is @var{sc}. - -@item combdbg -Force @code{fieldmatch} to calculate the combed metrics for certain matches and -print them. This setting is known as @option{micout} in TFM/VFM vocabulary. -Available values are: - -@table @samp -@item none -No forced calculation. -@item pcn -Force p/c/n calculations. -@item pcnub -Force p/c/n/u/b calculations. -@end table - -Default value is @var{none}. - -@item cthresh -This is the area combing threshold used for combed frame detection. This -essentially controls how "strong" or "visible" combing must be to be detected. -Larger values mean combing must be more visible and smaller values mean combing -can be less visible or strong and still be detected. Valid settings are from -@code{-1} (every pixel will be detected as combed) to @code{255} (no pixel will -be detected as combed). This is basically a pixel difference value. A good -range is @code{[8, 12]}. - -Default value is @code{9}. - -@item chroma -Sets whether or not chroma is considered in the combed frame decision. Only -disable this if your source has chroma problems (rainbowing, etc.) that are -causing problems for the combed frame detection with chroma enabled. Actually, -using @option{chroma}=@var{0} is usually more reliable, except for the case -where there is chroma only combing in the source. - -Default value is @code{0}. - -@item blockx -@item blocky -Respectively set the x-axis and y-axis size of the window used during combed -frame detection. This has to do with the size of the area in which -@option{combpel} pixels are required to be detected as combed for a frame to be -declared combed. See the @option{combpel} parameter description for more info. -Possible values are any number that is a power of 2 starting at 4 and going up -to 512. - -Default value is @code{16}. - -@item combpel -The number of combed pixels inside any of the @option{blocky} by -@option{blockx} size blocks on the frame for the frame to be detected as -combed. While @option{cthresh} controls how "visible" the combing must be, this -setting controls "how much" combing there must be in any localized area (a -window defined by the @option{blockx} and @option{blocky} settings) on the -frame. Minimum value is @code{0} and maximum is @code{blocky x blockx} (at -which point no frames will ever be detected as combed). This setting is known -as @option{MI} in TFM/VFM vocabulary. - -Default value is @code{80}. -@end table - -@anchor{p/c/n/u/b meaning} -@subsection p/c/n/u/b meaning - -@subsubsection p/c/n - -We assume the following telecined stream: - -@example -Top fields: 1 2 2 3 4 -Bottom fields: 1 2 3 4 4 -@end example - -The numbers correspond to the progressive frame the fields relate to. Here, the -first two frames are progressive, the 3rd and 4th are combed, and so on. - -When @code{fieldmatch} is configured to run a matching from bottom -(@option{field}=@var{bottom}) this is how this input stream get transformed: - -@example -Input stream: - T 1 2 2 3 4 - B 1 2 3 4 4 <-- matching reference - -Matches: c c n n c - -Output stream: - T 1 2 3 4 4 - B 1 2 3 4 4 -@end example - -As a result of the field matching, we can see that some frames get duplicated. -To perform a complete inverse telecine, you need to rely on a decimation filter -after this operation. See for instance the @ref{decimate} filter. - -The same operation now matching from top fields (@option{field}=@var{top}) -looks like this: - -@example -Input stream: - T 1 2 2 3 4 <-- matching reference - B 1 2 3 4 4 - -Matches: c c p p c - -Output stream: - T 1 2 2 3 4 - B 1 2 2 3 4 -@end example - -In these examples, we can see what @var{p}, @var{c} and @var{n} mean; -basically, they refer to the frame and field of the opposite parity: - -@itemize -@item @var{p} matches the field of the opposite parity in the previous frame -@item @var{c} matches the field of the opposite parity in the current frame -@item @var{n} matches the field of the opposite parity in the next frame -@end itemize - -@subsubsection u/b - -The @var{u} and @var{b} matching are a bit special in the sense that they match -from the opposite parity flag. In the following examples, we assume that we are -currently matching the 2nd frame (Top:2, bottom:2). According to the match, a -'x' is placed above and below each matched fields. - -With bottom matching (@option{field}=@var{bottom}): -@example -Match: c p n b u - - x x x x x - Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2 - Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 - x x x x x - -Output frames: - 2 1 2 2 2 - 2 2 2 1 3 -@end example - -With top matching (@option{field}=@var{top}): -@example -Match: c p n b u - - x x x x x - Top 1 2 2 1 2 2 1 2 2 1 2 2 1 2 2 - Bottom 1 2 3 1 2 3 1 2 3 1 2 3 1 2 3 - x x x x x - -Output frames: - 2 2 2 1 2 - 2 1 3 2 2 -@end example - -@subsection Examples - -Simple IVTC of a top field first telecined stream: -@example -fieldmatch=order=tff:combmatch=none, decimate -@end example - -Advanced IVTC, with fallback on @ref{yadif} for still combed frames: -@example -fieldmatch=order=tff:combmatch=full, yadif=deint=interlaced, decimate -@end example - -@section fieldorder - -Transform the field order of the input video. - -This filter accepts the following options: - -@table @option - -@item order -Output field order. Valid values are @var{tff} for top field first or @var{bff} -for bottom field first. -@end table - -Default value is @samp{tff}. - -Transformation is achieved by shifting the picture content up or down -by one line, and filling the remaining line with appropriate picture content. -This method is consistent with most broadcast field order converters. - -If the input video is not flagged as being interlaced, or it is already -flagged as being of the required output field order then this filter does -not alter the incoming video. - -This filter is very useful when converting to or from PAL DV material, -which is bottom field first. - -For example: -@example -ffmpeg -i in.vob -vf "fieldorder=bff" out.dv -@end example - -@section fifo - -Buffer input images and send them when they are requested. - -This filter is mainly useful when auto-inserted by the libavfilter -framework. - -The filter does not take parameters. - -@anchor{format} -@section format - -Convert the input video to one of the specified pixel formats. -Libavfilter will try to pick one that is supported for the input to -the next filter. - -This filter accepts the following parameters: -@table @option - -@item pix_fmts -A '|'-separated list of pixel format names, for example -"pix_fmts=yuv420p|monow|rgb24". - -@end table - -@subsection Examples - -@itemize -@item -Convert the input video to the format @var{yuv420p} -@example -format=pix_fmts=yuv420p -@end example - -Convert the input video to any of the formats in the list -@example -format=pix_fmts=yuv420p|yuv444p|yuv410p -@end example -@end itemize - -@anchor{fps} -@section fps - -Convert the video to specified constant frame rate by duplicating or dropping -frames as necessary. - -This filter accepts the following named parameters: -@table @option - -@item fps -Desired output frame rate. The default is @code{25}. - -@item round -Rounding method. - -Possible values are: -@table @option -@item zero -zero round towards 0 -@item inf -round away from 0 -@item down -round towards -infinity -@item up -round towards +infinity -@item near -round to nearest -@end table -The default is @code{near}. - -@item start_time -Assume the first PTS should be the given value, in seconds. 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 duplicates of -the first frame if a video stream starts after the audio stream or to trim any -frames with a negative PTS. - -@end table - -Alternatively, the options can be specified as a flat string: -@var{fps}[:@var{round}]. - -See also the @ref{setpts} filter. - -@subsection Examples - -@itemize -@item -A typical usage in order to set the fps to 25: -@example -fps=fps=25 -@end example - -@item -Sets the fps to 24, using abbreviation and rounding method to round to nearest: -@example -fps=fps=film:round=near -@end example -@end itemize - -@section framestep - -Select one frame every N-th frame. - -This filter accepts the following option: -@table @option -@item step -Select frame after every @code{step} frames. -Allowed values are positive integers higher than 0. Default value is @code{1}. -@end table - -@anchor{frei0r} -@section frei0r - -Apply a frei0r effect to the input video. - -To enable compilation of this filter you need to install the frei0r -header and configure FFmpeg with @code{--enable-frei0r}. - -This filter accepts the following options: - -@table @option - -@item filter_name -The name to the frei0r effect to load. If the environment variable -@env{FREI0R_PATH} is defined, the frei0r effect is searched in each one of the -directories specified by the colon separated list in @env{FREIOR_PATH}, -otherwise in the standard frei0r paths, which are in this order: -@file{HOME/.frei0r-1/lib/}, @file{/usr/local/lib/frei0r-1/}, -@file{/usr/lib/frei0r-1/}. - -@item filter_params -A '|'-separated list of parameters to pass to the frei0r effect. - -@end table - -A frei0r effect parameter can be a boolean (whose values are specified -with "y" and "n"), a double, a color (specified by the syntax -@var{R}/@var{G}/@var{B}, (@var{R}, @var{G}, and @var{B} being float -numbers from 0.0 to 1.0) or by a color description specified in the "Color" -section in the ffmpeg-utils manual), a position (specified by the syntax @var{X}/@var{Y}, -@var{X} and @var{Y} being float numbers) and a string. - -The number and kind of parameters depend on the loaded effect. If an -effect parameter is not specified the default value is set. - -@subsection Examples - -@itemize -@item -Apply the distort0r effect, set the first two double parameters: -@example -frei0r=filter_name=distort0r:filter_params=0.5|0.01 -@end example - -@item -Apply the colordistance effect, take a color as first parameter: -@example -frei0r=colordistance:0.2/0.3/0.4 -frei0r=colordistance:violet -frei0r=colordistance:0x112233 -@end example - -@item -Apply the perspective effect, specify the top left and top right image -positions: -@example -frei0r=perspective:0.2/0.2|0.8/0.2 -@end example -@end itemize - -For more information see: -@url{http://frei0r.dyne.org} - -@section geq - -The filter accepts the following options: - -@table @option -@item lum_expr, lum -Set the luminance expression. -@item cb_expr, cb -Set the chrominance blue expression. -@item cr_expr, cr -Set the chrominance red expression. -@item alpha_expr, a -Set the alpha expression. -@item red_expr, r -Set the red expression. -@item green_expr, g -Set the green expression. -@item blue_expr, b -Set the blue expression. -@end table - -The colorspace is selected according to the specified options. If one -of the @option{lum_expr}, @option{cb_expr}, or @option{cr_expr} -options is specified, the filter will automatically select a YCbCr -colorspace. If one of the @option{red_expr}, @option{green_expr}, or -@option{blue_expr} options is specified, it will select an RGB -colorspace. - -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 -to the luminance expression. - -The expressions can use the following variables and functions: - -@table @option -@item N -The sequential number of the filtered frame, starting from @code{0}. - -@item X -@item Y -The coordinates of the current sample. - -@item W -@item H -The width and height of the image. - -@item SW -@item SH -Width and height scale depending on the currently filtered plane. It is the -ratio between the corresponding luma plane number of pixels and the current -plane ones. E.g. for YUV4:2:0 the values are @code{1,1} for the luma plane, and -@code{0.5,0.5} for chroma planes. - -@item T -Time of the current frame, expressed in seconds. - -@item p(x, y) -Return the value of the pixel at location (@var{x},@var{y}) of the current -plane. - -@item lum(x, y) -Return the value of the pixel at location (@var{x},@var{y}) of the luminance -plane. - -@item cb(x, y) -Return the value of the pixel at location (@var{x},@var{y}) of the -blue-difference chroma plane. Return 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. Return 0 if there is no such plane. - -@item r(x, y) -@item g(x, y) -@item b(x, y) -Return the value of the pixel at location (@var{x},@var{y}) of the -red/green/blue component. Return 0 if there is no such component. - -@item alpha(x, y) -Return the value of the pixel at location (@var{x},@var{y}) of the alpha -plane. Return 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 - -@item -Generate a quick emboss effect: -@example -format=gray,geq=lum_expr='(p(X,Y)+(256-p(X-4,Y-4)))/2' -@end example - -@item -Modify RGB components depending on pixel position: -@example -geq=r='X/W*r(X,Y)':g='(1-X/W)*g(X,Y)':b='(H-Y)/H*b(X,Y)' -@end example -@end itemize - -@section gradfun - -Fix the banding artifacts that are sometimes introduced into nearly flat -regions by truncation to 8bit color depth. -Interpolate the gradients that should go where the bands are, and -dither them. - -This filter is designed for playback only. Do not use it prior to -lossy compression, because compression tends to lose the dither and -bring back the bands. - -This filter accepts the following options: - -@table @option - -@item strength -The maximum amount by which the filter will change any one pixel. Also the -threshold for detecting nearly flat regions. Acceptable values range from .51 to -64, default value is 1.2, out-of-range values will be clipped to the valid -range. - -@item radius -The neighborhood to fit the gradient to. A larger radius makes for smoother -gradients, but also prevents the filter from modifying the pixels near detailed -regions. Acceptable values are 8-32, default value is 16, out-of-range values -will be clipped to the valid range. - -@end table - -Alternatively, the options can be specified as a flat string: -@var{strength}[:@var{radius}] - -@subsection Examples - -@itemize -@item -Apply the filter with a @code{3.5} strength and radius of @code{8}: -@example -gradfun=3.5:8 -@end example - -@item -Specify radius, omitting the strength (which will fall-back to the default -value): -@example -gradfun=radius=8 -@end example - -@end itemize - -@anchor{haldclut} -@section haldclut - -Apply a Hald CLUT to a video stream. - -First input is the video stream to process, and second one is the Hald CLUT. -The Hald CLUT input can be a simple picture or a complete video stream. - -The filter accepts the following options: - -@table @option -@item shortest -Force termination when the shortest input terminates. Default is @code{0}. -@item repeatlast -Continue applying the last CLUT after the end of the stream. A value of -@code{0} disable the filter after the last frame of the CLUT is reached. -Default is @code{1}. -@end table - -@code{haldclut} also has the same interpolation options as @ref{lut3d} (both -filters share the same internals). - -More information about the Hald CLUT can be found on Eskil Steenberg's website -(Hald CLUT author) at @url{http://www.quelsolaar.com/technology/clut.html}. - -@subsection Workflow examples - -@subsubsection Hald CLUT video stream - -Generate an identity Hald CLUT stream altered with various effects: -@example -ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf "hue=H=2*PI*t:s=sin(2*PI*t)+1, curves=cross_process" -t 10 -c:v ffv1 clut.nut -@end example - -Note: make sure you use a lossless codec. - -Then use it with @code{haldclut} to apply it on some random stream: -@example -ffmpeg -f lavfi -i mandelbrot -i clut.nut -filter_complex '[0][1] haldclut' -t 20 mandelclut.mkv -@end example - -The Hald CLUT will be applied to the 10 first seconds (duration of -@file{clut.nut}), then the latest picture of that CLUT stream will be applied -to the remaining frames of the @code{mandelbrot} stream. - -@subsubsection Hald CLUT with preview - -A Hald CLUT is supposed to be a squared image of @code{Level*Level*Level} by -@code{Level*Level*Level} pixels. For a given Hald CLUT, FFmpeg will select the -biggest possible square starting at the top left of the picture. The remaining -padding pixels (bottom or right) will be ignored. This area can be used to add -a preview of the Hald CLUT. - -Typically, the following generated Hald CLUT will be supported by the -@code{haldclut} filter: - -@example -ffmpeg -f lavfi -i @ref{haldclutsrc}=8 -vf " - pad=iw+320 [padded_clut]; - smptebars=s=320x256, split [a][b]; - [padded_clut][a] overlay=W-320:h, curves=color_negative [main]; - [main][b] overlay=W-320" -frames:v 1 clut.png -@end example - -It contains the original and a preview of the effect of the CLUT: SMPTE color -bars are displayed on the right-top, and below the same color bars processed by -the color changes. - -Then, the effect of this Hald CLUT can be visualized with: -@example -ffplay input.mkv -vf "movie=clut.png, [in] haldclut" -@end example - -@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 the following 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 options: - -@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 R, G, B 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 waveform_mirror -Set mirroring mode for @code{waveform}. @code{0} means unmirrored, @code{1} -means mirrored. In mirrored mode, higher values will be represented on the left -side for @code{row} mode and at the top for @code{column} mode. Default is -@code{0} (unmirrored). - -@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}. - -@item levels_mode -Set mode for @code{levels}. Can be either @code{linear}, or @code{logarithmic}. -Default is @code{linear}. -@end table - -@subsection Examples - -@itemize - -@item -Calculate and draw histogram: -@example -ffplay -i input -vf histogram -@end example - -@end itemize - -@anchor{hqdn3d} -@section hqdn3d - -High precision/quality 3d denoise filter. This filter aims to reduce -image noise producing smooth images and making still images really -still. It should enhance compressibility. - -It accepts the following optional parameters: - -@table @option -@item luma_spatial -a non-negative float number which specifies spatial luma strength, -defaults to 4.0 - -@item chroma_spatial -a non-negative float number which specifies spatial chroma strength, -defaults to 3.0*@var{luma_spatial}/4.0 - -@item luma_tmp -a float number which specifies luma temporal strength, defaults to -6.0*@var{luma_spatial}/4.0 - -@item chroma_tmp -a float number which specifies chroma temporal strength, defaults to -@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial} -@end table - -@section hue - -Modify the hue and/or the saturation of the input. - -This filter accepts the following options: - -@table @option -@item h -Specify the hue angle as a number of degrees. It accepts an expression, -and defaults to "0". - -@item s -Specify the saturation in the [-10,10] range. It accepts an expression and -defaults to "1". - -@item H -Specify the hue angle as a number of radians. It accepts an -expression, and defaults to "0". - -@item b -Specify the brightness in the [-10,10] range. It accepts an expression and -defaults to "0". -@end table - -@option{h} and @option{H} are mutually exclusive, and can't be -specified at the same time. - -The @option{b}, @option{h}, @option{H} and @option{s} option values 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 - -@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 -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 commands: -@table @option -@item b -@item s -@item h -@item H -Modify the hue and/or the saturation and/or brightness of the input video. -The command accepts the same syntax of the corresponding option. - -If the specified expression is not valid, 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. - -The filter accepts the following options: - -@table @option -@item intl_thres -Set interlacing threshold. -@item prog_thres -Set progressive threshold. -@end table - -@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. - -The filter accepts the following options: - -@table @option -@item luma_mode, l -@item chroma_mode, c -@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 interlace - -Simple interlacing filter from progressive contents. This interleaves upper (or -lower) lines from odd frames with lower (or upper) lines from even frames, -halving the frame rate and preserving image height. - -@example - Original Original New Frame - Frame 'j' Frame 'j+1' (tff) - ========== =========== ================== - Line 0 --------------------> Frame 'j' Line 0 - Line 1 Line 1 ----> Frame 'j+1' Line 1 - Line 2 ---------------------> Frame 'j' Line 2 - Line 3 Line 3 ----> Frame 'j+1' Line 3 - ... ... ... -New Frame + 1 will be generated by Frame 'j+2' and Frame 'j+3' and so on -@end example - -It accepts the following optional parameters: - -@table @option -@item scan -determines whether the interlaced frame is taken from the even (tff - default) -or odd (bff) lines of the progressive frame. - -@item lowpass -Enable (default) or disable the vertical lowpass filter to avoid twitter -interlacing and reduce moire patterns. -@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. - -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 - -@anchor{lut3d} -@section lut3d - -Apply a 3D LUT to an input video. - -The filter accepts the following options: - -@table @option -@item file -Set the 3D LUT file name. - -Currently supported formats: -@table @samp -@item 3dl -AfterEffects -@item cube -Iridas -@item dat -DaVinci -@item m3d -Pandora -@end table -@item interp -Select interpolation mode. - -Available values are: - -@table @samp -@item nearest -Use values from the nearest defined point. -@item trilinear -Interpolate values using the 8 points defining a cube. -@item tetrahedral -Interpolate values using a tetrahedron. -@end table -@end table - -@section lut, lutrgb, lutyuv - -Compute a look-up table for binding each pixel component input value -to an output value, and apply it to input video. - -@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb} -to an RGB input video. - -These filters accept the following 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 - -@item r -set red component expression -@item g -set green component expression -@item b -set blue component expression -@item a -alpha component expression - -@item y -set Y/luminance component expression -@item u -set U/Cb component expression -@item v -set V/Cr component expression -@end table - -Each of them specifies the expression to use for computing the lookup table for -the corresponding pixel component values. - -The exact component associated to each of the @var{c*} options depends on the -format in input. - -The @var{lut} filter requires either YUV or RGB pixel formats in input, -@var{lutrgb} requires RGB pixel formats in input, and @var{lutyuv} requires YUV. - -The expressions can contain the following constants and functions: - -@table @option -@item w -@item 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 mergeplanes - -Merge color channel components from several video streams. - -The filter accepts up to 4 input streams, and merge selected input -planes to the output video. - -This filter accepts the following options: -@table @option -@item mapping -Set input to output plane mapping. Default is @code{0}. - -The mappings is specified as a bitmap. It should be specified as a -hexadecimal number in the form 0xAa[Bb[Cc[Dd]]]. 'Aa' describes the -mapping for the first plane of the output stream. 'A' sets the number of -the input stream to use (from 0 to 3), and 'a' the plane number of the -corresponding input to use (from 0 to 3). The rest of the mappings is -similar, 'Bb' describes the mapping for the output stream second -plane, 'Cc' describes the mapping for the output stream third plane and -'Dd' describes the mapping for the output stream fourth plane. - -@item format -Set output pixel format. Default is @code{yuva444p}. -@end table - -@subsection Examples - -@itemize -@item -Merge three gray video streams of same width and height into single video stream: -@example -[a0][a1][a2]mergeplanes=0x001020:yuv444p -@end example - -@item -Merge 1st yuv444p stream and 2nd gray video stream into yuva444p video stream: -@example -[a0][a1]mergeplanes=0x00010210:yuva444p -@end example - -@item -Swap Y and A plane in yuva444p stream: -@example -format=yuva444p,mergeplanes=0x03010200:yuva444p -@end example - -@item -Swap U and V plane in yuv420p stream: -@example -format=yuv420p,mergeplanes=0x000201:yuv420p -@end example - -@item -Cast a rgb24 clip to yuv444p: -@example -format=rgb24,mergeplanes=0x000102:yuv444p -@end example -@end itemize - -@section mcdeint - -Apply motion-compensation deinterlacing. - -It needs one field per frame as input and must thus be used together -with yadif=1/3 or equivalent. - -This filter accepts the following options: -@table @option -@item mode -Set the deinterlacing mode. - -It accepts one of the following values: -@table @samp -@item fast -@item medium -@item slow -use iterative motion estimation -@item extra_slow -like @samp{slow}, but use multiple reference frames. -@end table -Default value is @samp{fast}. - -@item parity -Set the picture field parity assumed for the input video. It must be -one of the following values: - -@table @samp -@item 0, tff -assume top field first -@item 1, bff -assume bottom field first -@end table - -Default value is @samp{bff}. - -@item qp -Set per-block quantization parameter (QP) used by the internal -encoder. - -Higher values should result in a smoother motion vector field but less -optimal individual vectors. Default value is 1. -@end table - -@section mp - -Apply an MPlayer filter to the input video. - -This filter provides a wrapper around some 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 filter 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 eq2 -@item eq -@item fspp -@item ilpack -@item pp7 -@item softpulldown -@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 mpdecimate - -Drop frames that do not differ greatly from the previous frame in -order to reduce frame rate. - -The main use of this filter is for very-low-bitrate encoding -(e.g. streaming over dialup modem), but it could in theory be used for -fixing movies that were inverse-telecined incorrectly. - -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 negate - -Negate input video. - -This filter accepts an integer in input, if non-zero it negates the -alpha component (if available). The default value in input is 0. - -@section noformat - -Force libavfilter not to use any of the specified pixel formats for the -input to the next filter. - -This filter accepts the following parameters: -@table @option - -@item pix_fmts -A '|'-separated list of pixel format names, for example -"pix_fmts=yuv420p|monow|rgb24". - -@end table - -@subsection Examples - -@itemize -@item -Force libavfilter to use a format different from @var{yuv420p} for the -input to the vflip filter: -@example -noformat=pix_fmts=yuv420p,vflip -@end example - -@item -Convert the input video to any of the formats not contained in the list: -@example -noformat=yuv420p|yuv444p|yuv410p -@end example -@end itemize - -@section noise - -Add noise on video input frame. - -The filter accepts the following options: - -@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 t -temporal noise (noise pattern changes between frames) -@item u -uniform noise (gaussian otherwise) -@end table -@end table - -@subsection Examples - -Add temporal and uniform noise to input video: -@example -noise=alls=20:allf=t+u -@end example - -@section null - -Pass the video source unchanged to the output. - -@section ocv - -Apply video transform using libopencv. - -To enable this filter install libopencv library and headers and -configure FFmpeg with @code{--enable-libopencv}. - -This filter accepts the following parameters: - -@table @option - -@item filter_name -The name of the libopencv filter to apply. - -@item filter_params -The parameters to pass to the libopencv filter. If not specified the default -values are assumed. - -@end table - -Refer to the official libopencv documentation for more precise -information: -@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html} - -Follows the list of supported libopencv filters. - -@anchor{dilate} -@subsection dilate - -Dilate an image by using a specific structuring element. -This filter corresponds to the libopencv function @code{cvDilate}. - -It accepts the parameters: @var{struct_el}|@var{nb_iterations}. - -@var{struct_el} represents a structuring element, and has the syntax: -@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape} - -@var{cols} and @var{rows} represent the number of columns and rows of -the structuring element, @var{anchor_x} and @var{anchor_y} the anchor -point, and @var{shape} the shape for the structuring element, and -can be one of the values "rect", "cross", "ellipse", "custom". - -If the value for @var{shape} is "custom", it must be followed by a -string of the form "=@var{filename}". The file with name -@var{filename} is assumed to represent a binary image, with each -printable character corresponding to a bright pixel. When a custom -@var{shape} is used, @var{cols} and @var{rows} are ignored, the number -or columns and rows of the read file are assumed instead. - -The default value for @var{struct_el} is "3x3+0x0/rect". - -@var{nb_iterations} specifies the number of times the transform is -applied to the image, and defaults to 1. - -Follow some example: -@example -# use the default values -ocv=dilate - -# dilate using a structuring element with a 5x5 cross, iterate two times -ocv=filter_name=dilate:filter_params=5x5+2x2/cross|2 - -# read the shape from the file diamond.shape, iterate two times -# the file diamond.shape may contain a pattern of characters like this: -# * -# *** -# ***** -# *** -# * -# the specified cols and rows are ignored (but not the anchor point coordinates) -ocv=dilate:0x0+2x2/custom=diamond.shape|2 -@end example - -@subsection erode - -Erode an image by using a specific structuring element. -This filter corresponds to the libopencv function @code{cvErode}. - -The filter accepts the parameters: @var{struct_el}:@var{nb_iterations}, -with the same syntax and semantics as the @ref{dilate} filter. - -@subsection smooth - -Smooth the input video. - -The filter takes the following parameters: -@var{type}|@var{param1}|@var{param2}|@var{param3}|@var{param4}. - -@var{type} is the type of smooth filter to apply, and can be one of -the following values: "blur", "blur_no_scale", "median", "gaussian", -"bilateral". The default value is "gaussian". - -@var{param1}, @var{param2}, @var{param3}, and @var{param4} are -parameters whose meanings depend on smooth type. @var{param1} and -@var{param2} accept integer positive values or 0, @var{param3} and -@var{param4} accept float values. - -The default value for @var{param1} is 3, the default value for the -other parameters is 0. - -These parameters correspond to the parameters assigned to the -libopencv function @code{cvSmooth}. - -@anchor{overlay} -@section overlay - -Overlay one video on top of another. - -It takes two inputs and one output, the first input is the "main" -video on which the second input is overlayed. - -This filter accepts the following parameters: - -A description of the accepted options follows. - -@table @option -@item x -@item y -Set the expression for the x and y coordinates of the overlayed video -on the main video. Default value is "0" for both expressions. In case -the expression is invalid, it is set to a huge value (meaning that the -overlay will not be displayed within the output visible area). - -@item eval -Set when the expressions for @option{x}, and @option{y} are evaluated. - -It accepts the following values: -@table @samp -@item init -only evaluate expressions once during the filter initialization or -when a command is processed - -@item frame -evaluate expressions for each incoming frame -@end table - -Default value is @samp{frame}. - -@item shortest -If set to 1, force the output to terminate when the shortest input -terminates. Default value is 0. - -@item format -Set the format for the output video. - -It accepts the following values: -@table @samp -@item yuv420 -force YUV420 output - -@item yuv444 -force YUV444 output - -@item rgb -force RGB output -@end table - -Default value is @samp{yuv420}. - -@item rgb @emph{(deprecated)} -If set to 1, force the filter to accept inputs in the RGB -color space. Default value is 0. This option is deprecated, use -@option{format} instead. - -@item repeatlast -If set to 1, force the filter to draw the last overlay frame over the -main input until the end of the stream. A value of 0 disables this -behavior. Default value is 1. -@end table - -The @option{x}, and @option{y} expressions can contain the following -parameters. - -@table @option -@item main_w, W -@item main_h, H -main input width and height - -@item overlay_w, w -@item overlay_h, h -overlay input width and height - -@item x -@item y -the computed values for @var{x} and @var{y}. They are evaluated for -each new frame. - -@item hsub -@item vsub -horizontal and vertical chroma subsample values of the output -format. For example for the pixel format "yuv422p" @var{hsub} is 2 and -@var{vsub} is 1. - -@item n -the number of input frame, starting from 0 - -@item pos -the position in the file of the input frame, NAN if unknown - -@item t -timestamp expressed in seconds, NAN if the input timestamp is unknown -@end table - -Note that the @var{n}, @var{pos}, @var{t} variables are available only -when evaluation is done @emph{per frame}, and will evaluate to NAN -when @option{eval} is set to @samp{init}. - -Be aware that frames are taken from each input video in timestamp -order, hence, if their initial timestamps differ, it is a good idea -to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to -have them begin in the same zero timestamp, as it does the example for -the @var{movie} filter. - -You can chain together more overlays but you should test the -efficiency of such approach. - -@subsection Commands - -This filter supports the following commands: -@table @option -@item x -@item y -Modify the x and y of the overlay input. -The command accepts the same syntax of the corresponding option. - -If the specified expression is not valid, it is kept at its current -value. -@end table - -@subsection Examples - -@itemize -@item -Draw the overlay at 10 pixels from the bottom right corner of the main -video: -@example -overlay=main_w-overlay_w-10:main_h-overlay_h-10 -@end example - -Using named options the example above becomes: -@example -overlay=x=main_w-overlay_w-10:y=main_h-overlay_h-10 -@end example - -@item -Insert a transparent PNG logo in the bottom left corner of the input, -using the @command{ffmpeg} tool with the @code{-filter_complex} option: -@example -ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output -@end example - -@item -Insert 2 different transparent PNG logos (second logo on bottom -right corner) using the @command{ffmpeg} tool: -@example -ffmpeg -i input -i logo1 -i logo2 -filter_complex 'overlay=x=10:y=H-h-10,overlay=x=W-w-10:y=H-h-10' output -@end example - -@item -Add a transparent color layer on top of the main video, @code{WxH} -must specify the size of the main input to the overlay filter: -@example -color=color=red@@.3:size=WxH [over]; [in][over] overlay [out] -@end example - -@item -Play an original video and a filtered version (here with the deshake -filter) side by side using the @command{ffplay} tool: -@example -ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w' -@end example - -The above command is the same as: -@example -ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w' -@end example - -@item -Make a sliding overlay appearing from the left to the right top part of the -screen starting since time 2: -@example -overlay=x='if(gte(t,2), -w+(t-2)*20, NAN)':y=0 -@end example - -@item -Compose output by putting two input videos side to side: -@example -ffmpeg -i left.avi -i right.avi -filter_complex " -nullsrc=size=200x100 [background]; -[0:v] setpts=PTS-STARTPTS, scale=100x100 [left]; -[1:v] setpts=PTS-STARTPTS, scale=100x100 [right]; -[background][left] overlay=shortest=1 [background+left]; -[background+left][right] overlay=shortest=1:x=100 [left+right] -" -@end example - -@item -Chain several overlays in cascade: -@example -nullsrc=s=200x200 [bg]; -testsrc=s=100x100, split=4 [in0][in1][in2][in3]; -[in0] lutrgb=r=0, [bg] overlay=0:0 [mid0]; -[in1] lutrgb=g=0, [mid0] overlay=100:0 [mid1]; -[in2] lutrgb=b=0, [mid1] overlay=0:100 [mid2]; -[in3] null, [mid2] overlay=100:100 [out0] -@end example - -@end itemize - -@section owdenoise - -Apply Overcomplete Wavelet denoiser. - -The filter accepts the following options: - -@table @option -@item depth -Set depth. - -Larger depth values will denoise lower frequency components more, but -slow down filtering. - -Must be an int in the range 8-16, default is @code{8}. - -@item luma_strength, ls -Set luma strength. - -Must be a double value in the range 0-1000, default is @code{1.0}. - -@item chroma_strength, cs -Set chroma strength. - -Must be a double value in the range 0-1000, default is @code{1.0}. -@end table - -@section pad - -Add paddings to the input image, and place the original input at the -given coordinates @var{x}, @var{y}. - -This filter accepts the following parameters: - -@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. For the syntax of this option, -check the "Color" section in the ffmpeg-utils manual. - -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 -@item in_h -the input video width and height - -@item iw -@item ih -same as @var{in_w} and @var{in_h} - -@item out_w -@item 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 -@item oh -same as @var{out_w} and @var{out_h} - -@item x -@item 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 -@item 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 perspective - -Correct perspective of video not recorded perpendicular to the screen. - -A description of the accepted parameters follows. - -@table @option -@item x0 -@item y0 -@item x1 -@item y1 -@item x2 -@item y2 -@item x3 -@item y3 -Set coordinates expression for top left, top right, bottom left and bottom right corners. -Default values are @code{0:0:W:0:0:H:W:H} with which perspective will remain unchanged. - -The expressions can use the following variables: - -@table @option -@item W -@item H -the width and height of video frame. -@end table - -@item interpolation -Set interpolation for perspective correction. - -It accepts the following values: -@table @samp -@item linear -@item cubic -@end table - -Default value is @samp{linear}. -@end table - -@section phase - -Delay interlaced video by one field time so that the field order changes. - -The intended use is to fix PAL movies that have been captured with the -opposite field order to the film-to-video transfer. - -A description of the accepted parameters follows. - -@table @option -@item mode -Set phase mode. - -It accepts the following values: -@table @samp -@item t -Capture field order top-first, transfer bottom-first. -Filter will delay the bottom field. - -@item b -Capture field order bottom-first, transfer top-first. -Filter will delay the top field. - -@item p -Capture and transfer with the same field order. This mode only exists -for the documentation of the other options to refer to, but if you -actually select it, the filter will faithfully do nothing. - -@item a -Capture field order determined automatically by field flags, transfer -opposite. -Filter selects among @samp{t} and @samp{b} modes on a frame by frame -basis using field flags. If no field information is available, -then this works just like @samp{u}. - -@item u -Capture unknown or varying, transfer opposite. -Filter selects among @samp{t} and @samp{b} on a frame by frame basis by -analyzing the images and selecting the alternative that produces best -match between the fields. - -@item T -Capture top-first, transfer unknown or varying. -Filter selects among @samp{t} and @samp{p} using image analysis. - -@item B -Capture bottom-first, transfer unknown or varying. -Filter selects among @samp{b} and @samp{p} using image analysis. - -@item A -Capture determined by field flags, transfer unknown or varying. -Filter selects among @samp{t}, @samp{b} and @samp{p} using field flags and -image analysis. If no field information is available, then this works just -like @samp{U}. This is the default mode. - -@item U -Both capture and transfer unknown or varying. -Filter selects among @samp{t}, @samp{b} and @samp{p} using image analysis only. -@end table -@end table - -@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. - -The filters accept the following options: - -@table @option -@item subfilters -Set postprocessing subfilters string. -@end table - -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 psnr - -Obtain the average, maximum and minimum PSNR (Peak Signal to Noise -Ratio) between two input videos. - -This filter takes in input two input videos, the first input is -considered the "main" source and is passed unchanged to the -output. The second input is used as a "reference" video for computing -the PSNR. - -Both video inputs must have the same resolution and pixel format for -this filter to work correctly. Also it assumes that both inputs -have the same number of frames, which are compared one by one. - -The obtained average PSNR is printed through the logging system. - -The filter stores the accumulated MSE (mean squared error) of each -frame, and at the end of the processing it is averaged across all frames -equally, and the following formula is applied to obtain the PSNR: - -@example -PSNR = 10*log10(MAX^2/MSE) -@end example - -Where MAX is the average of the maximum values of each component of the -image. - -The description of the accepted parameters follows. - -@table @option -@item stats_file, f -If specified the filter will use the named file to save the PSNR of -each individual frame. -@end table - -The file printed if @var{stats_file} is selected, contains a sequence of -key/value pairs of the form @var{key}:@var{value} for each compared -couple of frames. - -A description of each shown parameter follows: - -@table @option -@item n -sequential number of the input frame, starting from 1 - -@item mse_avg -Mean Square Error pixel-by-pixel average difference of the compared -frames, averaged over all the image components. - -@item mse_y, mse_u, mse_v, mse_r, mse_g, mse_g, mse_a -Mean Square Error pixel-by-pixel average difference of the compared -frames for the component specified by the suffix. - -@item psnr_y, psnr_u, psnr_v, psnr_r, psnr_g, psnr_b, psnr_a -Peak Signal to Noise ratio of the compared frames for the component -specified by the suffix. -@end table - -For example: -@example -movie=ref_movie.mpg, setpts=PTS-STARTPTS [main]; -[main][ref] psnr="stats_file=stats.log" [out] -@end example - -On this example the input file being processed is compared with the -reference file @file{ref_movie.mpg}. The PSNR of each individual frame -is stored in @file{stats.log}. - -@section pullup - -Pulldown reversal (inverse telecine) filter, capable of handling mixed -hard-telecine, 24000/1001 fps progressive, and 30000/1001 fps progressive -content. - -The pullup filter is designed to take advantage of future context in making -its decisions. This filter is stateless in the sense that it does not lock -onto a pattern to follow, but it instead looks forward to the following -fields in order to identify matches and rebuild progressive frames. - -To produce content with an even framerate, insert the fps filter after -pullup, use @code{fps=24000/1001} if the input frame rate is 29.97fps, -@code{fps=24} for 30fps and the (rare) telecined 25fps input. - -The filter accepts the following options: - -@table @option -@item jl -@item jr -@item jt -@item jb -These options set the amount of "junk" to ignore at the left, right, top, and -bottom of the image, respectively. Left and right are in units of 8 pixels, -while top and bottom are in units of 2 lines. -The default is 8 pixels on each side. - -@item sb -Set the strict breaks. Setting this option to 1 will reduce the chances of -filter generating an occasional mismatched frame, but it may also cause an -excessive number of frames to be dropped during high motion sequences. -Conversely, setting it to -1 will make filter match fields more easily. -This may help processing of video where there is slight blurring between -the fields, but may also cause there to be interlaced frames in the output. -Default value is @code{0}. - -@item mp -Set the metric plane to use. It accepts the following values: -@table @samp -@item l -Use luma plane. - -@item u -Use chroma blue plane. - -@item v -Use chroma red plane. -@end table - -This option may be set to use chroma plane instead of the default luma plane -for doing filter's computations. This may improve accuracy on very clean -source material, but more likely will decrease accuracy, especially if there -is chroma noise (rainbow effect) or any grayscale video. -The main purpose of setting @option{mp} to a chroma plane is to reduce CPU -load and make pullup usable in realtime on slow machines. -@end table - -For best results (without duplicated frames in the output file) it is -necessary to change the output frame rate. For example, to inverse -telecine NTSC input: -@example -ffmpeg -i input -vf pullup -r 24000/1001 ... -@end example - -@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. - -The filter accepts the following options: - -@table @option -@item filename, f -Set 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. -@end table - -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 rotate - -Rotate video by an arbitrary angle expressed in radians. - -The filter accepts the following options: - -A description of the optional parameters follows. -@table @option -@item angle, a -Set an expression for the angle by which to rotate the input video -clockwise, expressed as a number of radians. A negative value will -result in a counter-clockwise rotation. By default it is set to "0". - -This expression is evaluated for each frame. - -@item out_w, ow -Set the output width expression, default value is "iw". -This expression is evaluated just once during configuration. - -@item out_h, oh -Set the output height expression, default value is "ih". -This expression is evaluated just once during configuration. - -@item bilinear -Enable bilinear interpolation if set to 1, a value of 0 disables -it. Default value is 1. - -@item fillcolor, c -Set the color used to fill the output area not covered by the rotated -image. For the generalsyntax of this option, check the "Color" section in the -ffmpeg-utils manual. If the special value "none" is selected then no -background is printed (useful for example if the background is never shown). - -Default value is "black". -@end table - -The expressions for the angle and the output size can contain the -following constants and functions: - -@table @option -@item n -sequential number of the input frame, starting from 0. It is always NAN -before the first frame is filtered. - -@item t -time in seconds of the input frame, it is set to 0 when the filter is -configured. It is always NAN before the first frame is filtered. - -@item hsub -@item vsub -horizontal and vertical chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. - -@item in_w, iw -@item in_h, ih -the input video width and heigth - -@item out_w, ow -@item out_h, oh -the output width and heigth, that is the size of the padded area as -specified by the @var{width} and @var{height} expressions - -@item rotw(a) -@item roth(a) -the minimal width/height required for completely containing the input -video rotated by @var{a} radians. - -These are only available when computing the @option{out_w} and -@option{out_h} expressions. -@end table - -@subsection Examples - -@itemize -@item -Rotate the input by PI/6 radians clockwise: -@example -rotate=PI/6 -@end example - -@item -Rotate the input by PI/6 radians counter-clockwise: -@example -rotate=-PI/6 -@end example - -@item -Apply a constant rotation with period T, starting from an angle of PI/3: -@example -rotate=PI/3+2*PI*t/T -@end example - -@item -Make the input video rotation oscillating with a period of T -seconds and an amplitude of A radians: -@example -rotate=A*sin(2*PI/T*t) -@end example - -@item -Rotate the video, output size is choosen so that the whole rotating -input video is always completely contained in the output: -@example -rotate='2*PI*t:ow=hypot(iw,ih):oh=ow' -@end example - -@item -Rotate the video, reduce the output size so that no background is ever -shown: -@example -rotate=2*PI*t:ow='min(iw,ih)/sqrt(2)':oh=ow:c=none -@end example -@end itemize - -@subsection Commands - -The filter supports the following commands: - -@table @option -@item a, angle -Set the angle expression. -The command accepts the same syntax of the corresponding option. - -If the specified expression is not valid, it is kept at its current -value. -@end table - -@section sab - -Apply Shape Adaptive Blur. - -The filter accepts the following options: - -@table @option -@item luma_radius, lr -Set luma blur filter strength, must be a value in range 0.1-4.0, default -value is 1.0. A greater value will result in a more blurred image, and -in slower processing. - -@item luma_pre_filter_radius, lpfr -Set luma pre-filter radius, must be a value in the 0.1-2.0 range, default -value is 1.0. - -@item luma_strength, ls -Set luma maximum difference between pixels to still be considered, must -be a value in the 0.1-100.0 range, default value is 1.0. - -@item chroma_radius, cr -Set chroma blur filter strength, must be a value in range 0.1-4.0. A -greater value will result in a more blurred image, and in slower -processing. - -@item chroma_pre_filter_radius, cpfr -Set chroma pre-filter radius, must be a value in the 0.1-2.0 range. - -@item chroma_strength, cs -Set chroma maximum difference between pixels to still be considered, -must be a value in the 0.1-100.0 range. -@end table - -Each chroma option value, if not explicitly specified, is set to the -corresponding luma option value. - -@anchor{scale} -@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. - -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. - -@subsection Options -The filter accepts the following options, or any of the options -supported by the libswscale scaler. - -See @ref{scaler_options,,the ffmpeg-scaler manual,ffmpeg-scaler} for -the complete list of scaler options. - -@table @option -@item width, w -@item height, h -Set the output video dimension expression. Default value is the input -dimension. - -If the value is 0, the input width is used for the output. - -If one of the values is -1, the scale filter will use a value that -maintains the aspect ratio of the input image, calculated from the -other specified dimension. If both of them are -1, the input size is -used - -See below for the list of accepted constants for use in the dimension -expression. - -@item interl -Set the interlacing mode. It accepts the following values: - -@table @samp -@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 @samp{0}. - -@item flags -Set libswscale scaling flags. See -@ref{sws_flags,,the ffmpeg-scaler manual,ffmpeg-scaler} for the -complete list of values. If not explictly specified the filter applies -the default flags. - -@item size, s -Set the video size. For the syntax of this option, check the "Video size" -section in the ffmpeg-utils manual. - -@item in_color_matrix -@item out_color_matrix -Set in/output YCbCr color space type. - -This allows the autodetected value to be overridden as well as allows forcing -a specific value used for the output and encoder. - -If not specified, the color space type depends on the pixel format. - -Possible values: - -@table @samp -@item auto -Choose automatically. - -@item bt709 -Format conforming to International Telecommunication Union (ITU) -Recommendation BT.709. - -@item fcc -Set color space conforming to the United States Federal Communications -Commission (FCC) Code of Federal Regulations (CFR) Title 47 (2003) 73.682 (a). - -@item bt601 -Set color space conforming to: - -@itemize -@item -ITU Radiocommunication Sector (ITU-R) Recommendation BT.601 - -@item -ITU-R Rec. BT.470-6 (1998) Systems B, B1, and G - -@item -Society of Motion Picture and Television Engineers (SMPTE) ST 170:2004 - -@end itemize - -@item smpte240m -Set color space conforming to SMPTE ST 240:1999. -@end table - -@item in_range -@item out_range -Set in/output YCbCr sample range. - -This allows the autodetected value to be overridden as well as allows forcing -a specific value used for the output and encoder. If not specified, the -range depends on the pixel format. Possible values: - -@table @samp -@item auto -Choose automatically. - -@item jpeg/full/pc -Set full range (0-255 in case of 8-bit luma). - -@item mpeg/tv -Set "MPEG" range (16-235 in case of 8-bit luma). -@end table - -@item force_original_aspect_ratio -Enable decreasing or increasing output video width or height if necessary to -keep the original aspect ratio. Possible values: - -@table @samp -@item disable -Scale the video as specified and disable this feature. - -@item decrease -The output video dimensions will automatically be decreased if needed. - -@item increase -The output video dimensions will automatically be increased if needed. - -@end table - -One useful instance of this option is that when you know a specific device's -maximum allowed resolution, you can use this to limit the output video to -that, while retaining the aspect ratio. For example, device A allows -1280x720 playback, and your video is 1920x800. Using this option (set it to -decrease) and specifying 1280x720 to the command line makes the output -1280x533. - -Please note that this is a different thing than specifying -1 for @option{w} -or @option{h}, you still need to specify the output resolution for this option -to work. - -@end table - -The values of the @option{w} and @option{h} options are expressions -containing the following constants: - -@table @var -@item in_w -@item in_h -the input width and height - -@item iw -@item ih -same as @var{in_w} and @var{in_h} - -@item out_w -@item out_h -the output (scaled) width and height - -@item ow -@item 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. Calculated from @code{(iw / ih) * sar}. - -@item hsub -@item vsub -horizontal and vertical input chroma subsample values. For example for the -pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1. - -@item ohsub -@item ovsub -horizontal and vertical output 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 -Scale the input video to a size of 200x100: -@example -scale=w=200:h=100 -@end example - -This is equivalent to: -@example -scale=200:100 -@end example - -or: -@example -scale=200x100 -@end example - -@item -Specify a size abbreviation for the output size: -@example -scale=qcif -@end example - -which can also be written as: -@example -scale=size=qcif -@end example - -@item -Scale the input to 2x: -@example -scale=w=2*iw:h=2*ih -@end example - -@item -The above is the same as: -@example -scale=2*in_w:2*in_h -@end example - -@item -Scale the input to 2x with forced interlaced scaling: -@example -scale=2*iw:2*ih:interl=1 -@end example - -@item -Scale the input to half size: -@example -scale=w=iw/2:h=ih/2 -@end example - -@item -Increase the width, and set the height to the same size: -@example -scale=3/2*iw:ow -@end example - -@item -Seek for Greek harmony: -@example -scale=iw:1/PHI*iw -scale=ih*PHI:ih -@end example - -@item -Increase the height, and set the width to 3/2 of the height: -@example -scale=w=3/2*oh:h=3/5*ih -@end example - -@item -Increase the size, but make the size a multiple of the chroma -subsample values: -@example -scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub" -@end example - -@item -Increase the width to a maximum of 500 pixels, keep the same input -aspect ratio: -@example -scale=w='min(500\, iw*3/2):h=-1' -@end example -@end itemize - -@section separatefields - -The @code{separatefields} takes a frame-based video input and splits -each frame into its components fields, producing a new half height clip -with twice the frame rate and twice the frame count. - -This filter use field-dominance information in frame to decide which -of each pair of fields to place first in the output. -If it gets it wrong use @ref{setfield} filter before @code{separatefields} filter. - -@section setdar, setsar - -The @code{setdar} filter sets the Display Aspect Ratio for the filter -output video. - -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 filters accept the following options: - -@table @option -@item r, ratio, dar (@code{setdar} only), sar (@code{setsar} only) -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}" is used, the @code{:} character -should be escaped. - -@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}. - -@end table - -The parameter @var{sar} is an expression containing -the following constants: - -@table @option -@item E, PI, PHI -the corresponding mathematical approximated values for e -(euler number), pi (greek PI), phi (golden ratio) - -@item w, h -the input width and height - -@item a -same as @var{w} / @var{h} - -@item sar -input sample aspect ratio - -@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. -@end table - -@subsection Examples - -@itemize - -@item -To change the display aspect ratio to 16:9, specify one of the following: -@example -setdar=dar=1.77777 -setdar=dar=16/9 -setdar=dar=1.77777 -@end example - -@item -To change the sample aspect ratio to 10:11, specify: -@example -setsar=sar=10/11 -@end example - -@item -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 - -@end itemize - -@anchor{setfield} -@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}). - -The filter accepts the following options: - -@table @option - -@item mode -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 -@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. For the syntax of this option, check the "Video size" -section in the ffmpeg-utils manual. - -@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 - -@anchor{smartblur} -@section smartblur - -Blur the input video without impacting the outlines. - -The filter accepts the following options: - -@table @option -@item luma_radius, lr -Set the luma 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 -Set the luma 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 -Set the luma 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. - -@item chroma_radius, cr -Set the 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 chroma_strength, cs -Set the 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 chroma_threshold, ct -Set the 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. - -The filters accept the following options: - -@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) - -@item al -alternating frames (left eye first, right eye second) - -@item ar -alternating frames (right eye first, left eye second) - -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 - -@subsection Examples - -@itemize -@item -Convert input video from side by side parallel to anaglyph yellow/blue dubois: -@example -stereo3d=sbsl:aybd -@end example - -@item -Convert input video from above bellow (left eye above, right eye below) to side by side crosseye. -@example -stereo3d=abl:sbsr -@end example -@end itemize - -@section spp - -Apply a simple postprocessing filter that compresses and decompresses the image -at several (or - in the case of @option{quality} level @code{6} - all) shifts -and average the results. - -The filter accepts the following options: - -@table @option -@item quality -Set quality. This option defines the number of levels for averaging. It accepts -an integer in the range 0-6. If set to @code{0}, the filter will have no -effect. A value of @code{6} means the higher quality. For each increment of -that value the speed drops by a factor of approximately 2. Default value is -@code{3}. - -@item qp -Force a constant quantization parameter. If not set, the filter will use the QP -from the video stream (if available). - -@item mode -Set thresholding mode. Available modes are: - -@table @samp -@item hard -Set hard thresholding (default). -@item soft -Set soft thresholding (better de-ringing effect, but likely blurrier). -@end table - -@item use_bframe_qp -Enable the use of the QP from the B-Frames if set to @code{1}. Using this -option may cause flicker since the B-Frames have often larger QP. Default is -@code{0} (not enabled). -@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. - -The filter accepts the following options: - -@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. For the syntax of this option, check the "Video size" section in -the ffmpeg-utils manual. 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 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 telecine - -Apply telecine process to the video. - -This filter accepts the following options: - -@table @option -@item first_field -@table @samp -@item top, t -top field first -@item bottom, b -bottom field first -The default value is @code{top}. -@end table - -@item pattern -A string of numbers representing the pulldown pattern you wish to apply. -The default value is @code{23}. -@end table - -@example -Some typical patterns: - -NTSC output (30i): -27.5p: 32222 -24p: 23 (classic) -24p: 2332 (preferred) -20p: 33 -18p: 334 -16p: 3444 - -PAL output (25i): -27.5p: 12222 -24p: 222222222223 ("Euro pulldown") -16.67p: 33 -16p: 33333334 -@end example - -@section thumbnail -Select the most representative frame in a given sequence of consecutive frames. - -The filter accepts the following options: - -@table @option -@item n -Set the frames batch size to analyze; in a set of @var{n} frames, the filter -will pick one of them, and then handle the next batch of @var{n} frames until -the end. Default is @code{100}. -@end table - -Since the filter keeps track of the whole frames sequence, a bigger @var{n} -value will result in a higher memory usage, so a high value is not recommended. - -@subsection Examples - -@itemize -@item -Extract one picture each 50 frames: -@example -thumbnail=50 -@end example - -@item -Complete example of a thumbnail creation with @command{ffmpeg}: -@example -ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png -@end example -@end itemize - -@section tile - -Tile several successive frames together. - -The filter accepts the following options: - -@table @option - -@item layout -Set the grid size (i.e. the number of lines and columns). For the syntax of -this option, check the "Video size" section in the ffmpeg-utils manual. - -@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. - -@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 color -Specify the color of the unused areaFor the syntax of this option, check the -"Color" section in the ffmpeg-utils manual. The default value of @var{color} -is "black". -@end table - -@subsection Examples - -@itemize -@item -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. - -@item -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 -@end itemize - -@section tinterlace - -Perform various types of temporal field interlacing. - -Frames are counted starting from 1, so the first input frame is -considered odd. - -The filter accepts the following options: - -@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 frame rate. - -@item drop_odd, 1 -Only output even frames, odd frames are dropped, generating a frame with -unchanged height at half frame rate. - -@item drop_even, 2 -Only output odd frames, even frames are dropped, generating a frame with -unchanged height at half frame rate. - -@item pad, 3 -Expand each frame to full height, but pad alternate lines with black, -generating a frame with double height at the same input frame rate. - -@item interleave_top, 4 -Interleave the upper field from odd frames with the lower field from -even frames, generating a frame with unchanged height at half frame rate. - -@item interleave_bottom, 5 -Interleave the lower field from odd frames with the upper field from -even frames, generating a frame with unchanged height at half frame rate. - -@item interlacex2, 6 -Double frame rate with unchanged height. Frames are inserted each -containing the second temporal field from the previous input frame and -the first temporal field from the next input frame. This mode relies on -the top_field_first flag. Useful for interlaced video displays with no -field synchronisation. -@end table - -Numeric values are deprecated but are accepted for backward -compatibility reasons. - -Default mode is @code{merge}. - -@item flags -Specify flags influencing the filter process. - -Available value for @var{flags} is: - -@table @option -@item low_pass_filter, vlfp -Enable vertical low-pass filtering in the filter. -Vertical low-pass filtering is required when creating an interlaced -destination from a progressive source which contains high-frequency -vertical detail. Filtering will reduce interlace 'twitter' and Moire -patterning. - -Vertical low-pass filtering can only be enabled for @option{mode} -@var{interleave_top} and @var{interleave_bottom}. - -@end table -@end table - -@section transpose - -Transpose rows with columns in the input video and optionally flip it. - -This filter accepts the following options: - -@table @option - -@item dir -Specify the transposition direction. - -Can assume the following values: -@table @samp -@item 0, 4, cclock_flip -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, clock -Rotate by 90 degrees clockwise, that is: -@example -L.R l.L -. . -> . . -l.r r.R -@end example - -@item 2, 6, cclock -Rotate by 90 degrees counterclockwise, that is: -@example -L.R R.r -. . -> . . -l.r L.l -@end example - -@item 3, 7, clock_flip -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. - -Numerical values are deprecated, and should be dropped in favor of -symbolic constants. - -@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 trim -Trim the input so that the output contains one continuous subpart of the input. - -This filter accepts the following options: -@table @option -@item start -Specify time of the start of the kept section, i.e. the frame with the -timestamp @var{start} will be the first frame in the output. - -@item end -Specify time of the first frame that will be dropped, i.e. the frame -immediately preceding the one with the timestamp @var{end} will be the last -frame in the output. - -@item start_pts -Same as @var{start}, except this option sets the start timestamp in timebase -units instead of seconds. - -@item end_pts -Same as @var{end}, except this option sets the end timestamp in timebase units -instead of seconds. - -@item duration -Specify maximum duration of the output. - -@item start_frame -Number of the first frame that should be passed to output. - -@item end_frame -Number of the first frame that should be dropped. -@end table - -@option{start}, @option{end}, @option{duration} are expressed as time -duration specifications, check the "Time duration" section in the -ffmpeg-utils manual. - -Note that the first two sets of the start/end options and the @option{duration} -option look at the frame timestamp, while the _frame variants simply count the -frames that pass through the filter. Also note that this filter does not modify -the timestamps. If you wish that the output timestamps start at zero, insert a -setpts filter after the trim filter. - -If multiple start or end options are set, this filter tries to be greedy and -keep all the frames that match at least one of the specified constraints. To keep -only the part that matches all the constraints at once, chain multiple trim -filters. - -The defaults are such that all the input is kept. So it is possible to set e.g. -just the end values to keep everything before the specified time. - -Examples: -@itemize -@item -drop everything except the second minute of input -@example -ffmpeg -i INPUT -vf trim=60:120 -@end example - -@item -keep only the first second -@example -ffmpeg -i INPUT -vf trim=duration=1 -@end example - -@end itemize - - -@section unsharp - -Sharpen or blur the input video. - -It accepts the following parameters: - -@table @option -@item luma_msize_x, lx -Set the luma matrix horizontal size. It must be an odd integer between -3 and 63, default value is 5. - -@item luma_msize_y, ly -Set the luma matrix vertical size. It must be an odd integer between 3 -and 63, default value is 5. - -@item luma_amount, la -Set the luma 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. - -@item chroma_msize_x, cx -Set the chroma matrix horizontal size. It must be an odd integer -between 3 and 63, default value is 5. - -@item chroma_msize_y, cy -Set the chroma matrix vertical size. It must be an odd integer -between 3 and 63, default value is 5. - -@item chroma_amount, ca -Set the 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 0.0. - -@item opencl -If set to 1, specify using OpenCL capabilities, only available if -FFmpeg was configured with @code{--enable-opencl}. Default value is 0. - -@end table - -All parameters are optional and default to the equivalent of the -string '5:5:1.0:5:5:0.0'. - -@subsection Examples - -@itemize -@item -Apply strong luma sharpen effect: -@example -unsharp=luma_msize_x=7:luma_msize_y=7:luma_amount=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 - -@anchor{vidstabdetect} -@section vidstabdetect - -Analyze video stabilization/deshaking. Perform pass 1 of 2, see -@ref{vidstabtransform} for pass 2. - -This filter generates a file with relative translation and rotation -transform information about subsequent frames, which is then used by -the @ref{vidstabtransform} filter. - -To enable compilation of this filter you need to configure FFmpeg with -@code{--enable-libvidstab}. - -This filter accepts the following options: - -@table @option -@item result -Set the path to the file used to write the transforms information. -Default value is @file{transforms.trf}. - -@item shakiness -Set how shaky the video is and how quick the camera is. It accepts an -integer in the range 1-10, a value of 1 means little shakiness, a -value of 10 means strong shakiness. Default value is 5. - -@item accuracy -Set the accuracy of the detection process. It must be a value in the -range 1-15. A value of 1 means low accuracy, a value of 15 means high -accuracy. Default value is 9. - -@item stepsize -Set stepsize of the search process. The region around minimum is -scanned with 1 pixel resolution. Default value is 6. - -@item mincontrast -Set minimum contrast. Below this value a local measurement field is -discarded. Must be a floating point value in the range 0-1. Default -value is 0.3. - -@item tripod -Set reference frame number for tripod mode. - -If enabled, the motion of the frames is compared to a reference frame -in the filtered stream, identified by the specified number. The idea -is to compensate all movements in a more-or-less static scene and keep -the camera view absolutely still. - -If set to 0, it is disabled. The frames are counted starting from 1. - -@item show -Show fields and transforms in the resulting frames. It accepts an -integer in the range 0-2. Default value is 0, which disables any -visualization. -@end table - -@subsection Examples - -@itemize -@item -Use default values: -@example -vidstabdetect -@end example - -@item -Analyze strongly shaky movie and put the results in file -@file{mytransforms.trf}: -@example -vidstabdetect=shakiness=10:accuracy=15:result="mytransforms.trf" -@end example - -@item -Visualize the result of internal transformations in the resulting -video: -@example -vidstabdetect=show=1 -@end example - -@item -Analyze a video with medium shakiness using @command{ffmpeg}: -@example -ffmpeg -i input -vf vidstabdetect=shakiness=5:show=1 dummy.avi -@end example -@end itemize - -@anchor{vidstabtransform} -@section vidstabtransform - -Video stabilization/deshaking: pass 2 of 2, -see @ref{vidstabdetect} for pass 1. - -Read a file with transform information for each frame and -apply/compensate them. Together with the @ref{vidstabdetect} -filter this can be used to deshake videos. See also -@url{http://public.hronopik.de/vid.stab}. It is important to also use -the unsharp filter, see below. - -To enable compilation of this filter you need to configure FFmpeg with -@code{--enable-libvidstab}. - -This filter accepts the following options: - -@table @option - -@item input -path to the file used to read the transforms (default: @file{transforms.trf}) - -@item smoothing -number of frames (value*2 + 1) used for lowpass filtering the camera movements -(default: 10). For example a number of 10 means that 21 frames are used -(10 in the past and 10 in the future) to smoothen the motion in the -video. A larger values leads to a smoother video, but limits the -acceleration of the camera (pan/tilt movements). - -@item maxshift -maximal number of pixels to translate frames (default: -1 no limit) - -@item maxangle -maximal angle in radians (degree*PI/180) to rotate frames (default: -1 -no limit) - -@item crop -How to deal with borders that may be visible due to movement -compensation. Available values are: - -@table @samp -@item keep -keep image information from previous frame (default) -@item black -fill the border black -@end table - -@item invert -@table @samp -@item 0 -keep transforms normal (default) -@item 1 -invert transforms -@end table - -@item relative -consider transforms as -@table @samp -@item 0 -absolute -@item 1 -relative to previous frame (default) -@end table - -@item zoom -percentage to zoom (default: 0) -@table @samp -@item >0 -zoom in -@item <0 -zoom out -@end table - -@item optzoom -set optimal zooming to avoid borders -@table @samp -@item 0 -disabled -@item 1 -optimal static zoom value is determined (only very strong movements will lead to visible borders) (default) -@item 2 -optimal adaptive zoom value is determined (no borders will be visible) -@end table -Note that the value given at zoom is added to the one calculated -here. - -@item interpol -type of interpolation - -Available values are: -@table @samp -@item no -no interpolation -@item linear -linear only horizontal -@item bilinear -linear in both directions (default) -@item bicubic -cubic in both directions (slow) -@end table - -@item tripod -virtual tripod mode means that the video is stabilized such that the -camera stays stationary. Use also @code{tripod} option of -@ref{vidstabdetect}. -@table @samp -@item 0 -off (default) -@item 1 -virtual tripod mode: equivalent to @code{relative=0:smoothing=0} -@end table - -@end table - -@subsection Examples - -@itemize -@item -typical call with default default values: - (note the unsharp filter which is always recommended) -@example -ffmpeg -i inp.mpeg -vf vidstabtransform,unsharp=5:5:0.8:3:3:0.4 inp_stabilized.mpeg -@end example - -@item -zoom in a bit more and load transform data from a given file -@example -vidstabtransform=zoom=5:input="mytransforms.trf" -@end example - -@item -smoothen the video even more -@example -vidstabtransform=smoothing=30 -@end example - -@end itemize - -@section vflip - -Flip the input video vertically. - -For example, to vertically flip a video with @command{ffmpeg}: -@example -ffmpeg -i in.avi -vf "vflip" out.avi -@end example - -@section vignette - -Make or reverse a natural vignetting effect. - -The filter accepts the following options: - -@table @option -@item angle, a -Set lens angle expression as a number of radians. - -The value is clipped in the @code{[0,PI/2]} range. - -Default value: @code{"PI/5"} - -@item x0 -@item y0 -Set center coordinates expressions. Respectively @code{"w/2"} and @code{"h/2"} -by default. - -@item mode -Set forward/backward mode. - -Available modes are: -@table @samp -@item forward -The larger the distance from the central point, the darker the image becomes. - -@item backward -The larger the distance from the central point, the brighter the image becomes. -This can be used to reverse a vignette effect, though there is no automatic -detection to extract the lens @option{angle} and other settings (yet). It can -also be used to create a burning effect. -@end table - -Default value is @samp{forward}. - -@item eval -Set evaluation mode for the expressions (@option{angle}, @option{x0}, @option{y0}). - -It accepts the following values: -@table @samp -@item init -Evaluate expressions only once during the filter initialization. - -@item frame -Evaluate expressions for each incoming frame. This is way slower than the -@samp{init} mode since it requires all the scalers to be re-computed, but it -allows advanced dynamic expressions. -@end table - -Default value is @samp{init}. - -@item dither -Set dithering to reduce the circular banding effects. Default is @code{1} -(enabled). - -@item aspect -Set vignette aspect. This setting allows to adjust the shape of the vignette. -Setting this value to the SAR of the input will make a rectangular vignetting -following the dimensions of the video. - -Default is @code{1/1}. -@end table - -@subsection Expressions - -The @option{alpha}, @option{x0} and @option{y0} expressions can contain the -following parameters. - -@table @option -@item w -@item h -input width and height - -@item n -the number of input frame, starting from 0 - -@item pts -the PTS (Presentation TimeStamp) time of the filtered video frame, expressed in -@var{TB} units, NAN if undefined - -@item r -frame rate of the input video, NAN if the input frame rate is unknown - -@item t -the PTS (Presentation TimeStamp) of the filtered video frame, -expressed in seconds, NAN if undefined - -@item tb -time base of the input video -@end table - - -@subsection Examples - -@itemize -@item -Apply simple strong vignetting effect: -@example -vignette=PI/4 -@end example - -@item -Make a flickering vignetting: -@example -vignette='PI/4+random(1)*PI/50':eval=frame -@end example - -@end itemize - -@section w3fdif - -Deinterlace the input video ("w3fdif" stands for "Weston 3 Field -Deinterlacing Filter"). - -Based on the process described by Martin Weston for BBC R&D, and -implemented based on the de-interlace algorithm written by Jim -Easterbrook for BBC R&D, the Weston 3 field deinterlacing filter -uses filter coefficients calculated by BBC R&D. - -There are two sets of filter coefficients, so called "simple": -and "complex". Which set of filter coefficients is used can -be set by passing an optional parameter: - -@table @option -@item filter -Set the interlacing filter coefficients. Accepts one of the following values: - -@table @samp -@item simple -Simple filter coefficient set. -@item complex -More-complex filter coefficient set. -@end table -Default value is @samp{complex}. - -@item deint -Specify which frames to deinterlace. Accept one of the following values: - -@table @samp -@item all -Deinterlace all frames, -@item interlaced -Only deinterlace frames marked as interlaced. -@end table - -Default value is @samp{all}. -@end table - -@anchor{yadif} -@section yadif - -Deinterlace the input video ("yadif" means "yet another deinterlacing -filter"). - -This filter accepts the following options: - - -@table @option - -@item mode -The interlacing mode to adopt, accepts 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 -The picture field parity assumed for the input interlaced video, accepts 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}. - -This source accepts the following options: - -@table @option - -@item video_size -Specify the size (width and height) of the buffered video frames. For the -syntax of this option, check the "Video size" section in the ffmpeg-utils -manual. - -@item width -Input video width. - -@item height -Input video height. - -@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 frame_rate -Specify the frame rate expected for the video stream. - -@item pixel_aspect, sar -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=width=320:height=240:pix_fmt=yuv410p:time_base=1/24:sar=1 -@end example - -will instruct the source to accept video frames with size 320x240 and -with format "yuv410p", assuming 1/24 as the timestamps timebase and -square pixels (1:1 sample aspect ratio). -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 the following options: - -@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. For the syntax of this option, check -the "Video size" section in the ffmpeg-utils manual. - -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 the following options: - -@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. For the syntax of this option, check the "Video -size" section in the ffmpeg-utils manual. 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 the following options: - -@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}. - -This source accepts the following options: - -@table @option - -@item size -The size of the video to generate. For the syntax of this option, check the -"Video size" section in the ffmpeg-utils manual. - -@item framerate -Framerate of the generated video, may be a string of the form -@var{num}/@var{den} or a frame rate abbreviation. - -@item filter_name -The name to the frei0r source to load. For more information regarding frei0r and -how to set the parameters read the section @ref{frei0r} in the description of -the video filters. - -@item filter_params -A '|'-separated list of parameters to pass to the frei0r source. - -@end table - -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=size=200x200:framerate=10:filter_name=partik0l:filter_params=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 the following options: - -@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. For the syntax of this option, check the -"Video size" section in the ffmpeg-utils manual. - -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. - -For the syntax of these 3 color options, check the "Color" section in the -ffmpeg-utils manual. -@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 - -@anchor{color} -@anchor{haldclutsrc} -@anchor{nullsrc} -@anchor{rgbtestsrc} -@anchor{smptebars} -@anchor{smptehdbars} -@anchor{testsrc} -@section color, haldclutsrc, nullsrc, rgbtestsrc, smptebars, smptehdbars, testsrc - -The @code{color} source provides an uniformly colored input. - -The @code{haldclutsrc} source provides an identity Hald CLUT. See also -@ref{haldclut} filter. - -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{smptehdbars} source generates a color bars pattern, based on -the SMPTE RP 219-2002. - -The @code{testsrc} source generates a test video pattern, showing a -color pattern, a scrolling gradient and a timestamp. This is mainly -intended for testing purposes. - -The sources accept the following options: - -@table @option - -@item color, c -Specify the color of the source, only available in the @code{color} -source. For the syntax of this option, check the "Color" section in the -ffmpeg-utils manual. - -@item level -Specify the level of the Hald CLUT, only available in the @code{haldclutsrc} -source. A level of @code{N} generates a picture of @code{N*N*N} by @code{N*N*N} -pixels to be used as identity matrix for 3D lookup tables. Each component is -coded on a @code{1/(N*N)} scale. - -@item size, s -Specify the size of the sourced video. For the syntax of this option, check the -"Video size" section in the ffmpeg-utils manual. The default value is -"320x240". - -This option is not available with the @code{haldclutsrc} filter. - -@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 available 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 - -@subsection Commands - -The @code{color} source supports the following commands: - -@table @option -@item c, color -Set the color of the created image. Accepts the same syntax of the -corresponding @option{color} option. -@end table - -@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} -or the options system. - -It accepts a pointer to an AVBufferSinkContext structure, which -defines the incoming buffers' formats, to be passed as the opaque -parameter to @code{avfilter_init_filter} for initialization. - -@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 avectorscope - -Convert input audio to a video output, representing the audio vector -scope. - -The filter is used to measure the difference between channels of stereo -audio stream. A monoaural signal, consisting of identical left and right -signal, results in straight vertical line. Any stereo separation is visible -as a deviation from this line, creating a Lissajous figure. -If the straight (or deviation from it) but horizontal line appears this -indicates that the left and right channels are out of phase. - -The filter accepts the following options: - -@table @option -@item mode, m -Set the vectorscope mode. - -Available values are: -@table @samp -@item lissajous -Lissajous rotated by 45 degrees. - -@item lissajous_xy -Same as above but not rotated. -@end table - -Default value is @samp{lissajous}. - -@item size, s -Set the video size for the output. For the syntax of this option, check the "Video size" -section in the ffmpeg-utils manual. Default value is @code{400x400}. - -@item rate, r -Set the output frame rate. Default value is @code{25}. - -@item rc -@item gc -@item bc -Specify the red, green and blue contrast. Default values are @code{40}, @code{160} and @code{80}. -Allowed range is @code{[0, 255]}. - -@item rf -@item gf -@item bf -Specify the red, green and blue fade. Default values are @code{15}, @code{10} and @code{5}. -Allowed range is @code{[0, 255]}. - -@item zoom -Set the zoom factor. Default value is @code{1}. Allowed range is @code{[1, 10]}. -@end table - -@subsection Examples - -@itemize -@item -Complete example using @command{ffplay}: -@example -ffplay -f lavfi 'amovie=input.mp3, asplit [a][out1]; - [a] avectorscope=zoom=1.3:rc=2:gc=200:bc=10:rf=1:gf=8:bf=7 [out0]' -@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 options: - -@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 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 options: - -@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. For the syntax of this -option, check the "Video size" section in the ffmpeg-utils manual. 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 interleave, ainterleave - -Temporally interleave frames from several inputs. - -@code{interleave} works with video inputs, @code{ainterleave} with audio. - -These filters read frames from several inputs and send the oldest -queued frame to the output. - -Input streams must have a well defined, monotonically increasing frame -timestamp values. - -In order to submit one frame to output, these filters need to enqueue -at least one frame for each input, so they cannot work in case one -input is not yet terminated and will not receive incoming frames. - -For example consider the case when one input is a @code{select} filter -which always drop input frames. The @code{interleave} filter will keep -reading from that input, but it will never be able to send new frames -to output until the input will send an end-of-stream signal. - -Also, depending on inputs synchronization, the filters will drop -frames in case one input receives more frames than the other ones, and -the queue is already filled. - -These filters accept the following options: - -@table @option -@item nb_inputs, n -Set the number of different inputs, it is 2 by default. -@end table - -@subsection Examples - -@itemize -@item -Interleave frames belonging to different streams using @command{ffmpeg}: -@example -ffmpeg -i bambi.avi -i pr0n.mkv -filter_complex "[0:v][1:v] interleave" out.avi -@end example - -@item -Add flickering blur effect: -@example -select='if(gt(random(0), 0.2), 1, 2)':n=2 [tmp], boxblur=2:2, [tmp] interleave -@end example -@end itemize - -@section perms, aperms - -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 the following options: - -@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 - -@item seed -Set the seed for the @var{random} mode, must be an integer included between -@code{0} and @code{UINT32_MAX}. If not specified, or if explicitly set to -@code{-1}, the filter will try to use a good random seed on a best effort -basis. -@end table - -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 select, aselect - -Select frames to pass in output. - -This filter accepts the following options: - -@table @option - -@item expr, e -Set expression, which is evaluated for each input frame. - -If the expression is evaluated to zero, the frame is discarded. - -If the evaluation result is negative or NaN, the frame is sent to the -first output; otherwise it is sent to the output with index -@code{ceil(val)-1}, assuming that the input index starts from 0. - -For example a value of @code{1.2} corresponds to the output with index -@code{ceil(1.2)-1 = 2-1 = 1}, that is the second output. - -@item outputs, n -Set the number of outputs. The output to which to send the selected -frame is based on the result of the evaluation. Default value is 1. -@end table - -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=between(t\,10\,20) -@end example - -@item -Select only I frames contained in the 10-20 time interval: -@example -select=between(t\,10\,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. - -@item -Send even and odd frames to separate outputs, and compose them: -@example -select=n=2:e='mod(n, 2)+1' [odd][even]; [odd] pad=h=2*ih [tmp]; [tmp][even] overlay=y=h -@end example -@end itemize - -@section sendcmd, asendcmd - -Send commands to filters in the filtergraph. - -These filters read commands to be sent to other filters in the -filtergraph. - -@code{sendcmd} must be inserted between two video filters, -@code{asendcmd} must be inserted between two audio 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 s 0, - [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor', - [leave] hue 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(25-t) -@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 setpts, asetpts - -Change the PTS (presentation timestamp) of the input frames. - -@code{setpts} works on video frames, @code{asetpts} on audio frames. - -This filter accepts the following options: - -@table @option - -@item expr -The expression which is evaluated for each frame to construct its timestamp. - -@end table - -The expression is evaluated through the eval API and 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 for video or the number of consumed samples, -not including the current frame for audio, starting from 0. - -@item NB_CONSUMED_SAMPLES -the number of consumed samples, not including the current frame (only -audio) - -@item NB_SAMPLES, S -the number of samples in the current frame (only audio) - -@item SAMPLE_RATE, SR -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 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 - -@item TB -timebase of the input timestamps - -@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 - -@item -Generate timestamps by counting samples: -@example -asetpts=N/SR/TB -@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 the following options: - -@table @option - -@item expr, tb -The expression which is evaluated into the output timebase. - -@end table - -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=expr=1/25 -@end example - -@item -Set the timebase to 1/10: -@example -settb=expr=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 showspectrum - -Convert input audio to a video output, representing the audio frequency -spectrum. - -The filter accepts the following options: - -@table @option -@item size, s -Specify the video size for the output. For the syntax of this option, check -the "Video size" section in the ffmpeg-utils manual. 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}. - -@item win_func -Set window function. - -It accepts the following values: -@table @samp -@item none -No samples pre-processing (do not expect this to be faster) -@item hann -Hann window -@item hamming -Hamming window -@item blackman -Blackman window -@end table - -Default value is @code{hann}. -@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 options: - -@table @option -@item size, s -Specify the video size for the output. For the syntax of this option, check -the "Video size" section in the ffmpeg-utils manual. Default value -is "600x240". - -@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". - -@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 -frame rate of 30 frames per second: -@example -aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1] -@end example -@end itemize - -@section split, asplit - -Split input into several identical outputs. - -@code{asplit} works with audio input, @code{split} with video. - -The filter accepts a single parameter which specifies the number of outputs. If -unspecified, it defaults to 2. - -@subsection Examples - -@itemize -@item -Create two separate outputs from the same input: -@example -[in] split [out0][out1] -@end example - -@item -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 - -@item -Create two separate outputs from the same input, one cropped and -one padded: -@example -[in] split [splitout1][splitout2]; -[splitout1] crop=100:100:0:0 [cropout]; -[splitout2] pad=200:200:100:100 [padout]; -@end example - -@item -Create 5 copies of the input audio with @command{ffmpeg}: -@example -ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT -@end example -@end itemize - -@section zmq, azmq - -Receive commands sent through a libzmq client, and forward them to -filters in the filtergraph. - -@code{zmq} and @code{azmq} work as a pass-through filters. @code{zmq} -must be inserted between two video filters, @code{azmq} between two -audio filters. - -To enable these filters you need to install the libzmq library and -headers and configure FFmpeg with @code{--enable-libzmq}. - -For more information about libzmq see: -@url{http://www.zeromq.org/} - -The @code{zmq} and @code{azmq} filters work as a libzmq server, which -receives messages sent through a network interface defined by the -@option{bind_address} option. - -The received message must be in the form: -@example -@var{TARGET} @var{COMMAND} [@var{ARG}] -@end example - -@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 argument list for the -given @var{COMMAND}. - -Upon reception, the message is processed and the corresponding command -is injected into the filtergraph. Depending on the result, the filter -will send a reply to the client, adopting the format: -@example -@var{ERROR_CODE} @var{ERROR_REASON} -@var{MESSAGE} -@end example - -@var{MESSAGE} is optional. - -@subsection Examples - -Look at @file{tools/zmqsend} for an example of a zmq client which can -be used to send commands processed by these filters. - -Consider the following filtergraph generated by @command{ffplay} -@example -ffplay -dumpgraph 1 -f lavfi " -color=s=100x100:c=red [l]; -color=s=100x100:c=blue [r]; -nullsrc=s=200x100, zmq [bg]; -[bg][l] overlay [bg+l]; -[bg+l][r] overlay=x=100 " -@end example - -To change the color of the left side of the video, the following -command can be used: -@example -echo Parsed_color_0 c yellow | tools/zmqsend -@end example - -To change the right side: -@example -echo Parsed_color_1 c pink | tools/zmqsend -@end example - -@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. - -This filter accepts the following options: - -@table @option -@item filename -The name of the resource to read (not necessarily a file but also a device or a -stream accessed through some protocol). - -@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 [over]; -[in] setpts=PTS-STARTPTS [main]; -[main][over] 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 [over]; -[in] setpts=PTS-STARTPTS [main]; -[main][over] 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 |