+@chapter Filtering Introduction
+@c man begin FILTERING INTRODUCTION
+
+Filtering in FFmpeg is enabled through the libavfilter library.
+
+Libavfilter is the filtering API of FFmpeg. It is the substitute of
+the now deprecated 'vhooks' and started as a Google Summer of Code
+project.
+
+Audio filtering integration into the main FFmpeg repository is a work in
+progress, so audio API and ABI should not be considered stable yet.
+
+In libavfilter, it is possible for filters to have multiple inputs and
+multiple outputs.
+To illustrate the sorts of things that are possible, we can
+use a complex filter graph. For example, the following one:
+
+@example
+input --> split --> fifo -----------------------> overlay --> output
+ | ^
+ | |
+ +------> fifo --> crop --> vflip --------+
+@end example
+
+splits the stream in two streams, sends one stream through the crop filter
+and the vflip filter before merging it back with the other stream by
+overlaying it on top. You can use the following command to achieve this:
+
+@example
+ffmpeg -i input -vf "[in] split [T1], fifo, [T2] overlay=0:H/2 [out]; [T1] fifo, crop=iw:ih/2:0:ih/2, vflip [T2]" output
+@end example
+
+The result will be that in output the top half of the video is mirrored
+onto the bottom half.
+
+Filters are loaded using the @var{-vf} or @var{-af} option passed to
+@command{ffmpeg} or to @command{ffplay}. Filters in the same linear
+chain are separated by commas. In our example, @var{split, fifo,
+overlay} are in one linear chain, and @var{fifo, crop, vflip} are in
+another. The points where the linear chains join are labeled by names
+enclosed in square brackets. In our example, that is @var{[T1]} and
+@var{[T2]}. The special labels @var{[in]} and @var{[out]} are the points
+where video is input and output.
+
+Some filters take in input a list of parameters: they are specified
+after the filter name and an equal sign, and are separated from each other
+by a colon.
+
+There exist so-called @var{source filters} that do not have an
+audio/video input, and @var{sink filters} that will not have audio/video
+output.
+
+@c man end FILTERING INTRODUCTION
+
+@chapter graph2dot
+@c man begin GRAPH2DOT
+
+The @file{graph2dot} program included in the FFmpeg @file{tools}
+directory can be used to parse a filter graph description and issue a
+corresponding textual representation in the dot language.
+
+Invoke the command:
+@example
+graph2dot -h
+@end example
+
+to see how to use @file{graph2dot}.
+
+You can then pass the dot description to the @file{dot} program (from
+the graphviz suite of programs) and obtain a graphical representation
+of the filter graph.
+
+For example the sequence of commands:
+@example
+echo @var{GRAPH_DESCRIPTION} | \
+tools/graph2dot -o graph.tmp && \
+dot -Tpng graph.tmp -o graph.png && \
+display graph.png
+@end example
+
+can be used to create and display an image representing the graph
+described by the @var{GRAPH_DESCRIPTION} string. Note that this string must be
+a complete self-contained graph, with its inputs and outputs explicitly defined.
+For example if your command line is of the form:
+@example
+ffmpeg -i infile -vf scale=640:360 outfile
+@end example
+your @var{GRAPH_DESCRIPTION} string will need to be of the form:
+@example
+nullsrc,scale=640:360,nullsink
+@end example
+you may also need to set the @var{nullsrc} parameters and add a @var{format}
+filter in order to simulate a specific input file.
+
+@c man end GRAPH2DOT
+
@chapter Filtergraph description
@c man begin FILTERGRAPH DESCRIPTION
A filtergraph can be represented using a textual representation, which is
recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
-options in @command{avconv} and @option{-vf} in @command{avplay}, and by the
+options in @command{ffmpeg} and @option{-vf} in @command{ffplay}, and by the
@code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
@file{libavfilter/avfiltergraph.h}.
@chapter Audio Filters
@c man begin AUDIO FILTERS
-When you configure your Libav build, you can disable any of the
-existing filters using --disable-filters.
+When you configure your FFmpeg build, you can disable any of the
+existing filters using @code{--disable-filters}.
The configure output will show the audio filters included in your
build.
Below is a description of the currently available audio filters.
+@section aconvert
+
+Convert the input audio format to the specified formats.
+
+The filter accepts a string of the form:
+"@var{sample_format}:@var{channel_layout}".
+
+@var{sample_format} specifies the sample format, and can be a string or the
+corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
+suffix for a planar sample format.
+
+@var{channel_layout} specifies the channel layout, and can be a string
+or the corresponding number value defined in @file{libavutil/audioconvert.h}.
+
+The special parameter "auto", signifies that the filter will
+automatically select the output format depending on the output filter.
+
+Some examples follow.
+
+@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 aformat
Convert the input audio to one of the specified formats. The framework will
aformat=sample_fmts\=u8\,s16:channel_layouts\=stereo
@end example
+@section amerge
+
+Merge two or more audio streams into a single multi-channel stream.
+
+The filter accepts the following named options:
+
+@table @option
+
+@item inputs
+Set the number of inputs. Default is 2.
+
+@end table
+
+If the channel layouts of the inputs are disjoint, and therefore compatible,
+the channel layout of the output will be set accordingly and the channels
+will be reordered as necessary. If the channel layouts of the inputs are not
+disjoint, the output will have all the channels of the first input then all
+the channels of the second input, in that order, and the channel layout of
+the output will be the default value corresponding to the total number of
+channels.
+
+For example, if the first input is in 2.1 (FL+FR+LF) and the second input
+is FC+BL+BR, then the output will be in 5.1, with the channels in the
+following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
+first input, b1 is the first channel of the second input).
+
+On the other hand, if both input are in stereo, the output channels will be
+in the default order: a1, a2, b1, b2, and the channel layout will be
+arbitrarily set to 4.0, which may or may not be the expected value.
+
+All inputs must have the same sample rate, and format.
+
+If inputs do not have the same duration, the output will stop with the
+shortest.
+
+Example: merge two mono files into a stereo stream:
+@example
+amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
+@end example
+
+Example: multiple merges:
+@example
+ffmpeg -f lavfi -i "
+amovie=input.mkv:si=0 [a0];
+amovie=input.mkv:si=1 [a1];
+amovie=input.mkv:si=2 [a2];
+amovie=input.mkv:si=3 [a3];
+amovie=input.mkv:si=4 [a4];
+amovie=input.mkv:si=5 [a5];
+[a0][a1][a2][a3][a4][a5] amerge=inputs=6" -c:a pcm_s16le output.mkv
+@end example
+
@section amix
Mixes multiple audio inputs into a single output.
For example
@example
-avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
+ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
@end example
will mix 3 input audio streams to a single output with the same duration as the
first input and a dropout transition time of 3 seconds.
Pass the audio source unchanged to the output.
+@section aresample
+
+Resample the input audio to the specified sample rate.
+
+The filter accepts exactly one parameter, the output sample rate. If not
+specified then the filter will automatically convert between its input
+and output sample rates.
+
+For example, to resample the input audio to 44100Hz:
+@example
+aresample=44100
+@end example
+
+@section asetnsamples
+
+Set the number of samples per each output audio frame.
+
+The last output packet may contain a different number of samples, as
+the filter will flush all the remaining samples when the input audio
+signal its end.
+
+The filter accepts parameters as a list of @var{key}=@var{value} pairs,
+separated by ":".
+
+@table @option
+
+@item nb_out_samples, n
+Set the number of frames per each output audio frame. The number is
+intended as the number of samples @emph{per each channel}.
+Default value is 1024.
+
+@item pad, p
+If set to 1, the filter will pad the last audio frame with zeroes, so
+that the last frame will contain the same number of samples as the
+previous ones. Default value is 1.
+@end table
+
+For example, to set the number of per-frame samples to 1234 and
+disable padding for the last frame, use:
+@example
+asetnsamples=n=1234:p=0
+@end example
+
+@section ashowinfo
+
+Show a line containing various information for each input audio frame.
+The input audio is not modified.
+
+The shown line contains a sequence of key/value pairs of the form
+@var{key}:@var{value}.
+
+A description of each shown parameter follows:
+
+@table @option
+@item n
+sequential number of the input frame, starting from 0
+
+@item pts
+presentation TimeStamp of the input frame, expressed as a number of
+time base units. The time base unit depends on the filter input pad, and
+is usually 1/@var{sample_rate}.
+
+@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 audio)
+
+@item fmt
+sample format name
+
+@item chlayout
+channel layout description
+
+@item nb_samples
+number of samples (per each channel) contained in the filtered frame
+
+@item rate
+sample rate for the audio frame
+
+@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) for each input frame plane,
+expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3} @var{c4} @var{c5}
+@var{c6} @var{c7}]"
+@end table
+
@section asplit
Split input audio into several identical outputs.
The filter accepts a single parameter which specifies the number of outputs. If
unspecified, it defaults to 2.
-For example
+For example:
+@example
+[in] asplit [out0][out1]
+@end example
+
+will create two separate outputs from the same input.
+
+To create 3 or more outputs, you need to specify the number of
+outputs, like in:
+@example
+[in] asplit=3 [out0][out1][out2]
+@end example
+
@example
-avconv -i INPUT -filter_complex asplit=5 OUTPUT
+ffmpeg -i INPUT -filter_complex asplit=5 OUTPUT
@end example
will create 5 copies of the input audio.
+
+@section astreamsync
+
+Forward two audio streams and control the order the buffers are forwarded.
+
+The argument to the filter is an expression deciding which stream should be
+forwarded next: if the result is negative, the first stream is forwarded; if
+the result is positive or zero, the second stream is forwarded. It can use
+the following variables:
+
+@table @var
+@item b1 b2
+number of buffers forwarded so far on each stream
+@item s1 s2
+number of samples forwarded so far on each stream
+@item t1 t2
+current timestamp of each stream
+@end table
+
+The default value is @code{t1-t2}, which means to always forward the stream
+that has a smaller timestamp.
+
+Example: stress-test @code{amerge} by randomly sending buffers on the wrong
+input, while avoiding too much of a desynchronization:
+@example
+amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
+[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
+[a2] [b2] amerge
+@end example
+
+@section atempo
+
+Adjust audio tempo.
+
+The filter accepts exactly one parameter, the audio tempo. If not
+specified then the filter will assume nominal 1.0 tempo. Tempo must
+be in the [0.5, 2.0] range.
+
+For example, to slow down audio to 80% tempo:
+@example
+atempo=0.8
+@end example
+
+For example, to speed up audio to 125% tempo:
+@example
+atempo=1.25
+@end example
+
+@section earwax
+
+Make audio easier to listen to on headphones.
+
+This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
+so that when listened to on headphones the stereo image is moved from
+inside your head (standard for headphones) to outside and in front of
+the listener (standard for speakers).
+
+Ported from SoX.
+
+@section pan
+
+Mix channels with specific gain levels. The filter accepts the output
+channel layout followed by a set of channels definitions.
+
+This filter is also designed to remap efficiently the channels of an audio
+stream.
+
+The filter accepts parameters of the form:
+"@var{l}:@var{outdef}:@var{outdef}:..."
+
+@table @option
+@item l
+output channel layout or number of channels
+
+@item outdef
+output channel specification, of the form:
+"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
+
+@item out_name
+output channel to define, either a channel name (FL, FR, etc.) or a channel
+number (c0, c1, etc.)
+
+@item gain
+multiplicative coefficient for the channel, 1 leaving the volume unchanged
+
+@item in_name
+input channel to use, see out_name for details; it is not possible to mix
+named and numbered input channels
+@end table
+
+If the `=' in a channel specification is replaced by `<', then the gains for
+that specification will be renormalized so that the total is 1, thus
+avoiding clipping noise.
+
+@subsection Mixing examples
+
+For example, if you want to down-mix from stereo to mono, but with a bigger
+factor for the left channel:
+@example
+pan=1:c0=0.9*c0+0.1*c1
+@end example
+
+A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
+7-channels surround:
+@example
+pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
+@end example
+
+Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
+that should be preferred (see "-ac" option) unless you have very specific
+needs.
+
+@subsection Remapping examples
+
+The channel remapping will be effective if, and only if:
+
+@itemize
+@item gain coefficients are zeroes or ones,
+@item only one input per channel output,
+@end itemize
+
+If all these conditions are satisfied, the filter will notify the user ("Pure
+channel mapping detected"), and use an optimized and lossless method to do the
+remapping.
+
+For example, if you have a 5.1 source and want a stereo audio stream by
+dropping the extra channels:
+@example
+pan="stereo: c0=FL : c1=FR"
+@end example
+
+Given the same source, you can also switch front left and front right channels
+and keep the input channel layout:
+@example
+pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
+@end example
+
+If the input is a stereo audio stream, you can mute the front left channel (and
+still keep the stereo channel layout) with:
+@example
+pan="stereo:c1=c1"
+@end example
+
+Still with a stereo audio stream input, you can copy the right channel in both
+front left and right:
+@example
+pan="stereo: c0=FR : c1=FR"
+@end example
+
+@section silencedetect
+
+Detect silence in an audio stream.
+
+This filter logs a message when it detects that the input audio volume is less
+or equal to a noise tolerance value for a duration greater or equal to the
+minimum detected noise duration.
+
+The printed times and duration are expressed in seconds.
+
+@table @option
+@item duration, d
+Set silence duration until notification (default is 2 seconds).
+
+@item noise, n
+Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
+specified value) or amplitude ratio. Default is -60dB, or 0.001.
+@end table
+
+Detect 5 seconds of silence with -50dB noise tolerance:
+@example
+silencedetect=n=-50dB:d=5
+@end example
+
+Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
+tolerance in @file{silence.mp3}:
+@example
+ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
+@end example
+
+@section volume
+
+Adjust the input audio volume.
+
+The filter accepts exactly one parameter @var{vol}, which expresses
+how the audio volume will be increased or decreased.
+
+Output values are clipped to the maximum value.
+
+If @var{vol} is expressed as a decimal number, the output audio
+volume is given by the relation:
+@example
+@var{output_volume} = @var{vol} * @var{input_volume}
+@end example
+
+If @var{vol} is expressed as a decimal number followed by the string
+"dB", the value represents the requested change in decibels of the
+input audio power, and the output audio volume is given by the
+relation:
+@example
+@var{output_volume} = 10^(@var{vol}/20) * @var{input_volume}
+@end example
+
+Otherwise @var{vol} is considered an expression and its evaluated
+value is used for computing the output audio volume according to the
+first relation.
+
+Default value for @var{vol} is 1.0.
+
+@subsection Examples
+
+@itemize
+@item
+Half the input audio volume:
+@example
+volume=0.5
+@end example
+
+The above example is equivalent to:
+@example
+volume=1/2
+@end example
+
+@item
+Decrease input audio power by 12 decibels:
+@example
+volume=-12dB
+@end example
+@end itemize
+
+@section volumedetect
+
+Detect the volume of the input video.
+
+The filter has no parameters. The input is not modified. Statistics about
+the volume will be printed in the log when the input stream end is reached.
+
+In particular it will show the mean volume (root mean square), maximum
+volume (on a per-sample basis), and the beginning of an histogram of the
+registered volume values (from the maximum value to a cumulated 1/1000 of
+the samples).
+
+All volumes are in decibels relative to the maximum PCM value.
+
+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.
+
@section asyncts
Synchronize audio data with timestamps by squeezing/stretching it and/or
dropping samples/adding silence when needed.
For example, assuming a stereo input MP3 file
@example
-avconv -i in.mp3 -filter_complex channelsplit out.mkv
+ffmpeg -i in.mp3 -filter_complex channelsplit out.mkv
@end example
will create an output Matroska file with two audio streams, one containing only
the left channel and the other the right channel.
To split a 5.1 WAV file into per-channel files
@example
-avconv -i in.wav -filter_complex
+ffmpeg -i in.wav -filter_complex
'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
-map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
For example, assuming a 5.1+downmix input MOV file
@example
-avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
+ffmpeg -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
@end example
will create an output WAV file tagged as stereo from the downmix channels of
the input.
To fix a 5.1 WAV improperly encoded in AAC's native channel order
@example
-avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
+ffmpeg -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
@end example
@section join
E.g. to join 3 inputs (with properly set channel layouts)
@example
-avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
+ffmpeg -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
@end example
To build a 5.1 output from 6 single-channel streams:
@example
-avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
+ffmpeg -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
'join=inputs=6:channel_layout=5.1:map=0.0-FL\,1.0-FR\,2.0-FC\,3.0-SL\,4.0-SR\,5.0-LFE'
out
@end example
@section resample
Convert the audio sample format, sample rate and channel layout. This filter is
-not meant to be used directly, it is inserted automatically by libavfilter
-whenever conversion is needed. Use the @var{aformat} filter to force a specific
-conversion.
+not meant to be used directly.
@c man end AUDIO FILTERS
Below is a description of the currently available audio sources.
-@section anullsrc
+@section abuffer
-Null audio source, never return audio frames. It is mainly useful as a
-template and to be employed in analysis / debugging tools.
+Buffer audio frames, and make them available to the filter chain.
-It accepts as optional parameter a string of the form
-@var{sample_rate}:@var{channel_layout}.
+This source is mainly intended for a programmatic use, in particular
+through the interface defined in @file{libavfilter/asrc_abuffer.h}.
-@var{sample_rate} specify the sample rate, and defaults to 44100.
+It accepts the following mandatory parameters:
+@var{sample_rate}:@var{sample_fmt}:@var{channel_layout}
-@var{channel_layout} specify the channel layout, and can be either an
-integer or a string representing a channel layout. The default value
-of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
+@table @option
-Check the channel_layout_map definition in
-@file{libavcodec/audioconvert.c} for the mapping between strings and
-channel layout values.
+@item sample_rate
+The sample rate of the incoming audio buffers.
-Follow some examples:
+@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/audioconvert.c} or its corresponding integer representation
+from the AV_CH_LAYOUT_* macros in @file{libavutil/audioconvert.h}
+
+@end table
+
+For example:
+@example
+abuffer=44100:s16p:stereo
+@end example
+
+will instruct the source to accept planar 16bit signed stereo at 44100Hz.
+Since the sample format with name "s16p" corresponds to the number
+6 and the "stereo" channel layout corresponds to the value 0x3, this is
+equivalent to:
+@example
+abuffer=44100:6:0x3
+@end example
+
+@section aevalsrc
+
+Generate an audio signal specified by an expression.
+
+This source accepts in input one or more expressions (one for each
+channel), which are evaluated and used to generate a corresponding
+audio signal.
+
+It accepts the syntax: @var{exprs}[::@var{options}].
+@var{exprs} is a list of expressions separated by ":", one for each
+separate channel. In case the @var{channel_layout} is not
+specified, the selected channel layout depends on the number of
+provided expressions.
+
+@var{options} is an optional sequence of @var{key}=@var{value} pairs,
+separated by ":".
+
+The description of the accepted options follows.
+
+@table @option
+
+@item channel_layout, c
+Set the channel layout. The number of channels in the specified layout
+must be equal to the number of specified expressions.
+
+@item duration, d
+Set the minimum duration of the sourced audio. See the function
+@code{av_parse_time()} for the accepted format.
+Note that the resulting duration may be greater than the specified
+duration, as the generated audio is always cut at the end of a
+complete frame.
+
+If not specified, or the expressed duration is negative, the audio is
+supposed to be generated forever.
+
+@item nb_samples, n
+Set the number of samples per channel per each output frame,
+default to 1024.
+
+@item sample_rate, s
+Specify the sample rate, default to 44100.
+@end table
+
+Each expression in @var{exprs} can contain the following constants:
+
+@table @option
+@item n
+number of the evaluated sample, starting from 0
+
+@item t
+time of the evaluated sample expressed in seconds, starting from 0
+
+@item s
+sample rate
+
+@end table
+
+@subsection Examples
+
+@itemize
+
+@item
+Generate silence:
+@example
+aevalsrc=0
+@end example
+
+@item
+
+Generate a sin signal with frequency of 440 Hz, set sample rate to
+8000 Hz:
+@example
+aevalsrc="sin(440*2*PI*t)::s=8000"
+@end example
+
+@item
+Generate a two channels signal, specify the channel layout (Front
+Center + Back Center) explicitly:
+@example
+aevalsrc="sin(420*2*PI*t):cos(430*2*PI*t)::c=FC|BC"
+@end example
+
+@item
+Generate white noise:
+@example
+aevalsrc="-2+random(0)"
+@end example
+
+@item
+Generate an amplitude modulated signal:
+@example
+aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
+@end example
+
+@item
+Generate 2.5 Hz binaural beats on a 360 Hz carrier:
+@example
+aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) : 0.1*sin(2*PI*(360+2.5/2)*t)"
+@end example
+
+@end itemize
+
+@section anullsrc
+
+Null audio source, return unprocessed audio frames. It is mainly useful
+as a template and to be employed in analysis / debugging tools, or as
+the source for filters which ignore the input data (for example the sox
+synth filter).
+
+It accepts an optional sequence of @var{key}=@var{value} pairs,
+separated by ":".
+
+The description of the accepted options follows.
+
+@table @option
+
+@item sample_rate, s
+Specify the sample rate, and defaults to 44100.
+
+@item channel_layout, cl
+
+Specify the channel layout, and can be either an integer or a string
+representing a channel layout. The default value of @var{channel_layout}
+is "stereo".
+
+Check the channel_layout_map definition in
+@file{libavcodec/audioconvert.c} for the mapping between strings and
+channel layout values.
+
+@item nb_samples, n
+Set the number of samples per requested frames.
+
+@end table
+
+Follow some examples:
@example
-# set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
-anullsrc=48000:4
+# set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
+anullsrc=r=48000:cl=4
# same as
-anullsrc=48000:mono
+anullsrc=r=48000:cl=mono
@end example
@section abuffer
All the parameters need to be explicitly defined.
+@section flite
+
+Synthesize a voice utterance using the libflite library.
+
+To enable compilation of this filter you need to configure FFmpeg with
+@code{--enable-libflite}.
+
+Note that the flite library is not thread-safe.
+
+The source accepts parameters as a list of @var{key}=@var{value} pairs,
+separated by ":".
+
+The description of the accepted parameters follows.
+
+@table @option
+
+@item list_voices
+If set to 1, list the names of the available voices and exit
+immediately. Default value is 0.
+
+@item nb_samples, n
+Set the maximum number of samples per frame. Default value is 512.
+
+@item textfile
+Set the filename containing the text to speak.
+
+@item text
+Set the text to speak.
+
+@item voice, v
+Set the voice to use for the speech synthesis. Default value is
+@code{kal}. See also the @var{list_voices} option.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Read from file @file{speech.txt}, and synthetize the text using the
+standard flite voice:
+@example
+flite=textfile=speech.txt
+@end example
+
+@item
+Read the specified text selecting the @code{slt} voice:
+@example
+flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
+@end example
+
+@item
+Input text to ffmpeg:
+@example
+ffmpeg -f lavfi -i flite=text='So fare thee well, poor devil of a Sub-Sub, whose commentator I am':voice=slt
+@end example
+
+@item
+Make @file{ffplay} speak the specified text, using @code{flite} and
+the @code{lavfi} device:
+@example
+ffplay -f lavfi flite=text='No more be grieved for which that thou hast done.'
+@end example
+@end itemize
+
+For more information about libflite, check:
+@url{http://www.speech.cs.cmu.edu/flite/}
+
@c man end AUDIO SOURCES
@chapter Audio Sinks
Below is a description of the currently available audio sinks.
+@section abuffersink
+
+Buffer audio frames, and make them available to the end of filter chain.
+
+This sink is mainly intended for programmatic use, in particular
+through the interface defined in @file{libavfilter/buffersink.h}.
+
+It requires a pointer to an AVABufferSinkContext structure, which
+defines the incoming buffers' formats, to be passed as the opaque
+parameter to @code{avfilter_init_filter} for initialization.
+
@section anullsink
Null audio sink, do absolutely nothing with the input audio. It is
@chapter Video Filters
@c man begin VIDEO FILTERS
-When you configure your Libav build, you can disable any of the
-existing filters using --disable-filters.
+When you configure your FFmpeg build, you can disable any of the
+existing filters using @code{--disable-filters}.
The configure output will show the 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
+
+Draw ASS (Advanced Substation Alpha) 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 accepts the following named options, expressed as a
+sequence of @var{key}=@var{value} pairs, separated by ":".
+
+@table @option
+@item filename, f
+Set the filename of the ASS file to read. It must be specified.
+
+@item original_size
+Specify the size of the original video, the video for which the ASS file
+was composed. Due to a misdesign in ASS aspect ratio arithmetic, this is
+necessary to correctly scale the fonts if the aspect ratio has been changed.
+@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.ass} on top of the input
+video, use the command:
+@example
+ass=sub.ass
+@end example
+
+which is equivalent to:
+@example
+ass=filename=sub.ass
+@end example
+
+@section bbox
+
+Compute the bounding box for the non-black pixels in the input frame
+luminance plane.
+
+This filter computes the bounding box containing all the pixels with a
+luminance value greater than the minimum allowed value.
+The parameters describing the bounding box are printed on the filter
+log.
+
+@section blackdetect
+
+Detect video intervals that are (almost) completely black. Can be
+useful to detect chapter transitions, commercials, or invalid
+recordings. Output lines contains the time for the start, end and
+duration of the detected black interval expressed in seconds.
+
+In order to display the output lines, you need to set the loglevel at
+least to the AV_LOG_INFO value.
+
+This filter accepts a list of options in the form of
+@var{key}=@var{value} pairs separated by ":". A description of the
+accepted options follows.
+
+@table @option
+@item black_min_duration, d
+Set the minimum detected black duration expressed in seconds. It must
+be a non-negative floating point number.
+
+Default value is 2.0.
+
+@item picture_black_ratio_th, pic_th
+Set the threshold for considering a picture "black".
+Express the minimum value for the ratio:
+@example
+@var{nb_black_pixels} / @var{nb_pixels}
+@end example
+
+for which a picture is considered black.
+Default value is 0.98.
+
+@item pixel_black_th, pix_th
+Set the threshold for considering a pixel "black".
+
+The threshold expresses the maximum pixel luminance value for which a
+pixel is considered "black". The provided value is scaled according to
+the following equation:
+@example
+@var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
+@end example
+
+@var{luminance_range_size} and @var{luminance_minimum_value} depend on
+the input video format, the range is [0-255] for YUV full-range
+formats and [16-235] for YUV non full-range formats.
+
+Default value is 0.10.
+@end table
+
+The following example sets the maximum pixel threshold to the minimum
+value, and detects only black intervals of 2 or more seconds:
+@example
+blackdetect=d=2:pix_th=0.00
+@end example
+
@section blackframe
Detect frames that are (almost) completely black. Can be useful to
Apply boxblur algorithm to the input video.
This filter accepts the parameters:
-@var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
+@var{luma_radius}:@var{luma_power}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
Chroma and alpha parameters are optional, if not specified they default
to the corresponding values set for @var{luma_radius} and
@end itemize
+@section colormatrix
+
+The colormatrix filter allows conversion between any of the following color
+space: BT.709 (@var{bt709}), BT.601 (@var{bt601}), SMPTE-240M (@var{smpte240m})
+and FCC (@var{fcc}).
+
+The syntax of the parameters is @var{source}:@var{destination}:
+
+@example
+colormatrix=bt601:smpte240m
+@end example
+
@section copy
Copy the input source unchanged to the output. Mainly useful for
@section crop
-Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
+Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}
-The parameters are expressions containing the following constants:
+The @var{keep_aspect} parameter is optional, if specified and set to a
+non-zero value will force the output display aspect ratio to be the
+same of the input, by changing the output sample aspect ratio.
-@table @option
-@item E, PI, PHI
-the corresponding mathematical approximated values for e
-(euler number), pi (greek PI), PHI (golden ratio)
+The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
+expressions containing the following constants:
+@table @option
@item x, y
the computed values for @var{x} and @var{y}. They are evaluated for
each new frame.
@item ow, oh
same as @var{out_w} and @var{out_h}
+@item a
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+
+@item hsub, vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
@item n
the number of input frame, starting from 0
playback.
@end table
+@section decimate
+
+This filter drops frames that do not differ greatly from the previous
+frame in order to reduce framerate. The main use of this filter is
+for very-low-bitrate encoding (e.g. streaming over dialup modem), but
+it could in theory be used for fixing movies that were
+inverse-telecined incorrectly.
+
+It accepts the following parameters:
+@var{max}:@var{hi}:@var{lo}:@var{frac}.
+
+@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, lo, frac
+Set the dropping threshold values.
+
+Values for @var{hi} and @var{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 @var{hi}, and if no more than @var{frac} blocks (1
+meaning the whole image) differ by more than a threshold of @var{lo}.
+
+Default value for @var{hi} is 64*12, default value for @var{lo} is
+64*5, and default value for @var{frac} is 0.33.
+@end table
+
@section delogo
Suppress a TV station logo by a simple interpolation of the surrounding
@end itemize
+@section deshake
+
+Attempt to fix small changes in horizontal and/or vertical shift. This
+filter helps remove camera shake from hand-holding a camera, bumping a
+tripod, moving on a vehicle, etc.
+
+The filter accepts parameters as a string of the form
+"@var{x}:@var{y}:@var{w}:@var{h}:@var{rx}:@var{ry}:@var{edge}:@var{blocksize}:@var{contrast}:@var{search}:@var{filename}"
+
+A description of the accepted parameters follows.
+
+@table @option
+
+@item x, y, w, h
+Specify a rectangular area where to limit the search for motion
+vectors.
+If desired the search for motion vectors can be limited to a
+rectangular area of the frame defined by its top left corner, width
+and height. These parameters have the same meaning as the drawbox
+filter which can be used to visualise the position of the bounding
+box.
+
+This is useful when simultaneous movement of subjects within the frame
+might be confused for camera motion by the motion vector search.
+
+If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
+then the full frame is used. This allows later options to be set
+without specifying the bounding box for the motion vector search.
+
+Default - search the whole frame.
+
+@item rx, ry
+Specify the maximum extent of movement in x and y directions in the
+range 0-64 pixels. Default 16.
+
+@item edge
+Specify how to generate pixels to fill blanks at the edge of the
+frame. An integer from 0 to 3 as follows:
+@table @option
+@item 0
+Fill zeroes at blank locations
+@item 1
+Original image at blank locations
+@item 2
+Extruded edge value at blank locations
+@item 3
+Mirrored edge at blank locations
+@end table
+
+The default setting is mirror edge at blank locations.
+
+@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 0 = exhaustive search, 1 = less exhaustive
+search. Default - exhaustive search.
+
+@item filename
+If set then a detailed log of the motion search is written to the
+specified file.
+
+@end table
+
@section drawbox
Draw a colored box on the input image.
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 Libav with
+To enable compilation of this filter you need to configure FFmpeg with
@code{--enable-libfreetype}.
The filter also recognizes strftime() sequences in the provided text
@table @option
-@item fontfile
-The font file to be used for drawing text. Path must be included.
-This parameter is mandatory.
-
-@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 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 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 text and textfile are specified, an error is thrown.
-
-@item x, y
-The offsets where text will be drawn within the video frame.
-Relative to the top/left border of the output image.
-They accept expressions similar to the @ref{overlay} filter:
-@table @option
-
-@item x, y
-the computed values for @var{x} and @var{y}. They are evaluated for
-each new frame.
-
-@item main_w, main_h
-main input width and height
-
-@item W, H
-same as @var{main_w} and @var{main_h}
-
-@item text_w, text_h
-rendered text width and height
-
-@item w, h
-same as @var{text_w} and @var{text_h}
-
-@item n
-the number of frames processed, starting from 0
+@item boxcolor
+The color to be used for drawing box around text.
+Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
+(e.g. "0xff00ff"), possibly followed by an alpha specifier.
+The default value of @var{boxcolor} is "white".
-@item t
-timestamp expressed in seconds, NAN if the input timestamp is unknown
+@item draw
+Set an expression which specifies if the text should be drawn. If the
+expression evaluates to 0, the text is not drawn. This is useful for
+specifying that the text should be drawn only when specific conditions
+are met.
-@end table
+Default value is "1".
-The default value of @var{x} and @var{y} is 0.
+See below for the list of accepted constants and functions.
-@item fontsize
-The font size to be used for drawing text.
-The default value of @var{fontsize} is 16.
+@item fix_bounds
+If true, check and fix text coords to avoid clipping.
@item fontcolor
The color to be used for drawing fonts.
(e.g. "0xff000033"), possibly followed by an alpha specifier.
The default value of @var{fontcolor} is "black".
-@item boxcolor
-The color to be used for drawing box around text.
-Either a string (e.g. "yellow") or in 0xRRGGBB[AA] format
-(e.g. "0xff00ff"), possibly followed by an alpha specifier.
-The default value of @var{boxcolor} is "white".
-
-@item 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 shadowx, shadowy
-The x and y offsets for the text shadow position with respect to the
-position of the text. They can be either positive or negative
-values. Default value for both is "0".
+@item fontfile
+The font file to be used for drawing text. Path must be included.
+This parameter is mandatory.
-@item shadowcolor
-The color to be used for drawing a shadow behind the drawn text. It
-can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
-form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
-The default value of @var{shadowcolor} is "black".
+@item 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.
For more information consult the documentation for the FT_LOAD_*
libfreetype flags.
+@item shadowcolor
+The color to be used for drawing a shadow behind the drawn text. It
+can be a color name (e.g. "yellow") or a string in the 0xRRGGBB[AA]
+form (e.g. "0xff00ff"), possibly followed by an alpha specifier.
+The default value of @var{shadowcolor} is "black".
+
+@item shadowx, shadowy
+The x and y offsets for the text shadow position with respect to the
+position of the text. They can be either positive or negative
+values. Default value for both is "0".
+
@item tabsize
The size in number of spaces to use for rendering the tab.
Default value is 4.
-@item fix_bounds
-If true, check and fix text coords to avoid clipping.
+@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 x, y
+The expressions which specify the offsets where text will be drawn
+within the video frame. They are relative to the top/left border of the
+output image.
+
+The default value of @var{x} and @var{y} is "0".
+
+See below for the list of accepted constants and functions.
@end table
-For example the command:
+The parameters for @var{x} and @var{y} are expressions containing the
+following constants and functions:
+
+@table @option
+@item dar
+input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
+
+@item hsub, vsub
+horizontal and vertical chroma subsample values. For example for the
+pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
+
+@item line_h, lh
+the height of each text line
+
+@item main_h, h, H
+the input height
+
+@item main_w, w, W
+the input width
+
+@item max_glyph_a, ascent
+the maximum distance from the baseline to the highest/upper grid
+coordinate used to place a glyph outline point, for all the rendered
+glyphs.
+It is a positive value, due to the grid's orientation with the Y axis
+upwards.
+
+@item max_glyph_d, descent
+the maximum distance from the baseline to the lowest grid coordinate
+used to place a glyph outline point, for all the rendered glyphs.
+This is a negative value, due to the grid's orientation, with the Y axis
+upwards.
+
+@item max_glyph_h
+maximum glyph height, that is the maximum height for all the glyphs
+contained in the rendered text, it is equivalent to @var{ascent} -
+@var{descent}.
+
+@item max_glyph_w
+maximum glyph width, that is the maximum width for all the glyphs
+contained in the rendered text
+
+@item n
+the number of input frame, starting from 0
+
+@item rand(min, max)
+return a random number included between @var{min} and @var{max}
+
+@item sar
+input sample aspect ratio
+
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
+
+@item text_h, th
+the height of the rendered text
+
+@item text_w, tw
+the width of the rendered text
+
+@item x, y
+the x and y offset coordinates where the text is drawn.
+
+These parameters allow the @var{x} and @var{y} expressions to refer
+each other, so you can for example specify @code{y=x/dar}.
+@end table
+
+If libavfilter was built with @code{--enable-fontconfig}, then
+@option{fontfile} can be a fontconfig pattern or omitted.
+
+Some examples follow.
+
+@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
-will draw "Test Text" with font FreeSerif, using the default values
-for the optional parameters.
+@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%.
-The command:
@example
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
@end example
-will draw 'Test Text' with font FreeSerif of size 24 at position x=100
-and y=50 (counting from the top-left corner of the screen), text is
-yellow with a red box around it. Both the text and the box have an
-opacity of 20%.
-
Note that the double quotes are not necessary if spaces are not used
within the parameter list.
+@item
+Show the text at the center of the video frame:
+@example
+drawtext="fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
+@end example
+
+@item
+Show a text line sliding from right to left in the last row of the video
+frame. The file @file{LONG_LINE} is assumed to contain a single line
+with no newlines.
+@example
+drawtext="fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t"
+@end example
+
+@item
+Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
+@example
+drawtext="fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
+@end example
+
+@item
+Draw a single green letter "g", at the center of the input video.
+The glyph baseline is placed at half screen height.
+@example
+drawtext="fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent"
+@end example
+
+@item
+Show text for 1 second every 3 seconds:
+@example
+drawtext="fontfile=FreeSerif.ttf:fontcolor=white:x=100:y=x/dar:draw=lt(mod(t\,3)\,1):text='blink'"
+@end example
+
+@item
+Use fontconfig to set the font. Note that the colons need to be escaped.
+@example
+drawtext='fontfile=Linux Libertine O-40\:style=Semibold:text=FFmpeg'
+@end example
+
+@end itemize
+
For more information about libfreetype, check:
@url{http://www.freetype.org/}.
+For more information about fontconfig, check:
+@url{http://freedesktop.org/software/fontconfig/fontconfig-user.html}.
+
+@section edgedetect
+
+Detect and draw edges. The filter uses the Canny Edge Detection algorithm.
+
+This filter accepts the following optional named parameters:
+
+@table @option
+@item low, high
+Set low and high threshold values used by the Canny thresholding
+algorithm.
+
+The high threshold selects the "strong" edge pixels, which are then
+connected through 8-connectivity with the "weak" edge pixels selected
+by the low threshold.
+
+@var{low} and @var{high} threshold values must be choosen in the range
+[0,1], and @var{low} should be lesser or equal to @var{high}.
+
+Default value for @var{low} is @code{20/255}, and default value for @var{high}
+is @code{50/255}.
+@end table
+
+Example:
+@example
+edgedetect=low=0.1:high=0.4
+@end example
+
@section fade
Apply fade-in/out effect to input video.
It accepts the parameters:
-@var{type}:@var{start_frame}:@var{nb_frames}
+@var{type}:@var{start_frame}:@var{nb_frames}[:@var{options}]
@var{type} specifies if the effect type, can be either "in" for
fade-in, or "out" for a fade-out effect.
will have the same intensity as the input video, at the end of the
fade-out transition the output video will be completely black.
+@var{options} is an optional sequence of @var{key}=@var{value} pairs,
+separated by ":". The description of the accepted options follows.
+
+@table @option
+
+@item type, t
+See @var{type}.
+
+@item start_frame, s
+See @var{start_frame}.
+
+@item nb_frames, n
+See @var{nb_frames}.
+
+@item alpha
+If set to 1, fade only alpha channel, if one exists on the input.
+Default value is 0.
+@end table
+
A few usage examples follow, usable too as test scenarios.
@example
# fade in first 30 frames of video
# make first 5 frames black, then fade in from frame 5-24
fade=in:5:20
+
+# fade in alpha over first 25 frames of video
+fade=in:0:25:alpha=1
@end example
@section fieldorder
For example:
@example
-./avconv -i in.vob -vf "fieldorder=bff" out.dv
+ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
@end example
@section fifo
@item fps
Desired output framerate.
+@item round
+Rounding method. The default is @code{near}.
+
@end table
+@section framestep
+
+Select one frame every N.
+
+This filter accepts in input a string representing a positive
+integer. Default argument is @code{1}.
+
@anchor{frei0r}
@section frei0r
Apply a frei0r effect to the input video.
To enable compilation of this filter you need to install the frei0r
-header and configure Libav with --enable-frei0r.
+header and configure FFmpeg with @code{--enable-frei0r}.
The filter supports the syntax:
@example
effect parameter is not specified the default value is set.
Some examples follow:
+
+@itemize
+@item
+Apply the distort0r effect, set the first two double parameters:
@example
-# apply the distort0r effect, set the first two double parameters
frei0r=distort0r:0.5:0.01
+@end example
-# apply the colordistance effect, takes a color as first parameter
+@item
+Apply the colordistance effect, takes a color as first parameter:
+@example
frei0r=colordistance:0.2/0.3/0.4
frei0r=colordistance:violet
frei0r=colordistance:0x112233
+@end example
-# apply the perspective effect, specify the top left and top right
-# image positions
+@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://piksel.org/frei0r}
+@url{http://frei0r.dyne.org}
@section gradfun
Fix the banding artifacts that are sometimes introduced into nearly flat
-regions by truncation to 8bit colordepth.
+regions by truncation to 8bit color depth.
Interpolate the gradients that should go where the bands are, and
dither them.
Flip the input video horizontally.
-For example to horizontally flip the input video with @command{avconv}:
+For example to horizontally flip the input video with @command{ffmpeg}:
@example
-avconv -i in.avi -vf "hflip" out.avi
+ffmpeg -i in.avi -vf "hflip" out.avi
@end example
@section hqdn3d
@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
@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.
+@section hue
-@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
-to an RGB input video.
+Modify the hue and/or the saturation of the input.
-These filters accept in input a ":"-separated list of options, which
-specify the expressions used for computing the lookup table for the
-corresponding pixel component values.
+This filter accepts the following optional named options:
-The @var{lut} filter requires either YUV or RGB pixel formats in
-input, and accepts the options:
@table @option
-@var{c0} (first pixel component)
-@var{c1} (second pixel component)
-@var{c2} (third pixel component)
-@var{c3} (fourth pixel component, corresponds to the alpha component)
-@end table
-
-The exact component associated to each option depends on the format in
-input.
+@item h
+Specify the hue angle as a number of degrees. It accepts a float
+number or an expression, and defaults to 0.0.
-The @var{lutrgb} filter requires RGB pixel formats in input, and
-accepts the options:
-@table @option
-@var{r} (red component)
-@var{g} (green component)
-@var{b} (blue component)
-@var{a} (alpha component)
-@end table
+@item H
+Specify the hue angle as a number of degrees. It accepts a float
+number or an expression, and defaults to 0.0.
-The @var{lutyuv} filter requires YUV pixel formats in input, and
-accepts the options:
-@table @option
-@var{y} (Y/luminance component)
-@var{u} (U/Cb component)
-@var{v} (V/Cr component)
-@var{a} (alpha component)
+@item s
+Specify the saturation in the [-10,10] range. It accepts a float number and
+defaults to 1.0.
@end table
-The expressions can contain the following constants and functions:
+The @var{h}, @var{H} and @var{s} parameters are expressions 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 n
+frame count of the input frame starting from 0
-@item val
-input value for the pixel component
+@item pts
+presentation timestamp of the input frame expressed in time base units
-@item clipval
-the input value clipped in the @var{minval}-@var{maxval} range
+@item r
+frame rate of the input video, NAN if the input frame rate is unknown
-@item maxval
-maximum value for the pixel component
+@item t
+timestamp expressed in seconds, NAN if the input timestamp is unknown
-@item minval
-minimum value for the pixel component
+@item tb
+time base of the input video
+@end table
-@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"
+The options can also be set using the syntax: @var{hue}:@var{saturation}
-@item clip(val)
-the computed value in @var{val} clipped in the
-@var{minval}-@var{maxval} range
+In this case @var{hue} is expressed in degrees.
-@item gammaval(gamma)
-the computed gamma correction value of the pixel component value
-clipped in the @var{minval}-@var{maxval} range, corresponds to the
+Some examples follow:
+@itemize
+@item
+Set the hue to 90 degrees and the saturation to 1.0:
+@example
+hue=h=90:s=1
+@end example
+
+@item
+Same command but expressing the hue in radians:
+@example
+hue=H=PI/2:s=1
+@end example
+
+@item
+Same command without named options, hue must be expressed in degrees:
+@example
+hue=90:1
+@end example
+
+@item
+Note that "h:s" syntax does not support expressions for the values of
+h and s, so the following example will issue an error:
+@example
+hue=PI/2:1
+@end example
+
+@item
+Rotate hue and make the saturation swing between 0
+and 2 over a period of 1 second:
+@example
+hue="H=2*PI*t: s=sin(2*PI*t)+1"
+@end example
+
+@item
+Apply a 3 seconds saturation fade-in effect starting at 0:
+@example
+hue="s=min(t/3\,1)"
+@end example
+
+The general fade-in expression can be written as:
+@example
+hue="s=min(0\, max((t-START)/DURATION\, 1))"
+@end example
+
+@item
+Apply a 3 seconds saturation fade-out effect starting at 5 seconds:
+@example
+hue="s=max(0\, min(1\, (8-t)/3))"
+@end example
+
+The general fade-out expression can be written as:
+@example
+hue="s=max(0\, min(1\, (START+DURATION-t)/DURATION))"
+@end example
+
+@end itemize
+
+@subsection Commands
+
+This filter supports the following command:
+@table @option
+@item reinit
+Modify the hue and/or the saturation of the input video.
+The command accepts the same named options and syntax than when calling the
+filter from the command-line.
+
+If a parameter is omitted, it is kept at its current value.
+@end table
+
+@section idet
+
+Interlaceing detect filter. This filter tries to detect if the input is
+interlaced or progressive. Top or bottom field first.
+
+@section lut, lutrgb, lutyuv
+
+Compute a look-up table for binding each pixel component input value
+to an output value, and apply it to input video.
+
+@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
+to an RGB input video.
+
+These filters accept in input a ":"-separated list of options, which
+specify the expressions used for computing the lookup table for the
+corresponding pixel component values.
+
+The @var{lut} filter requires either YUV or RGB pixel formats in
+input, and accepts the options:
+@table @option
+@item @var{c0} (first pixel component)
+@item @var{c1} (second pixel component)
+@item @var{c2} (third pixel component)
+@item @var{c3} (fourth pixel component, corresponds to the alpha component)
+@end table
+
+The exact component associated to each option depends on the format in
+input.
+
+The @var{lutrgb} filter requires RGB pixel formats in input, and
+accepts the options:
+@table @option
+@item @var{r} (red component)
+@item @var{g} (green component)
+@item @var{b} (blue component)
+@item @var{a} (alpha component)
+@end table
+
+The @var{lutyuv} filter requires YUV pixel formats in input, and
+accepts the options:
+@table @option
+@item @var{y} (Y/luminance component)
+@item @var{u} (U/Cb component)
+@item @var{v} (V/Cr component)
+@item @var{a} (alpha component)
+@end table
+
+The expressions can contain the following constants and functions:
+
+@table @option
+@item w, h
+the input width and height
+
+@item val
+input value for the pixel component
+
+@item clipval
+the input value clipped in the @var{minval}-@var{maxval} range
+
+@item maxval
+maximum value for the pixel component
+
+@item minval
+minimum value for the pixel component
+
+@item negval
+the negated value for the pixel component value clipped in the
+@var{minval}-@var{maxval} range , it corresponds to the expression
+"maxval-clipval+minval"
+
+@item clip(val)
+the computed value in @var{val} clipped in the
+@var{minval}-@var{maxval} range
+
+@item gammaval(gamma)
+the computed gamma correction value of the pixel component value
+clipped in the @var{minval}-@var{maxval} range, corresponds to the
expression
"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
lutyuv="y=negval:u=negval:v=negval"
# negate luminance
-lutyuv=negval
+lutyuv=y=negval
# remove chroma components, turns the video into a graytone image
lutyuv="u=128:v=128"
lutyuv=y=gammaval(0.5)
@end example
+@section mp
+
+Apply an MPlayer filter to the input video.
+
+This filter provides a wrapper around most of the filters of
+MPlayer/MEncoder.
+
+This wrapper is considered experimental. Some of the wrapped filters
+may not work properly and we may drop support for them, as they will
+be implemented natively into FFmpeg. Thus you should avoid
+depending on them when writing portable scripts.
+
+The filters accepts the parameters:
+@var{filter_name}[:=]@var{filter_params}
+
+@var{filter_name} is the name of a supported MPlayer filter,
+@var{filter_params} is a string containing the parameters accepted by
+the named filter.
+
+The list of the currently supported filters follows:
+@table @var
+@item denoise3d
+@item detc
+@item dint
+@item divtc
+@item down3dright
+@item dsize
+@item eq2
+@item eq
+@item field
+@item fil
+@item fixpts
+@item fspp
+@item geq
+@item harddup
+@item hqdn3d
+@item il
+@item ilpack
+@item ivtc
+@item kerndeint
+@item mcdeint
+@item noise
+@item ow
+@item palette
+@item perspective
+@item phase
+@item pp7
+@item pullup
+@item qp
+@item rectangle
+@item sab
+@item softpulldown
+@item softskip
+@item spp
+@item telecine
+@item tile
+@item tinterlace
+@item unsharp
+@item uspp
+@item yuvcsp
+@item yvu9
+@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.
+
+Some examples follow:
+@itemize
+@item
+Adjust gamma, brightness, contrast:
+@example
+mp=eq2=1.0:2:0.5
+@end example
+
+@item
+Add temporal noise to input video:
+@example
+mp=noise=20t
+@end example
+@end itemize
+
+See also mplayer(1), @url{http://www.mplayerhq.hu/}.
+
@section negate
Negate input video.
This filter accepts an integer in input, if non-zero it negates the
alpha component (if available). The default value in input is 0.
+@section noformat
+
Force libavfilter not to use any of the specified pixel formats for the
input to the next filter.
Apply video transform using libopencv.
To enable this filter install libopencv library and headers and
-configure Libav with --enable-libopencv.
+configure FFmpeg with @code{--enable-libopencv}.
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
It takes two inputs and one output, the first input is the "main"
video on which the second input is overlayed.
-It accepts the parameters: @var{x}:@var{y}.
+It accepts the parameters: @var{x}:@var{y}[:@var{options}].
@var{x} is the x coordinate of the overlayed video on the main video,
-@var{y} is the y coordinate. The parameters are expressions containing
+@var{y} is the y coordinate. @var{x} and @var{y} are expressions containing
the following parameters:
@table @option
same as @var{overlay_w} and @var{overlay_h}
@end table
+@var{options} is an optional list of @var{key}=@var{value} pairs,
+separated by ":".
+
+The description of the accepted options follows.
+
+@table @option
+@item rgb
+If set to 1, force the filter to accept inputs in the RGB
+color space. Default value is 0.
+@end table
+
Be aware that frames are taken from each input video in timestamp
order, hence, if their initial timestamps differ, it is a a good idea
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
overlay=main_w-overlay_w-10:main_h-overlay_h-10
# insert a transparent PNG logo in the bottom left corner of the input
-avconv -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
+ffmpeg -i input -i logo -filter_complex 'overlay=10:main_h-overlay_h-10' output
# insert 2 different transparent PNG logos (second logo on bottom
# right corner):
-avconv -i input -i logo1 -i logo2 -filter_complex
+ffmpeg -i input -i logo1 -i logo2 -filter_complex
'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output
# add a transparent color layer on top of the main video,
# WxH specifies the size of the main input to the overlay filter
-color=red@.3:WxH [over]; [in][over] overlay [out]
+color=red@@.3:WxH [over]; [in][over] overlay [out]
+
+# play an original video and a filtered version (here with the deshake filter)
+# side by side
+ffplay input.avi -vf 'split[a][b]; [a]pad=iw*2:ih[src]; [b]deshake[filt]; [src][filt]overlay=w'
+
+# the previous example is the same as:
+ffplay input.avi -vf 'split[b], pad=iw*2[src], [b]deshake, [src]overlay=w'
@end example
You can chain together more overlays but the efficiency of such
expressions 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 in_w, in_h
the input video width and height
expressions, or NAN if not yet specified
@item a
-input display aspect ratio, same as @var{iw} / @var{ih}
+same as @var{iw} / @var{ih}
+
+@item sar
+input sample aspect ratio
+
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
@item hsub, vsub
horizontal and vertical chroma subsample values. For example for the
@end table
-Some examples follow:
+@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
-# Add paddings with color "violet" to the input video. Output video
-# size is 640x480, the top-left corner of the input video is placed at
-# column 0, row 40.
pad=640:480:0:40:violet
+@end example
-# pad the input to get an output with dimensions increased bt 3/2,
-# and put the input video at the center of the padded area
+@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
-# 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
+@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
-# pad the input to get a final w/h ratio of 16:9
+@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
-# double output size and put the input video in the bottom-right
-# corner of the output padded area
+@item
+Double output size and put the input video in the bottom-right
+corner of the output padded area:
+@example
pad="2*iw:2*ih:ow-iw:oh-ih"
@end example
+@end itemize
@section pixdesctest
can be used to test the monowhite pixel format descriptor definition.
+@section removelogo
+
+Suppress a TV station logo, using an image file to determine which
+pixels comprise the logo. It works by filling in the pixels that
+comprise the logo with neighboring pixels.
+
+This filter requires one argument which specifies the filter bitmap
+file, which can be any image format supported by libavformat. The
+width and height of the image file must match those of the video
+stream being processed.
+
+Pixels in the provided bitmap image with a value of zero are not
+considered part of the logo, non-zero pixels are considered part of
+the logo. If you use white (255) for the logo and black (0) for the
+rest, you will be safe. For making the filter bitmap, it is
+recommended to take a screen capture of a black frame with the logo
+visible, and then using a threshold filter followed by the erode
+filter once or twice.
+
+If needed, little splotches can be fixed manually. Remember that if
+logo pixels are not covered, the filter quality will be much
+reduced. Marking too many pixels as part of the logo does not hurt as
+much, but it will increase the amount of blurring needed to cover over
+the image and will destroy more information than necessary, and extra
+pixels will slow things down on a large logo.
+
@section scale
-Scale the input video to @var{width}:@var{height} and/or convert the image format.
+Scale (resize) the input video to @var{width}:@var{height}[:@var{interl}=@{1|-1@}] and/or convert the image format.
+
+The scale filter forces the output display aspect ratio to be the same
+of the input, by changing the output sample aspect ratio.
The parameters @var{width} and @var{height} are expressions 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 in_w, in_h
the input width and height
@item ow, oh
same as @var{out_w} and @var{out_h}
-@item dar, a
-input display aspect ratio, same as @var{iw} / @var{ih}
+@item a
+same as @var{iw} / @var{ih}
@item sar
input sample aspect ratio
+@item dar
+input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
+
@item hsub, vsub
horizontal and vertical chroma subsample values. For example for the
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
The default value of @var{width} and @var{height} is 0.
+Valid values for the optional parameter @var{interl} are:
+
+@table @option
+@item 1
+force interlaced aware scaling
+
+@item -1
+select interlaced aware scaling depending on whether the source frames
+are flagged as interlaced or not
+@end table
+
+Unless @var{interl} is set to one of the above options, interlaced scaling will not be used.
+
Some examples follow:
@example
# scale the input video to a size of 200x100.
# the above is the same as
scale=2*in_w:2*in_h
+# scale the input to 2x with forced interlaced scaling
+scale=2*iw:2*ih:interl=1
+
# scale the input to half size
scale=iw/2:ih/2
The expression can contain the following constants:
@table @option
-@item PI
-Greek PI
-
-@item PHI
-golden ratio
-
-@item E
-Euler number
-
@item n
the sequential number of the filtered frame, starting from 0
@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
+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".
select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
@end example
-@anchor{setdar}
-@section setdar
+Complete example to create a mosaic of the first scenes:
-Set the Display Aspect Ratio for the filter output video.
+@example
+ffmpeg -i video.avi -vf select='gt(scene\,0.4)',scale=160:120,tile -frames:v 1 preview.png
+@end example
-This is done by changing the specified Sample (aka Pixel) Aspect
-Ratio, according to the following equation:
-@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
+Comparing @var{scene} against a value between 0.3 and 0.5 is generally a sane
+choice.
-Keep in mind that this filter does not modify the pixel dimensions of
-the video frame. Also the display aspect ratio set by this filter may
-be changed by later filters in the filterchain, e.g. in case of
-scaling or if another "setdar" or a "setsar" filter is applied.
+@section setdar, setsar
-The filter accepts a parameter string which represents the wanted
-display aspect ratio.
-The parameter can be a floating point number string, or an expression
-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 "0:1".
+The @code{setdar} filter sets the Display Aspect Ratio for the filter
+output video.
-For example to change the display aspect ratio to 16:9, specify:
+This is done by changing the specified Sample (aka Pixel) Aspect
+Ratio, according to the following equation:
@example
-setdar=16:9
-# the above is equivalent to
-setdar=1.77777
+@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
@end example
-See also the @ref{setsar} filter documentation.
+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.
-@section setpts
+The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
+the filter output video.
-Change the PTS (presentation timestamp) of the input video frames.
+Note that as a consequence of the application of this filter, the
+output display aspect ratio will change according to the equation
+above.
-Accept in input an expression evaluated through the eval API, which
-can contain the following constants:
+Keep in mind that the sample aspect ratio set by the @code{setsar}
+filter may be changed by later filters in the filterchain, e.g. if
+another "setsar" or a "setdar" filter is applied.
+
+The @code{setdar} and @code{setsar} filters accept a string in the
+form @var{num}:@var{den} expressing an aspect ratio, or the following
+named options, expressed as a sequence of @var{key}=@var{value} pairs,
+separated by ":".
@table @option
-@item PTS
-the presentation timestamp in input
+@item max
+Set the maximum integer value to use for expressing numerator and
+denominator when reducing the expressed aspect ratio to a rational.
+Default value is @code{100}.
+
+@item r, ratio:
+Set the aspect ratio used by the filter.
+
+The parameter can be a floating point number string, an expression, or
+a string of the form @var{num}:@var{den}, where @var{num} and
+@var{den} are the numerator and denominator of the aspect ratio. If
+the parameter is not specified, it is assumed the value "0".
+In case the form "@var{num}:@var{den}" the @code{:} character should
+be escaped.
+@end table
-@item PI
-Greek PI
+If the keys are omitted in the named options list, the specifed values
+are assumed to be @var{ratio} and @var{max} in that order.
-@item PHI
-golden ratio
+For example to change the display aspect ratio to 16:9, specify:
+@example
+setdar='16:9'
+@end example
-@item E
-Euler number
+The example above is equivalent to:
+@example
+setdar=1.77777
+@end example
-@item N
-the count of the input frame, starting from 0.
+To change the sample aspect ratio to 10:11, specify:
+@example
+setsar='10:11'
+@end example
-@item STARTPTS
-the PTS of the first video frame
+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
-@item INTERLACED
-tell if the current frame is interlaced
+@section setfield
-@item POS
-original position in the file of the frame, or undefined if undefined
-for the current frame
+Force field for the output video frame.
-@item PREV_INPTS
-previous input PTS
+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}).
-@item PREV_OUTPTS
-previous output PTS
+It accepts a string parameter, which can assume the following values:
+@table @samp
+@item auto
+Keep the same field property.
-@end table
+@item bff
+Mark the frame as bottom-field-first.
-Some examples follow:
+@item tff
+Mark the frame as top-field-first.
-@example
-# start counting PTS from zero
-setpts=PTS-STARTPTS
+@item prog
+Mark the frame as progressive.
+@end table
-# fast motion
-setpts=0.5*PTS
+@section showinfo
-# slow motion
-setpts=2.0*PTS
+Show a line containing various information for each input video frame.
+The input video is not modified.
-# fixed rate 25 fps
-setpts=N/(25*TB)
+The shown line contains a sequence of key/value pairs of the form
+@var{key}:@var{value}.
-# fixed rate 25 fps with some jitter
-setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
-@end example
+A description of each shown parameter follows:
-@anchor{setsar}
-@section setsar
+@table @option
+@item n
+sequential number of the input frame, starting from 0
-Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
+@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.
-Note that as a consequence of the application of this filter, the
-output display aspect ratio will change according to the following
-equation:
-@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
+@item pts_time
+Presentation TimeStamp of the input frame, expressed as a number of
+seconds
-Keep in mind that the sample aspect ratio set by this filter may be
-changed by later filters in the filterchain, e.g. if another "setsar"
-or a "setdar" filter is applied.
-
-The filter accepts a parameter string which represents the wanted
-sample aspect ratio.
-The parameter can be a floating point number string, or an expression
-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 "0:1".
-
-For example to change the sample aspect ratio to 10:11, specify:
-@example
-setsar=10:11
-@end example
-
-@section settb
-
-Set the timebase to use for the output frames timestamps.
-It is mainly useful for testing timebase configuration.
-
-It accepts in input an arithmetic expression representing a rational.
-The expression can contain the constants "PI", "E", "PHI", "AVTB" (the
-default timebase), and "intb" (the input timebase).
-
-The default value for the input is "intb".
-
-Follow some examples.
-
-@example
-# set the timebase to 1/25
-settb=1/25
-
-# set the timebase to 1/10
-settb=0.1
-
-#set the timebase to 1001/1000
-settb=1+0.001
-
-#set the timebase to 2*intb
-settb=2*intb
-
-#set the default timebase value
-settb=AVTB
-@end example
-
-@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 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
@file{libavutil/avutil.h}.
@item checksum
-Adler-32 checksum of all the planes of the input frame
+Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
@item plane_checksum
-Adler-32 checksum of each plane of the input frame, expressed in the form
-"[@var{c0} @var{c1} @var{c2} @var{c3}]"
+Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
+expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
@end table
@section slicify
slices.
@example
-./avconv -i in.avi -vf "slicify=32" out.avi
+ffmpeg -i in.avi -vf "slicify=32" out.avi
@end example
The filter accepts the slice height as parameter. If the parameter is
Adding this in the beginning of filter chains should make filtering
faster due to better use of the memory cache.
+@section smartblur
+
+Blur the input video without impacting the outlines.
+
+The filter accepts the following parameters:
+@var{luma_radius}:@var{luma_strength}:@var{luma_threshold}[:@var{chroma_radius}:@var{chroma_strength}:@var{chroma_threshold}]
+
+Parameters prefixed by @var{luma} indicate that they work on the
+luminance of the pixels whereas parameters prefixed by @var{chroma}
+refer to the chrominance of the pixels.
+
+If the chroma parameters are not set, the luma parameters are used for
+either the luminance and the chrominance of the pixels.
+
+@var{luma_radius} or @var{chroma_radius} 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).
+
+@var{luma_strength} or @var{chroma_strength} 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.
+
+@var{luma_threshold} or @var{chroma_threshold} must be an integer in
+the range [-30,30] that is used as a coefficient to determine whether
+a pixel should be blurred or not. 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.
+
@section split
Split input video into several identical outputs.
For example
@example
-avconv -i INPUT -filter_complex split=5 OUTPUT
+ffmpeg -i INPUT -filter_complex split=5 OUTPUT
@end example
will create 5 copies of the input video.
+For example:
+@example
+[in] split [splitout1][splitout2];
+[splitout1] crop=100:100:0:0 [cropout];
+[splitout2] pad=200:200:100:100 [padout];
+@end example
+
+will create two separate outputs from the same input, one cropped and
+one padded.
+
+@section super2xsai
+
+Scale the input by 2x and smooth using the Super2xSaI (Scale and
+Interpolate) pixel art scaling algorithm.
+
+Useful for enlarging pixel art images without reducing sharpness.
+
+@section swapuv
+Swap U & V plane.
+
+@section thumbnail
+Select the most representative frame in a given sequence of consecutive frames.
+
+It accepts as argument the frames batch size to analyze (default @var{N}=100);
+in a set of @var{N} frames, the filter will pick one of them, and then handle
+the next batch of @var{N} frames until the end.
+
+Since the filter keeps track of the whole frames sequence, a bigger @var{N}
+value will result in a higher memory usage, so a high value is not recommended.
+
+The following example extract one picture each 50 frames:
+@example
+thumbnail=50
+@end example
+
+Complete example of a thumbnail creation with @command{ffmpeg}:
+@example
+ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
+@end example
+
+@section tile
+
+Tile several successive frames together.
+
+It accepts as argument the tile size (i.e. the number of lines and columns)
+in the form "@var{w}x@var{h}".
+
+For example, produce 8×8 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.
+
+@section tinterlace
+
+Perform various types of temporal field interlacing.
+
+Frames are counted starting from 1, so the first input frame is
+considered odd.
+
+This filter accepts a single parameter specifying the mode. Available
+modes are:
+
+@table @samp
+@item merge, 0
+Move odd frames into the upper field, even into the lower field,
+generating a double height frame at half framerate.
+
+@item drop_odd, 1
+Only output even frames, odd frames are dropped, generating a frame with
+unchanged height at half framerate.
+
+@item drop_even, 2
+Only output odd frames, even frames are dropped, generating a frame with
+unchanged height at half framerate.
+
+@item pad, 3
+Expand each frame to full height, but pad alternate lines with black,
+generating a frame with double height at the same input framerate.
+
+@item interleave_top, 4
+Interleave the upper field from odd frames with the lower field from
+even frames, generating a frame with unchanged height at half framerate.
+
+@item interleave_bottom, 5
+Interleave the lower field from odd frames with the upper field from
+even frames, generating a frame with unchanged height at half framerate.
+
+@item interlacex2, 6
+Double frame rate with unchanged height. Frames are inserted each
+containing the second temporal field from the previous input frame and
+the first temporal field from the next input frame. This mode relies on
+the top_field_first flag. Useful for interlaced video displays with no
+field synchronisation.
+@end table
+
+Numeric values are deprecated but are accepted for backward
+compatibility reasons.
+
+Default mode is @code{merge}.
+
@section transpose
Transpose rows with columns in the input video and optionally flip it.
-It accepts a parameter representing an integer, which can assume the
-values:
+This filter accepts the following named parameters:
+
+@table @option
+@item dir
+Specify the transposition direction. Can assume the following values:
@table @samp
-@item 0
+@item 0, 4
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
@example
L.R L.l
l.r R.r
@end example
-@item 1
+@item 1, 5
Rotate by 90 degrees clockwise, that is:
@example
L.R l.L
l.r r.R
@end example
-@item 2
+@item 2, 6
Rotate by 90 degrees counterclockwise, that is:
@example
L.R R.r
l.r L.l
@end example
-@item 3
+@item 3, 7
Rotate by 90 degrees clockwise and vertically flip, that is:
@example
L.R r.R
@end example
@end table
+For values between 4-7, the transposition is only done if the input
+video geometry is portrait and not landscape. These values are
+deprecated, the @code{passthrough} option should be used instead.
+
+@item passthrough
+Do not apply the transposition if the input geometry matches the one
+specified by the specified value. It accepts the following values:
+@table @samp
+@item none
+Always apply transposition.
+@item portrait
+Preserve portrait geometry (when @var{height} >= @var{width}).
+@item landscape
+Preserve landscape geometry (when @var{width} >= @var{height}).
+@end table
+
+Default value is @code{none}.
+@end table
+
@section unsharp
Sharpen or blur the input video.
Set the chroma matrix vertical size. It can be an integer between 3
and 13, default value is 5.
-@item luma_amount
+@item chroma_amount
Set the chroma effect strength. It can be a float number between -2.0
and 5.0, default value is 0.0.
# Strong blur of both luma and chroma parameters
unsharp=7:7:-2:7:7:-2
-# Use the default values with @command{avconv}
-./avconv -i in.avi -vf "unsharp" out.mp4
+# Use the default values with @command{ffmpeg}
+ffmpeg -i in.avi -vf "unsharp" out.mp4
@end example
@section vflip
Flip the input video vertically.
@example
-./avconv -i in.avi -vf "vflip" out.avi
+ffmpeg -i in.avi -vf "vflip" out.avi
@end example
@section yadif
This source is mainly intended for a programmatic use, in particular
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
-It accepts the following parameters:
-@var{width}:@var{height}:@var{pix_fmt_string}:@var{timebase_num}:@var{timebase_den}:@var{sample_aspect_ratio_num}:@var{sample_aspect_ratio.den}
-
-All the parameters need to be explicitly defined.
-
-Follows the list of the accepted parameters.
+It accepts a list of options in the form of @var{key}=@var{value} pairs
+separated by ":". A description of the accepted options follows.
@table @option
-@item width, height
-Specify the width and height of the buffered video frames.
+@item video_size
+Specify the size (width and height) of the buffered video frames.
-@item pix_fmt_string
+@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 timebase_num, timebase_den
-Specify numerator and denomitor of the timebase assumed by the
-timestamps of the buffered frames.
+@item time_base
+Specify the timebase assumed by the timestamps of the buffered frames.
+
+@item time_base
+Specify the frame rate expected for the video stream.
+
+@item pixel_aspect
+Specify the sample aspect ratio assumed by the video frames.
-@item sample_aspect_ratio.num, sample_aspect_ratio.den
-Specify numerator and denominator of 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=320:240:yuv410p:1:24:1:1
+buffer=size=320x240:pix_fmt=yuv410p:time_base=1/24:pixel_aspect=1/1
@end example
will instruct the source to accept video frames with size 320x240 and
(check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
this example corresponds to:
@example
-buffer=320:240:6:1:24
+buffer=size=320x240:pixfmt=6:time_base=1/24:pixel_aspect=1/1
@end example
-@section color
+Alternatively, the options can be specified as a flat string, but this
+syntax is deprecated:
-Provide an uniformly colored input.
+@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}]
-It accepts the following parameters:
-@var{color}:@var{frame_size}:@var{frame_rate}
+@section cellauto
-Follows the description of the accepted parameters.
+Create a pattern generated by an elementary cellular automaton.
-@table @option
+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.
-@item color
-Specify the color of the source. It can be the name of a color (case
-insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
-alpha specifier. The default value is "black".
+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.
-@item frame_size
-Specify the size of the sourced video, it may be a string of the form
-@var{width}x@var{height}, or the name of a size abbreviation. The
-default value is "320x240".
+This source accepts a list of options in the form of
+@var{key}=@var{value} pairs separated by ":". A description of the
+accepted options follows.
-@item frame_rate
-Specify the frame rate of the sourced video, as the number of frames
-generated per second. It has to be a string in the format
-@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
-number or a valid video frame rate abbreviation. The default value is
-"25".
+@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.
-@end table
+@item pattern, p
+Read the initial cellular automaton state, i.e. the starting row, from
+the specified string.
-For example the following graph description will generate a red source
-with an opacity of 0.2, with size "qcif" and a frame rate of 10
-frames per second, which will be overlayed over the source connected
-to the pad with identifier "in".
+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.
-@example
-"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
-@end example
+@item rate, r
+Set the video rate, that is the number of frames generated per second.
+Default is 25.
-@section movie
+@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.
-Read a video stream from a movie container.
+This option is ignored when a file or a pattern is specified.
-Note that this source is a hack that bypasses the standard input path. It can be
-useful in applications that do not support arbitrary filter graphs, but its use
-is discouraged in those that do. Specifically in @command{avconv} this filter
-should never be used, the @option{-filter_complex} option fully replaces it.
+@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.
-It accepts the syntax: @var{movie_name}[:@var{options}] where
-@var{movie_name} is the name of the resource to read (not necessarily
-a file but also a device or a stream accessed through some protocol),
-and @var{options} is an optional sequence of @var{key}=@var{value}
-pairs, separated by ":".
+@item rule
+Set the cellular automaton rule, it is a number ranging from 0 to 255.
+Default value is 110.
-The description of the accepted options follows.
+@item size, s
+Set the size of the output video.
-@table @option
+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.
-@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.
+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.
-@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".
+If a filename or a pattern string is not specified, the size value
+defaults to "320x518" (used for a randomly generated initial state).
-@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".
+@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
-This filter allows to overlay a second video on top of main input of
-a filtergraph as shown in this graph:
+@subsection Examples
+
+@itemize
+@item
+Read the initial state from @file{pattern}, and specify an output of
+size 200x400.
@example
-input -----------> deltapts0 --> overlay --> output
- ^
- |
-movie --> scale--> deltapts1 -------+
+cellauto=f=pattern:s=200x400
@end example
-Some examples follow:
+@item
+Generate a random initial row with a width of 200 cells, with a fill
+ratio of 2/3:
@example
-# skip 3.2 seconds from the start of the avi file in.avi, and overlay it
-# on top of the input labelled as "in".
-movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
-[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
+cellauto=ratio=2/3:s=200x200
+@end example
-# read from a video4linux2 device, and overlay it on top of the input
-# labelled as "in"
-movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
-[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
+@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
-@section nullsrc
+@end itemize
-Null video source, never return images. It is mainly useful as a
-template and to be employed in analysis / debugging tools.
+@section mandelbrot
-It accepts as optional parameter a string of the form
-@var{width}:@var{height}:@var{timebase}.
+Generate a Mandelbrot set fractal, and progressively zoom towards the
+point specified with @var{start_x} and @var{start_y}.
-@var{width} and @var{height} specify the size of the configured
-source. The default values of @var{width} and @var{height} are
-respectively 352 and 288 (corresponding to the CIF size format).
+This source accepts a list of options in the form of
+@var{key}=@var{value} pairs separated by ":". A description of the
+accepted options follows.
-@var{timebase} specifies an arithmetic expression representing a
-timebase. The expression can contain the constants "PI", "E", "PHI",
-"AVTB" (the default timebase), and defaults to the value "AVTB".
+@table @option
-@section frei0r_src
+@item end_pts
+Set the terminal pts value. Default value is 400.
-Provide a frei0r source.
+@item end_scale
+Set the terminal scale value.
+Must be a floating point value. Default value is 0.3.
-To enable compilation of this filter you need to install the frei0r
-header and configure Libav with --enable-frei0r.
+@item inner
+Set the inner coloring mode, that is the algorithm used to draw the
+Mandelbrot fractal internal region.
-The source supports the syntax:
-@example
-@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
-@end example
+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
-@var{size} is the size of the video to generate, may be a string of the
-form @var{width}x@var{height} or a frame size abbreviation.
-@var{rate} is the rate of the video to generate, may be a string of
-the form @var{num}/@var{den} or a frame rate abbreviation.
-@var{src_name} is the name to the frei0r source to load. For more
-information regarding frei0r and how to set the parameters read the
-section @ref{frei0r} in the description of the video filters.
+Default value is @var{mincol}.
-Some examples follow:
-@example
-# generate a frei0r partik0l source with size 200x200 and framerate 10
-# which is overlayed on the overlay filter main input
-frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
-@end example
+@item bailout
+Set the bailout value. Default value is 10.0.
-@section rgbtestsrc, testsrc
+@item maxiter
+Set the maximum of iterations performed by the rendering
+algorithm. Default value is 7189.
-The @code{rgbtestsrc} source generates an RGB test pattern useful for
-detecting RGB vs BGR issues. You should see a red, green and blue
-stripe from top to bottom.
+@item 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}.
-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.
+@item rate, r
+Set frame rate, expressed as number of frames per second. Default
+value is "25".
-Both sources accept an optional sequence of @var{key}=@var{value} pairs,
+@item size, s
+Set frame size. Default value is "640x480".
+
+@item start_scale
+Set the initial scale value. Default value is 3.0.
+
+@item start_x
+Set the initial x position. Must be a floating point value between
+-100 and 100. Default value is -0.743643887037158704752191506114774.
+
+@item start_y
+Set the initial y position. Must be a floating point value between
+-100 and 100. Default value is -0.131825904205311970493132056385139.
+@end table
+
+@section mptestsrc
+
+Generate various test patterns, as generated by the MPlayer test filter.
+
+The size of the generated video is fixed, and is 256x256.
+This source is useful in particular for testing encoding features.
+
+This source accepts an optional sequence of @var{key}=@var{value} pairs,
separated by ":". The description of the accepted options follows.
@table @option
-@item size, s
-Specify the size of the sourced video, it may be a string of the form
-@var{width}x@var{height}, or the name of a size abbreviation. The
-default value is "320x240".
-
@item rate, r
Specify the frame rate of the sourced video, as the number of frames
generated per second. It has to be a string in the format
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
+@item duration, d
Set the video duration of the sourced video. The accepted syntax is:
@example
-[-]HH[:MM[:SS[.m...]]]
+[-]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=duration=5.3:size=qcif:rate=10
+testsrc=t=dc_luma
@end example
-will generate a video with a duration of 5.3 seconds, with size
-176x144 and a framerate of 10 frames per second.
+will generate a "dc_luma" test pattern.
-@c man end VIDEO SOURCES
+@section frei0r_src
-@chapter Video Sinks
-@c man begin VIDEO SINKS
+Provide a frei0r source.
-Below is a description of the currently available video sinks.
+To enable compilation of this filter you need to install the frei0r
+header and configure FFmpeg with @code{--enable-frei0r}.
-@section buffersink
+The source supports the syntax:
+@example
+@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
+@end example
-Buffer video frames, and make them available to the end of the filter
-graph.
+@var{size} is the size of the video to generate, may be a string of the
+form @var{width}x@var{height} or a frame size abbreviation.
+@var{rate} is the rate of the video to generate, may be a string of
+the form @var{num}/@var{den} or a frame rate abbreviation.
+@var{src_name} is the name to the frei0r source to load. For more
+information regarding frei0r and how to set the parameters read the
+section @ref{frei0r} in the description of the video filters.
-This sink is intended for a programmatic use through the interface defined in
-@file{libavfilter/buffersink.h}.
+For example, to generate a frei0r partik0l source with size 200x200
+and frame rate 10 which is overlayed on the overlay filter main input:
+@example
+frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
+@end example
+
+@section life
+
+Generate a life pattern.
+
+This source is based on a generalization of John Conway's life game.
+
+The sourced input represents a life grid, each pixel represents a cell
+which can be in one of two possible states, alive or dead. Every cell
+interacts with its eight neighbours, which are the cells that are
+horizontally, vertically, or diagonally adjacent.
+
+At each interaction the grid evolves according to the adopted rule,
+which specifies the number of neighbor alive cells which will make a
+cell stay alive or born. The @option{rule} option allows to specify
+the rule to adopt.
+
+This source accepts a list of options in the form of
+@var{key}=@var{value} pairs separated by ":". A description of the
+accepted options follows.
+
+@table @option
+@item filename, f
+Set the file from which to read the initial grid state. In the file,
+each non-whitespace character is considered an alive cell, and newline
+is used to delimit the end of each row.
+
+If this option is not specified, the initial grid is generated
+randomly.
+
+@item rate, r
+Set the video rate, that is the number of frames generated per second.
+Default is 25.
+
+@item random_fill_ratio, ratio
+Set the random fill ratio for the initial random grid. It is a
+floating point number value ranging from 0 to 1, defaults to 1/PHI.
+It is ignored when a file is specified.
+
+@item random_seed, seed
+Set the seed for filling the initial random grid, must be an integer
+included between 0 and UINT32_MAX. If not specified, or if explicitly
+set to -1, the filter will try to use a good random seed on a best
+effort basis.
+
+@item rule
+Set the life rule.
+
+A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
+where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
+@var{NS} specifies the number of alive neighbor cells which make a
+live cell stay alive, and @var{NB} the number of alive neighbor cells
+which make a dead cell to become alive (i.e. to "born").
+"s" and "b" can be used in place of "S" and "B", respectively.
+
+Alternatively a rule can be specified by an 18-bits integer. The 9
+high order bits are used to encode the next cell state if it is alive
+for each number of neighbor alive cells, the low order bits specify
+the rule for "borning" new cells. Higher order bits encode for an
+higher number of neighbor cells.
+For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
+rule of 12 and a born rule of 9, which corresponds to "S23/B03".
+
+Default value is "S23/B3", which is the original Conway's game of life
+rule, and will keep a cell alive if it has 2 or 3 neighbor alive
+cells, and will born a new cell if there are three alive cells around
+a dead cell.
+
+@item size, s
+Set the size of the output video.
+
+If @option{filename} is specified, the size is set by default to the
+same size of the input file. If @option{size} is set, it must contain
+the size specified in the input file, and the initial grid defined in
+that file is centered in the larger resulting area.
+
+If a filename is not specified, the size value defaults to "320x240"
+(used for a randomly generated initial grid).
+
+@item stitch
+If set to 1, stitch the left and right grid edges together, and the
+top and bottom edges also. Defaults to 1.
+
+@item mold
+Set cell mold speed. If set, a dead cell will go from @option{death_color} to
+@option{mold_color} with a step of @option{mold}. @option{mold} can have a
+value from 0 to 255.
+
+@item life_color
+Set the color of living (or new born) cells.
+
+@item death_color
+Set the color of dead cells. If @option{mold} is set, this is the first color
+used to represent a dead cell.
+
+@item mold_color
+Set mold color, for definitely dead and moldy cells.
+@end table
+
+@subsection Examples
+
+@itemize
+@item
+Read a grid from @file{pattern}, and center it on a grid of size
+300x300 pixels:
+@example
+life=f=pattern:s=300x300
+@end example
+
+@item
+Generate a random grid of size 200x200, with a fill ratio of 2/3:
+@example
+life=ratio=2/3:s=200x200
+@end example
+
+@item
+Specify a custom rule for evolving a randomly generated grid:
+@example
+life=rule=S14/B34
+@end example
+
+@item
+Full example with slow death effect (mold) using @command{ffplay}:
+@example
+ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
+@end example
+@end itemize
+
+@section color, nullsrc, rgbtestsrc, smptebars, testsrc
+
+The @code{color} source provides an uniformly colored input.
+
+The @code{nullsrc} source returns unprocessed video frames. It is
+mainly useful to be employed in analysis / debugging tools, or as the
+source for filters which ignore the input data.
+
+The @code{rgbtestsrc} source generates an RGB test pattern useful for
+detecting RGB vs BGR issues. You should see a red, green and blue
+stripe from top to bottom.
+
+The @code{smptebars} source generates a color bars pattern, based on
+the SMPTE Engineering Guideline EG 1-1990.
+
+The @code{testsrc} source generates a test video pattern, showing a
+color pattern, a scrolling gradient and a timestamp. This is mainly
+intended for testing purposes.
+
+These sources accept an optional sequence of @var{key}=@var{value} pairs,
+separated by ":". The description of the accepted options follows.
+
+@table @option
+
+@item color, c
+Specify the color of the source, only used in the @code{color}
+source. It can be the name of a color (case insensitive match) or a
+0xRRGGBB[AA] sequence, possibly followed by an alpha specifier. The
+default value is "black".
+
+@item size, s
+Specify the size of the sourced video, it may be a string of the form
+@var{width}x@var{height}, or the name of a size abbreviation. The
+default value is "320x240".
+
+@item rate, r
+Specify the frame rate of the sourced video, as the number of frames
+generated per second. It has to be a string in the format
+@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
+number or a valid video frame rate abbreviation. The default value is
+"25".
+
+@item sar
+Set the sample aspect ratio of the sourced video.
+
+@item duration, d
+Set the video duration of the sourced video. The accepted syntax is:
+@example
+[-]HH[:MM[:SS[.m...]]]
+[-]S+[.m...]
+@end example
+See also the function @code{av_parse_time()}.
+
+If not specified, or the expressed duration is negative, the video is
+supposed to be generated forever.
+
+@item decimals, n
+Set the number of decimals to show in the timestamp, only used in the
+@code{testsrc} source.
+
+The displayed timestamp value will correspond to the original
+timestamp value multiplied by the power of 10 of the specified
+value. Default value is 0.
+@end table
+
+For example the following:
+@example
+testsrc=duration=5.3:size=qcif:rate=10
+@end example
+
+will generate a video with a duration of 5.3 seconds, with size
+176x144 and a frame rate of 10 frames per second.
+
+The following graph description will generate a red source
+with an opacity of 0.2, with size "qcif" and a frame rate of 10
+frames per second.
+@example
+color=c=red@@0.2:s=qcif:r=10
+@end example
+
+If the input content is to be ignored, @code{nullsrc} can be used. The
+following command generates noise in the luminance plane by employing
+the @code{mp=geq} filter:
+@example
+nullsrc=s=256x256, mp=geq=random(1)*255:128:128
+@end example
+
+@c man end VIDEO SOURCES
+
+@chapter Video Sinks
+@c man begin VIDEO SINKS
+
+Below is a description of the currently available video sinks.
+
+@section buffersink
+
+Buffer video frames, and make them available to the end of the filter
+graph.
+
+This sink is mainly intended for a programmatic use, in particular
+through the interface defined in @file{libavfilter/buffersink.h}.
+
+It does not require a string parameter in input, but you need to
+specify a pointer to a list of supported pixel formats terminated by
+-1 in the opaque parameter provided to @code{avfilter_init_filter}
+when initializing this sink.
@section nullsink
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 asendcmd, sendcmd
+
+Send commands to filters in the filtergraph.
+
+These filters read commands to be sent to other filters in the
+filtergraph.
+
+@code{asendcmd} must be inserted between two audio filters,
+@code{sendcmd} must be inserted between two video filters, but apart
+from that they act the same way.
+
+The specification of commands can be provided in the filter arguments
+with the @var{commands} option, or in a file specified by the
+@var{filename} option.
+
+These filters accept the following options:
+@table @option
+@item commands, c
+Set the commands to be read and sent to the other filters.
+@item filename, f
+Set the filename of the commands to be read and sent to the other
+filters.
+@end table
+
+@subsection Commands syntax
+
+A commands description consists of a sequence of interval
+specifications, comprising a list of commands to be executed when a
+particular event related to that interval occurs. The occurring event
+is typically the current frame time entering or leaving a given time
+interval.
+
+An interval is specified by the following syntax:
+@example
+@var{START}[-@var{END}] @var{COMMANDS};
+@end example
+
+The time interval is specified by the @var{START} and @var{END} times.
+@var{END} is optional and defaults to the maximum time.
+
+The current frame time is considered within the specified interval if
+it is included in the interval [@var{START}, @var{END}), that is when
+the time is greater or equal to @var{START} and is lesser than
+@var{END}.
+
+@var{COMMANDS} consists of a sequence of one or more command
+specifications, separated by ",", relating to that interval. The
+syntax of a command specification is given by:
+@example
+[@var{FLAGS}] @var{TARGET} @var{COMMAND} @var{ARG}
+@end example
+
+@var{FLAGS} is optional and specifies the type of events relating to
+the time interval which enable sending the specified command, and must
+be a non-null sequence of identifier flags separated by "+" or "|" and
+enclosed between "[" and "]".
+
+The following flags are recognized:
+@table @option
+@item enter
+The command is sent when the current frame timestamp enters the
+specified interval. In other words, the command is sent when the
+previous frame timestamp was not in the given interval, and the
+current is.
+
+@item leave
+The command is sent when the current frame timestamp leaves the
+specified interval. In other words, the command is sent when the
+previous frame timestamp was in the given interval, and the
+current is not.
+@end table
+
+If @var{FLAGS} is not specified, a default value of @code{[enter]} is
+assumed.
+
+@var{TARGET} specifies the target of the command, usually the name of
+the filter class or a specific filter instance name.
+
+@var{COMMAND} specifies the name of the command for the target filter.
+
+@var{ARG} is optional and specifies the optional list of argument for
+the given @var{COMMAND}.
+
+Between one interval specification and another, whitespaces, or
+sequences of characters starting with @code{#} until the end of line,
+are ignored and can be used to annotate comments.
+
+A simplified BNF description of the commands specification syntax
+follows:
+@example
+@var{COMMAND_FLAG} ::= "enter" | "leave"
+@var{COMMAND_FLAGS} ::= @var{COMMAND_FLAG} [(+|"|")@var{COMMAND_FLAG}]
+@var{COMMAND} ::= ["[" @var{COMMAND_FLAGS} "]"] @var{TARGET} @var{COMMAND} [@var{ARG}]
+@var{COMMANDS} ::= @var{COMMAND} [,@var{COMMANDS}]
+@var{INTERVAL} ::= @var{START}[-@var{END}] @var{COMMANDS}
+@var{INTERVALS} ::= @var{INTERVAL}[;@var{INTERVALS}]
+@end example
+
+@subsection Examples
+
+@itemize
+@item
+Specify audio tempo change at second 4:
+@example
+asendcmd=c='4.0 atempo tempo 1.5',atempo
+@end example
+
+@item
+Specify a list of drawtext and hue commands in a file.
+@example
+# show text in the interval 5-10
+5.0-10.0 [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=hello world',
+ [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=';
+
+# desaturate the image in the interval 15-20
+15.0-20.0 [enter] hue reinit s=0,
+ [enter] drawtext reinit 'fontfile=FreeSerif.ttf:text=nocolor',
+ [leave] hue reinit s=1,
+ [leave] drawtext reinit 'fontfile=FreeSerif.ttf:text=color';
+
+# apply an exponential saturation fade-out effect, starting from time 25
+25 [enter] hue s=exp(t-25)
+@end example
+
+A filtergraph allowing to read and process the above command list
+stored in a file @file{test.cmd}, can be specified with:
+@example
+sendcmd=f=test.cmd,drawtext=fontfile=FreeSerif.ttf:text='',hue
+@end example
+@end itemize
+
+@section asetpts, setpts
+
+Change the PTS (presentation timestamp) of the input frames.
+
+@code{asetpts} works on audio frames, @code{setpts} on video frames.
+
+Accept in input an expression evaluated through the eval API, which
+can contain the following constants:
+
+@table @option
+@item FRAME_RATE
+frame rate, only defined for constant frame-rate video
+
+@item PTS
+the presentation timestamp in input
+
+@item N
+the count of the input frame, starting from 0.
+
+@item NB_CONSUMED_SAMPLES
+the number of consumed samples, not including the current frame (only
+audio)
+
+@item NB_SAMPLES
+the number of samples in the current frame (only audio)
+
+@item SAMPLE_RATE
+audio sample rate
+
+@item STARTPTS
+the PTS of the first frame
+
+@item STARTT
+the time in seconds of the first frame
+
+@item INTERLACED
+tell if the current frame is interlaced
+
+@item T
+the time in seconds of the current frame
+
+@item TB
+the time base
+
+@item POS
+original position in the file of the frame, or undefined if undefined
+for the current frame
+
+@item PREV_INPTS
+previous input PTS
+
+@item PREV_INT
+previous input time in seconds
+
+@item PREV_OUTPTS
+previous output PTS
+
+@item PREV_OUTT
+previous output time in seconds
+@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
+@end itemize
+
+@section ebur128
+
+EBU R128 scanner filter. This filter takes an audio stream as input and outputs
+it unchanged. By default, it logs a message at a frequency of 10Hz with the
+Momentary loudness (identified by @code{M}), Short-term loudness (@code{S}),
+Integrated loudness (@code{I}) and Loudness Range (@code{LRA}).
+
+The filter also has a video output (see the @var{video} option) with a real
+time graph to observe the loudness evolution. The graphic contains the logged
+message mentioned above, so it is not printed anymore when this option is set,
+unless the verbose logging is set. The main graphing area contains the
+short-term loudness (3 seconds of analysis), and the gauge on the right is for
+the momentary loudness (400 milliseconds).
+
+More information about the Loudness Recommendation EBU R128 on
+@url{http://tech.ebu.ch/loudness}.
+
+The filter accepts the following named parameters:
+
+@table @option
+
+@item video
+Activate the video output. The audio stream is passed unchanged whether this
+option is set or no. The video stream will be the first output stream if
+activated. Default is @code{0}.
+
+@item size
+Set the video size. This option is for video only. Default and minimum
+resolution is @code{640x480}.
+
+@item meter
+Set the EBU scale meter. Default is @code{9}. Common values are @code{9} and
+@code{18}, respectively for EBU scale meter +9 and EBU scale meter +18. Any
+other integer value between this range is allowed.
+
+@end table
+
+Example of 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
+
+Run an analysis with @command{ffmpeg}:
+@example
+ffmpeg -nostats -i input.mp3 -filter_complex ebur128 -f null -
+@end example
+
+@section settb, asettb
+
+Set the timebase to use for the output frames timestamps.
+It is mainly useful for testing timebase configuration.
+
+It accepts in input an arithmetic expression representing a rational.
+The expression can contain the constants "AVTB" (the
+default timebase), "intb" (the input timebase) and "sr" (the sample rate,
+audio only).
+
+The default value for the input is "intb".
+
+@subsection Examples
+
+@itemize
+@item
+Set the timebase to 1/25:
+@example
+settb=1/25
+@end example
+
+@item
+Set the timebase to 1/10:
+@example
+settb=0.1
+@end example
+
+@item
+Set the timebase to 1001/1000:
+@example
+settb=1+0.001
+@end example
+
+@item
+Set the timebase to 2*intb:
+@example
+settb=2*intb
+@end example
+
+@item
+Set the default timebase value:
+@example
+settb=AVTB
+@end example
+@end itemize
+
+@section concat
+
+Concatenate audio and video streams, joining them together one after the
+other.
+
+The filter works on segments of synchronized video and audio streams. All
+segments must have the same number of streams of each type, and that will
+also be the number of streams at output.
+
+The filter accepts the following named parameters:
+@table @option
+
+@item n
+Set the number of segments. Default is 2.
+
+@item v
+Set the number of output video streams, that is also the number of video
+streams in each segment. Default is 1.
+
+@item a
+Set the number of output audio streams, that is also the number of video
+streams in each segment. Default is 0.
+
+@end table
+
+The filter has @var{v}+@var{a} outputs: first @var{v} video outputs, then
+@var{a} audio outputs.
+
+There are @var{n}×(@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.
+
+Examples:
+@itemize
+@item
+Concatenate an opening, an episode and an ending, all in bilingual version
+(video in stream 0, audio in streams 1 and 2):
+@example
+ffmpeg -i opening.mkv -i episode.mkv -i ending.mkv -filter_complex \
+ '[0:0] [0:1] [0:2] [1:0] [1:1] [1:2] [2:0] [2:1] [2:2]
+ concat=n=3:v=1:a=2 [v] [a1] [a2]' \
+ -map '[v]' -map '[a1]' -map '[a2]' output.mkv
+@end example
+
+@item
+Concatenate two parts, handling audio and video separately, using the
+(a)movie sources, and adjusting the resolution:
+@example
+movie=part1.mp4, scale=512:288 [v1] ; amovie=part1.mp4 [a1] ;
+movie=part2.mp4, scale=512:288 [v2] ; amovie=part2.mp4 [a2] ;
+[v1] [v2] concat [outv] ; [a1] [a2] concat=v=0:a=1 [outa]
+@end example
+Note that a desync will happen at the stitch if the audio and video streams
+do not have exactly the same duration in the first file.
+
+@end itemize
+
+@section showspectrum
+
+Convert input audio to a video output, representing the audio frequency
+spectrum.
+
+The filter accepts the following named parameters:
+@table @option
+@item size, s
+Specify the video size for the output. Default value is @code{640x480}.
+@end table
+
+The usage is very similar to the showwaves filter; see the examples in that
+section.
+
+@section showwaves
+
+Convert input audio to a video output, representing the samples waves.
+
+The filter accepts the following named parameters:
+@table @option
+
+@item n
+Set the number of samples which are printed on the same column. A
+larger value will decrease the frame rate. Must be a positive
+integer. This option can be set only if the value for @var{rate}
+is not explicitly specified.
+
+@item rate, r
+Set the (approximate) output frame rate. This is done by setting the
+option @var{n}. Default value is "25".
+
+@item size, s
+Specify the video size for the output. Default value is "600x240".
+@end table
+
+Some examples follow.
+@itemize
+@item
+Output the input file audio and the corresponding video representation
+at the same time:
+@example
+amovie=a.mp3,asplit[out0],showwaves[out1]
+@end example
+
+@item
+Create a synthetic signal and show it with showwaves, forcing a
+framerate of 30 frames per second:
+@example
+aevalsrc=sin(1*2*PI*t)*sin(880*2*PI*t):cos(2*PI*200*t),asplit[out0],showwaves=r=30[out1]
+@end example
+@end itemize
+
+@c man end MULTIMEDIA FILTERS
+
+@chapter Multimedia Sources
+@c man begin MULTIMEDIA SOURCES
+
+Below is a description of the currently available multimedia sources.
+
+@section amovie
+
+This is the same as @ref{src_movie} source, except it selects an audio
+stream by default.
+
+@anchor{src_movie}
+@section movie
+
+Read audio and/or video stream(s) from a movie container.
+
+It accepts the syntax: @var{movie_name}[:@var{options}] where
+@var{movie_name} is the name of the resource to read (not necessarily
+a file but also a device or a stream accessed through some protocol),
+and @var{options} is an optional sequence of @var{key}=@var{value}
+pairs, separated by ":".
+
+The description of the accepted options follows.
+
+@table @option
+
+@item format_name, f
+Specifies the format assumed for the movie to read, and can be either
+the name of a container or an input device. If not specified the
+format is guessed from @var{movie_name} or by probing.
+
+@item seek_point, sp
+Specifies the seek point in seconds, the frames will be output
+starting from this seek point, the parameter is evaluated with
+@code{av_strtod} so the numerical value may be suffixed by an IS
+postfix. Default value is "0".
+
+@item streams, s
+Specifies the streams to read. Several streams can be specified, separated
+by "+". The source will then have as many outputs, in the same order. The
+syntax is explained in the @ref{Stream specifiers} chapter. 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
+
+Some examples follow.
+
+@itemize
+@item
+Skip 3.2 seconds from the start of the avi file in.avi, and overlay it
+on top of the input labelled as "in":
+@example
+movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
+[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
+@end example
+
+@item
+Read from a video4linux2 device, and overlay it on top of the input
+labelled as "in":
+@example
+movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
+[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
+@end example
+
+@item
+Read the first video stream and the audio stream with id 0x81 from
+dvd.vob; the video is connected to the pad named "video" and the audio is
+connected to the pad named "audio":
+@example
+movie=dvd.vob:s=v:0+#0x81 [video] [audio]
+@end example
+@end itemize
+
+@c man end MULTIMEDIA SOURCES