2396 lines
67 KiB
Plaintext
2396 lines
67 KiB
Plaintext
@chapter Filtergraph description
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@c man begin FILTERGRAPH DESCRIPTION
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A filtergraph is a directed graph of connected filters. It can contain
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cycles, and there can be multiple links between a pair of
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filters. Each link has one input pad on one side connecting it to one
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filter from which it takes its input, and one output pad on the other
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side connecting it to the one filter accepting its output.
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Each filter in a filtergraph is an instance of a filter class
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registered in the application, which defines the features and the
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number of input and output pads of the filter.
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A filter with no input pads is called a "source", a filter with no
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output pads is called a "sink".
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@anchor{Filtergraph syntax}
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@section Filtergraph syntax
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A filtergraph can be represented using a textual representation, which is
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recognized by the @option{-filter}/@option{-vf} and @option{-filter_complex}
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options in @command{avconv} and @option{-vf} in @command{avplay}, and by the
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@code{avfilter_graph_parse()}/@code{avfilter_graph_parse2()} function defined in
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@file{libavfilter/avfiltergraph.h}.
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A filterchain consists of a sequence of connected filters, each one
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connected to the previous one in the sequence. A filterchain is
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represented by a list of ","-separated filter descriptions.
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A filtergraph consists of a sequence of filterchains. A sequence of
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filterchains is represented by a list of ";"-separated filterchain
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descriptions.
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A filter is represented by a string of the form:
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[@var{in_link_1}]...[@var{in_link_N}]@var{filter_name}=@var{arguments}[@var{out_link_1}]...[@var{out_link_M}]
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@var{filter_name} is the name of the filter class of which the
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described filter is an instance of, and has to be the name of one of
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the filter classes registered in the program.
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The name of the filter class is optionally followed by a string
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"=@var{arguments}".
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@var{arguments} is a string which contains the parameters used to
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initialize the filter instance, and are described in the filter
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descriptions below.
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The list of arguments can be quoted using the character "'" as initial
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and ending mark, and the character '\' for escaping the characters
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within the quoted text; otherwise the argument string is considered
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terminated when the next special character (belonging to the set
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"[]=;,") is encountered.
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The name and arguments of the filter are optionally preceded and
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followed by a list of link labels.
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A link label allows to name a link and associate it to a filter output
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or input pad. The preceding labels @var{in_link_1}
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... @var{in_link_N}, are associated to the filter input pads,
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the following labels @var{out_link_1} ... @var{out_link_M}, are
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associated to the output pads.
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When two link labels with the same name are found in the
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filtergraph, a link between the corresponding input and output pad is
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created.
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If an output pad is not labelled, it is linked by default to the first
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unlabelled input pad of the next filter in the filterchain.
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For example in the filterchain:
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@example
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nullsrc, split[L1], [L2]overlay, nullsink
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@end example
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the split filter instance has two output pads, and the overlay filter
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instance two input pads. The first output pad of split is labelled
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"L1", the first input pad of overlay is labelled "L2", and the second
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output pad of split is linked to the second input pad of overlay,
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which are both unlabelled.
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In a complete filterchain all the unlabelled filter input and output
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pads must be connected. A filtergraph is considered valid if all the
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filter input and output pads of all the filterchains are connected.
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Libavfilter will automatically insert scale filters where format
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conversion is required. It is possible to specify swscale flags
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for those automatically inserted scalers by prepending
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@code{sws_flags=@var{flags};}
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to the filtergraph description.
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Follows a BNF description for the filtergraph syntax:
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@example
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@var{NAME} ::= sequence of alphanumeric characters and '_'
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@var{LINKLABEL} ::= "[" @var{NAME} "]"
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@var{LINKLABELS} ::= @var{LINKLABEL} [@var{LINKLABELS}]
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@var{FILTER_ARGUMENTS} ::= sequence of chars (eventually quoted)
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@var{FILTER} ::= [@var{LINKNAMES}] @var{NAME} ["=" @var{ARGUMENTS}] [@var{LINKNAMES}]
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@var{FILTERCHAIN} ::= @var{FILTER} [,@var{FILTERCHAIN}]
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@var{FILTERGRAPH} ::= [sws_flags=@var{flags};] @var{FILTERCHAIN} [;@var{FILTERGRAPH}]
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@end example
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@c man end FILTERGRAPH DESCRIPTION
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@chapter Audio Filters
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@c man begin AUDIO FILTERS
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When you configure your Libav build, you can disable any of the
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existing filters using --disable-filters.
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The configure output will show the audio filters included in your
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build.
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Below is a description of the currently available audio filters.
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@section aformat
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Convert the input audio to one of the specified formats. The framework will
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negotiate the most appropriate format to minimize conversions.
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The filter accepts the following named parameters:
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@table @option
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@item sample_fmts
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A comma-separated list of requested sample formats.
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@item sample_rates
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A comma-separated list of requested sample rates.
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@item channel_layouts
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A comma-separated list of requested channel layouts.
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@end table
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If a parameter is omitted, all values are allowed.
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For example to force the output to either unsigned 8-bit or signed 16-bit stereo:
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@example
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aformat=sample_fmts\=u8\,s16:channel_layouts\=stereo
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@end example
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@section amix
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Mixes multiple audio inputs into a single output.
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For example
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@example
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avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex amix=inputs=3:duration=first:dropout_transition=3 OUTPUT
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@end example
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will mix 3 input audio streams to a single output with the same duration as the
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first input and a dropout transition time of 3 seconds.
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The filter accepts the following named parameters:
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@table @option
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@item inputs
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Number of inputs. If unspecified, it defaults to 2.
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@item duration
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How to determine the end-of-stream.
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@table @option
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@item longest
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Duration of longest input. (default)
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@item shortest
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Duration of shortest input.
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@item first
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Duration of first input.
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@end table
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@item dropout_transition
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Transition time, in seconds, for volume renormalization when an input
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stream ends. The default value is 2 seconds.
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@end table
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@section anull
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Pass the audio source unchanged to the output.
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@section ashowinfo
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Show a line containing various information for each input audio frame.
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The input audio is not modified.
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The shown line contains a sequence of key/value pairs of the form
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@var{key}:@var{value}.
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A description of each shown parameter follows:
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@table @option
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@item n
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sequential number of the input frame, starting from 0
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@item pts
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Presentation timestamp of the input frame, in time base units; the time base
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depends on the filter input pad, and is usually 1/@var{sample_rate}.
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@item pts_time
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presentation timestamp of the input frame in seconds
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@item fmt
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sample format
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@item chlayout
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channel layout
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@item rate
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sample rate for the audio frame
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@item nb_samples
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number of samples (per channel) in the frame
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@item checksum
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Adler-32 checksum (printed in hexadecimal) of the audio data. For planar audio
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the data is treated as if all the planes were concatenated.
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@item plane_checksums
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A list of Adler-32 checksums for each data plane.
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@end table
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@section asplit
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Split input audio into several identical outputs.
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The filter accepts a single parameter which specifies the number of outputs. If
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unspecified, it defaults to 2.
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For example
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@example
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avconv -i INPUT -filter_complex asplit=5 OUTPUT
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@end example
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will create 5 copies of the input audio.
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@section asyncts
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Synchronize audio data with timestamps by squeezing/stretching it and/or
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dropping samples/adding silence when needed.
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The filter accepts the following named parameters:
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@table @option
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@item compensate
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Enable stretching/squeezing the data to make it match the timestamps. Disabled
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by default. When disabled, time gaps are covered with silence.
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@item min_delta
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Minimum difference between timestamps and audio data (in seconds) to trigger
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adding/dropping samples. Default value is 0.1. If you get non-perfect sync with
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this filter, try setting this parameter to 0.
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@item max_comp
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Maximum compensation in samples per second. Relevant only with compensate=1.
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Default value 500.
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@item first_pts
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Assume the first pts should be this value.
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This allows for padding/trimming at the start of stream. By default, no
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assumption is made about the first frame's expected pts, so no padding or
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trimming is done. For example, this could be set to 0 to pad the beginning with
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silence if an audio stream starts after the video stream.
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@end table
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@section channelsplit
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Split each channel in input audio stream into a separate output stream.
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This filter accepts the following named parameters:
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@table @option
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@item channel_layout
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Channel layout of the input stream. Default is "stereo".
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@end table
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For example, assuming a stereo input MP3 file
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@example
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avconv -i in.mp3 -filter_complex channelsplit out.mkv
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@end example
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will create an output Matroska file with two audio streams, one containing only
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the left channel and the other the right channel.
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To split a 5.1 WAV file into per-channel files
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@example
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avconv -i in.wav -filter_complex
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'channelsplit=channel_layout=5.1[FL][FR][FC][LFE][SL][SR]'
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-map '[FL]' front_left.wav -map '[FR]' front_right.wav -map '[FC]'
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front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
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side_right.wav
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@end example
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@section channelmap
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Remap input channels to new locations.
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This filter accepts the following named parameters:
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@table @option
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@item channel_layout
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Channel layout of the output stream.
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@item map
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Map channels from input to output. The argument is a comma-separated list of
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mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
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@var{in_channel} form. @var{in_channel} can be either the name of the input
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channel (e.g. FL for front left) or its index in the input channel layout.
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@var{out_channel} is the name of the output channel or its index in the output
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channel layout. If @var{out_channel} is not given then it is implicitly an
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index, starting with zero and increasing by one for each mapping.
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@end table
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If no mapping is present, the filter will implicitly map input channels to
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output channels preserving index.
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For example, assuming a 5.1+downmix input MOV file
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@example
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avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
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@end example
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will create an output WAV file tagged as stereo from the downmix channels of
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the input.
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To fix a 5.1 WAV improperly encoded in AAC's native channel order
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@example
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avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
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@end example
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@section join
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Join multiple input streams into one multi-channel stream.
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The filter accepts the following named parameters:
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@table @option
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@item inputs
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Number of input streams. Defaults to 2.
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@item channel_layout
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Desired output channel layout. Defaults to stereo.
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@item map
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Map channels from inputs to output. The argument is a comma-separated list of
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mappings, each in the @code{@var{input_idx}.@var{in_channel}-@var{out_channel}}
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form. @var{input_idx} is the 0-based index of the input stream. @var{in_channel}
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can be either the name of the input channel (e.g. FL for front left) or its
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index in the specified input stream. @var{out_channel} is the name of the output
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channel.
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@end table
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The filter will attempt to guess the mappings when those are not specified
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explicitly. It does so by first trying to find an unused matching input channel
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and if that fails it picks the first unused input channel.
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E.g. to join 3 inputs (with properly set channel layouts)
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@example
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avconv -i INPUT1 -i INPUT2 -i INPUT3 -filter_complex join=inputs=3 OUTPUT
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@end example
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To build a 5.1 output from 6 single-channel streams:
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@example
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avconv -i fl -i fr -i fc -i sl -i sr -i lfe -filter_complex
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'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'
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out
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@end example
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@section resample
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Convert the audio sample format, sample rate and channel layout. This filter is
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not meant to be used directly, it is inserted automatically by libavfilter
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whenever conversion is needed. Use the @var{aformat} filter to force a specific
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conversion.
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@c man end AUDIO FILTERS
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@chapter Audio Sources
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@c man begin AUDIO SOURCES
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Below is a description of the currently available audio sources.
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@section anullsrc
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Null audio source, never return audio frames. It is mainly useful as a
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template and to be employed in analysis / debugging tools.
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It accepts as optional parameter a string of the form
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@var{sample_rate}:@var{channel_layout}.
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@var{sample_rate} specify the sample rate, and defaults to 44100.
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@var{channel_layout} specify the channel layout, and can be either an
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integer or a string representing a channel layout. The default value
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of @var{channel_layout} is 3, which corresponds to CH_LAYOUT_STEREO.
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Check the channel_layout_map definition in
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@file{libavutil/channel_layout.c} for the mapping between strings and
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channel layout values.
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Follow some examples:
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@example
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# set the sample rate to 48000 Hz and the channel layout to CH_LAYOUT_MONO.
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anullsrc=48000:4
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# same as
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anullsrc=48000:mono
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@end example
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@section abuffer
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Buffer audio frames, and make them available to the filter chain.
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This source is not intended to be part of user-supplied graph descriptions but
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for insertion by calling programs through the interface defined in
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@file{libavfilter/buffersrc.h}.
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It accepts the following named parameters:
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@table @option
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@item time_base
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Timebase which will be used for timestamps of submitted frames. It must be
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either a floating-point number or in @var{numerator}/@var{denominator} form.
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@item sample_rate
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Audio sample rate.
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@item sample_fmt
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Name of the sample format, as returned by @code{av_get_sample_fmt_name()}.
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@item channel_layout
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Channel layout of the audio data, in the form that can be accepted by
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@code{av_get_channel_layout()}.
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@end table
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All the parameters need to be explicitly defined.
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@c man end AUDIO SOURCES
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@chapter Audio Sinks
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@c man begin AUDIO SINKS
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Below is a description of the currently available audio sinks.
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@section anullsink
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Null audio sink, do absolutely nothing with the input audio. It is
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mainly useful as a template and to be employed in analysis / debugging
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tools.
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@section abuffersink
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This sink is intended for programmatic use. Frames that arrive on this sink can
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be retrieved by the calling program using the interface defined in
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@file{libavfilter/buffersink.h}.
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This filter accepts no parameters.
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@c man end AUDIO SINKS
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@chapter Video Filters
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@c man begin VIDEO FILTERS
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When you configure your Libav build, you can disable any of the
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existing filters using --disable-filters.
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The configure output will show the video filters included in your
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build.
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Below is a description of the currently available video filters.
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@section blackframe
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Detect frames that are (almost) completely black. Can be useful to
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detect chapter transitions or commercials. Output lines consist of
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the frame number of the detected frame, the percentage of blackness,
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the position in the file if known or -1 and the timestamp in seconds.
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In order to display the output lines, you need to set the loglevel at
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least to the AV_LOG_INFO value.
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The filter accepts the syntax:
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@example
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blackframe[=@var{amount}:[@var{threshold}]]
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@end example
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@var{amount} is the percentage of the pixels that have to be below the
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threshold, and defaults to 98.
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@var{threshold} is the threshold below which a pixel value is
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considered black, and defaults to 32.
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@section boxblur
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Apply boxblur algorithm to the input video.
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This filter accepts the parameters:
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@var{luma_power}:@var{luma_radius}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
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Chroma and alpha parameters are optional, if not specified they default
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to the corresponding values set for @var{luma_radius} and
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@var{luma_power}.
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@var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
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the radius in pixels of the box used for blurring the corresponding
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input plane. They are expressions, and can contain the following
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constants:
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@table @option
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@item w, h
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the input width and height in pixels
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@item cw, ch
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the input chroma image width and height in pixels
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@item hsub, vsub
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horizontal and vertical chroma subsample values. For example for the
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pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
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@end table
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The radius must be a non-negative number, and must not be greater than
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the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
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and of @code{min(cw,ch)/2} for the chroma planes.
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@var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
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how many times the boxblur filter is applied to the corresponding
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plane.
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Some examples follow:
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@itemize
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@item
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Apply a boxblur filter with luma, chroma, and alpha radius
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set to 2:
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@example
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boxblur=2:1
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@end example
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@item
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Set luma radius to 2, alpha and chroma radius to 0
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@example
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boxblur=2:1:0:0:0:0
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@end example
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@item
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Set luma and chroma radius to a fraction of the video dimension
|
|
@example
|
|
boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section copy
|
|
|
|
Copy the input source unchanged to the output. Mainly useful for
|
|
testing purposes.
|
|
|
|
@section crop
|
|
|
|
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
|
|
|
|
The 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 x, y
|
|
the computed values for @var{x} and @var{y}. They are evaluated for
|
|
each new frame.
|
|
|
|
@item in_w, in_h
|
|
the input width and height
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output (cropped) width and height
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item n
|
|
the number of input frame, starting from 0
|
|
|
|
@item pos
|
|
the position in the file of the input frame, NAN if unknown
|
|
|
|
@item t
|
|
timestamp expressed in seconds, NAN if the input timestamp is unknown
|
|
|
|
@end table
|
|
|
|
The @var{out_w} and @var{out_h} parameters specify the expressions for
|
|
the width and height of the output (cropped) video. They are
|
|
evaluated just at the configuration of the filter.
|
|
|
|
The default value of @var{out_w} is "in_w", and the default value of
|
|
@var{out_h} is "in_h".
|
|
|
|
The expression for @var{out_w} may depend on the value of @var{out_h},
|
|
and the expression for @var{out_h} may depend on @var{out_w}, but they
|
|
cannot depend on @var{x} and @var{y}, as @var{x} and @var{y} are
|
|
evaluated after @var{out_w} and @var{out_h}.
|
|
|
|
The @var{x} and @var{y} parameters specify the expressions for the
|
|
position of the top-left corner of the output (non-cropped) area. They
|
|
are evaluated for each frame. If the evaluated value is not valid, it
|
|
is approximated to the nearest valid value.
|
|
|
|
The default value of @var{x} is "(in_w-out_w)/2", and the default
|
|
value for @var{y} is "(in_h-out_h)/2", which set the cropped area at
|
|
the center of the input image.
|
|
|
|
The expression for @var{x} may depend on @var{y}, and the expression
|
|
for @var{y} may depend on @var{x}.
|
|
|
|
Follow some examples:
|
|
@example
|
|
# crop the central input area with size 100x100
|
|
crop=100:100
|
|
|
|
# crop the central input area with size 2/3 of the input video
|
|
"crop=2/3*in_w:2/3*in_h"
|
|
|
|
# crop the input video central square
|
|
crop=in_h
|
|
|
|
# delimit the rectangle with the top-left corner placed at position
|
|
# 100:100 and the right-bottom corner corresponding to the right-bottom
|
|
# corner of the input image.
|
|
crop=in_w-100:in_h-100:100:100
|
|
|
|
# crop 10 pixels from the left and right borders, and 20 pixels from
|
|
# the top and bottom borders
|
|
"crop=in_w-2*10:in_h-2*20"
|
|
|
|
# keep only the bottom right quarter of the input image
|
|
"crop=in_w/2:in_h/2:in_w/2:in_h/2"
|
|
|
|
# crop height for getting Greek harmony
|
|
"crop=in_w:1/PHI*in_w"
|
|
|
|
# trembling effect
|
|
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(n/10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(n/7)"
|
|
|
|
# erratic camera effect depending on timestamp
|
|
"crop=in_w/2:in_h/2:(in_w-out_w)/2+((in_w-out_w)/2)*sin(t*10):(in_h-out_h)/2 +((in_h-out_h)/2)*sin(t*13)"
|
|
|
|
# set x depending on the value of y
|
|
"crop=in_w/2:in_h/2:y:10+10*sin(n/10)"
|
|
@end example
|
|
|
|
@section cropdetect
|
|
|
|
Auto-detect crop size.
|
|
|
|
Calculate necessary cropping parameters and prints the recommended
|
|
parameters through the logging system. The detected dimensions
|
|
correspond to the non-black area of the input video.
|
|
|
|
It accepts the syntax:
|
|
@example
|
|
cropdetect[=@var{limit}[:@var{round}[:@var{reset}]]]
|
|
@end example
|
|
|
|
@table @option
|
|
|
|
@item limit
|
|
Threshold, which can be optionally specified from nothing (0) to
|
|
everything (255), defaults to 24.
|
|
|
|
@item round
|
|
Value which the width/height should be divisible by, defaults to
|
|
16. The offset is automatically adjusted to center the video. Use 2 to
|
|
get only even dimensions (needed for 4:2:2 video). 16 is best when
|
|
encoding to most video codecs.
|
|
|
|
@item reset
|
|
Counter that determines after how many frames cropdetect will reset
|
|
the previously detected largest video area and start over to detect
|
|
the current optimal crop area. Defaults to 0.
|
|
|
|
This can be useful when channel logos distort the video area. 0
|
|
indicates never reset and return the largest area encountered during
|
|
playback.
|
|
@end table
|
|
|
|
@section delogo
|
|
|
|
Suppress a TV station logo by a simple interpolation of the surrounding
|
|
pixels. Just set a rectangle covering the logo and watch it disappear
|
|
(and sometimes something even uglier appear - your mileage may vary).
|
|
|
|
The filter accepts parameters as a string of the form
|
|
"@var{x}:@var{y}:@var{w}:@var{h}:@var{band}", or as a list of
|
|
@var{key}=@var{value} pairs, separated by ":".
|
|
|
|
The description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
|
|
@item x, y
|
|
Specify the top left corner coordinates of the logo. They must be
|
|
specified.
|
|
|
|
@item w, h
|
|
Specify the width and height of the logo to clear. They must be
|
|
specified.
|
|
|
|
@item band, t
|
|
Specify the thickness of the fuzzy edge of the rectangle (added to
|
|
@var{w} and @var{h}). The default value is 4.
|
|
|
|
@item show
|
|
When set to 1, a green rectangle is drawn on the screen to simplify
|
|
finding the right @var{x}, @var{y}, @var{w}, @var{h} parameters, and
|
|
@var{band} is set to 4. The default value is 0.
|
|
|
|
@end table
|
|
|
|
Some examples follow.
|
|
|
|
@itemize
|
|
|
|
@item
|
|
Set a rectangle covering the area with top left corner coordinates 0,0
|
|
and size 100x77, setting a band of size 10:
|
|
@example
|
|
delogo=0:0:100:77:10
|
|
@end example
|
|
|
|
@item
|
|
As the previous example, but use named options:
|
|
@example
|
|
delogo=x=0:y=0:w=100:h=77:band=10
|
|
@end example
|
|
|
|
@end itemize
|
|
|
|
@section drawbox
|
|
|
|
Draw a colored box on the input image.
|
|
|
|
It accepts the syntax:
|
|
@example
|
|
drawbox=@var{x}:@var{y}:@var{width}:@var{height}:@var{color}
|
|
@end example
|
|
|
|
@table @option
|
|
|
|
@item x, y
|
|
Specify the top left corner coordinates of the box. Default to 0.
|
|
|
|
@item width, height
|
|
Specify the width and height of the box, if 0 they are interpreted as
|
|
the input width and height. Default to 0.
|
|
|
|
@item color
|
|
Specify the color of the box to write, it can be the name of a color
|
|
(case insensitive match) or a 0xRRGGBB[AA] sequence.
|
|
@end table
|
|
|
|
Follow some examples:
|
|
@example
|
|
# draw a black box around the edge of the input image
|
|
drawbox
|
|
|
|
# draw a box with color red and an opacity of 50%
|
|
drawbox=10:20:200:60:red@@0.5"
|
|
@end example
|
|
|
|
@section drawtext
|
|
|
|
Draw text string or text from specified file on top of video using the
|
|
libfreetype library.
|
|
|
|
To enable compilation of this filter you need to configure Libav with
|
|
@code{--enable-libfreetype}.
|
|
|
|
The filter also recognizes strftime() sequences in the provided text
|
|
and expands them accordingly. Check the documentation of strftime().
|
|
|
|
The filter accepts parameters as a list of @var{key}=@var{value} pairs,
|
|
separated by ":".
|
|
|
|
The description of the accepted parameters follows.
|
|
|
|
@table @option
|
|
|
|
@item 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 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 t
|
|
timestamp expressed in seconds, NAN if the input timestamp is unknown
|
|
|
|
@end table
|
|
|
|
The default value of @var{x} and @var{y} is 0.
|
|
|
|
@item fontsize
|
|
The font size to be used for drawing text.
|
|
The default value of @var{fontsize} is 16.
|
|
|
|
@item fontcolor
|
|
The color to be used for drawing fonts.
|
|
Either a string (e.g. "red") or in 0xRRGGBB[AA] format
|
|
(e.g. "0xff000033"), possibly followed by an alpha specifier.
|
|
The default value of @var{fontcolor} is "black".
|
|
|
|
@item 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 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 ft_load_flags
|
|
Flags to be used for loading the fonts.
|
|
|
|
The flags map the corresponding flags supported by libfreetype, and are
|
|
a combination of the following values:
|
|
@table @var
|
|
@item default
|
|
@item no_scale
|
|
@item no_hinting
|
|
@item render
|
|
@item no_bitmap
|
|
@item vertical_layout
|
|
@item force_autohint
|
|
@item crop_bitmap
|
|
@item pedantic
|
|
@item ignore_global_advance_width
|
|
@item no_recurse
|
|
@item ignore_transform
|
|
@item monochrome
|
|
@item linear_design
|
|
@item no_autohint
|
|
@item end table
|
|
@end table
|
|
|
|
Default value is "render".
|
|
|
|
For more information consult the documentation for the FT_LOAD_*
|
|
libfreetype flags.
|
|
|
|
@item 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.
|
|
@end table
|
|
|
|
For example the command:
|
|
@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.
|
|
|
|
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.
|
|
|
|
For more information about libfreetype, check:
|
|
@url{http://www.freetype.org/}.
|
|
|
|
@section fade
|
|
|
|
Apply fade-in/out effect to input video.
|
|
|
|
It accepts the parameters:
|
|
@var{type}:@var{start_frame}:@var{nb_frames}
|
|
|
|
@var{type} specifies if the effect type, can be either "in" for
|
|
fade-in, or "out" for a fade-out effect.
|
|
|
|
@var{start_frame} specifies the number of the start frame for starting
|
|
to apply the fade effect.
|
|
|
|
@var{nb_frames} specifies the number of frames for which the fade
|
|
effect has to last. At the end of the fade-in effect the output video
|
|
will have the same intensity as the input video, at the end of the
|
|
fade-out transition the output video will be completely black.
|
|
|
|
A few usage examples follow, usable too as test scenarios.
|
|
@example
|
|
# fade in first 30 frames of video
|
|
fade=in:0:30
|
|
|
|
# fade out last 45 frames of a 200-frame video
|
|
fade=out:155:45
|
|
|
|
# fade in first 25 frames and fade out last 25 frames of a 1000-frame video
|
|
fade=in:0:25, fade=out:975:25
|
|
|
|
# make first 5 frames black, then fade in from frame 5-24
|
|
fade=in:5:20
|
|
@end example
|
|
|
|
@section fieldorder
|
|
|
|
Transform the field order of the input video.
|
|
|
|
It accepts one parameter which specifies the required field order that
|
|
the input interlaced video will be transformed to. The parameter can
|
|
assume one of the following values:
|
|
|
|
@table @option
|
|
@item 0 or bff
|
|
output bottom field first
|
|
@item 1 or tff
|
|
output top field first
|
|
@end table
|
|
|
|
Default value is "tff".
|
|
|
|
Transformation is achieved by shifting the picture content up or down
|
|
by one line, and filling the remaining line with appropriate picture content.
|
|
This method is consistent with most broadcast field order converters.
|
|
|
|
If the input video is not flagged as being interlaced, or it is already
|
|
flagged as being of the required output field order then this filter does
|
|
not alter the incoming video.
|
|
|
|
This filter is very useful when converting to or from PAL DV material,
|
|
which is bottom field first.
|
|
|
|
For example:
|
|
@example
|
|
./avconv -i in.vob -vf "fieldorder=bff" out.dv
|
|
@end example
|
|
|
|
@section fifo
|
|
|
|
Buffer input images and send them when they are requested.
|
|
|
|
This filter is mainly useful when auto-inserted by the libavfilter
|
|
framework.
|
|
|
|
The filter does not take parameters.
|
|
|
|
@section format
|
|
|
|
Convert the input video to one of the specified pixel formats.
|
|
Libavfilter will try to pick one that is supported for the input to
|
|
the next filter.
|
|
|
|
The filter accepts a list of pixel format names, separated by ":",
|
|
for example "yuv420p:monow:rgb24".
|
|
|
|
Some examples follow:
|
|
@example
|
|
# convert the input video to the format "yuv420p"
|
|
format=yuv420p
|
|
|
|
# convert the input video to any of the formats in the list
|
|
format=yuv420p:yuv444p:yuv410p
|
|
@end example
|
|
|
|
@section fps
|
|
|
|
Convert the video to specified constant framerate by duplicating or dropping
|
|
frames as necessary.
|
|
|
|
This filter accepts the following named parameters:
|
|
@table @option
|
|
|
|
@item fps
|
|
Desired output framerate.
|
|
|
|
@end table
|
|
|
|
@anchor{frei0r}
|
|
@section frei0r
|
|
|
|
Apply a frei0r effect to the input video.
|
|
|
|
To enable compilation of this filter you need to install the frei0r
|
|
header and configure Libav with --enable-frei0r.
|
|
|
|
The filter supports the syntax:
|
|
@example
|
|
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
|
|
@end example
|
|
|
|
@var{filter_name} is the name to the frei0r effect to load. If the
|
|
environment variable @env{FREI0R_PATH} is defined, the frei0r effect
|
|
is searched in each one of the directories specified by the colon
|
|
separated list in @env{FREIOR_PATH}, otherwise in the standard frei0r
|
|
paths, which are in this order: @file{HOME/.frei0r-1/lib/},
|
|
@file{/usr/local/lib/frei0r-1/}, @file{/usr/lib/frei0r-1/}.
|
|
|
|
@var{param1}, @var{param2}, ... , @var{paramN} specify the parameters
|
|
for the frei0r effect.
|
|
|
|
A frei0r effect parameter can be a boolean (whose values are specified
|
|
with "y" and "n"), a double, a color (specified by the syntax
|
|
@var{R}/@var{G}/@var{B}, @var{R}, @var{G}, and @var{B} being float
|
|
numbers from 0.0 to 1.0) or by an @code{av_parse_color()} color
|
|
description), a position (specified by the syntax @var{X}/@var{Y},
|
|
@var{X} and @var{Y} being float numbers) and a string.
|
|
|
|
The number and kind of parameters depend on the loaded effect. If an
|
|
effect parameter is not specified the default value is set.
|
|
|
|
Some examples follow:
|
|
@example
|
|
# apply the distort0r effect, set the first two double parameters
|
|
frei0r=distort0r:0.5:0.01
|
|
|
|
# apply the colordistance effect, takes a color as first parameter
|
|
frei0r=colordistance:0.2/0.3/0.4
|
|
frei0r=colordistance:violet
|
|
frei0r=colordistance:0x112233
|
|
|
|
# apply the perspective effect, specify the top left and top right
|
|
# image positions
|
|
frei0r=perspective:0.2/0.2:0.8/0.2
|
|
@end example
|
|
|
|
For more information see:
|
|
@url{http://piksel.org/frei0r}
|
|
|
|
@section gradfun
|
|
|
|
Fix the banding artifacts that are sometimes introduced into nearly flat
|
|
regions by truncation to 8bit colordepth.
|
|
Interpolate the gradients that should go where the bands are, and
|
|
dither them.
|
|
|
|
This filter is designed for playback only. Do not use it prior to
|
|
lossy compression, because compression tends to lose the dither and
|
|
bring back the bands.
|
|
|
|
The filter takes two optional parameters, separated by ':':
|
|
@var{strength}:@var{radius}
|
|
|
|
@var{strength} is the maximum amount by which the filter will change
|
|
any one pixel. Also the threshold for detecting nearly flat
|
|
regions. Acceptable values range from .51 to 255, default value is
|
|
1.2, out-of-range values will be clipped to the valid range.
|
|
|
|
@var{radius} is the neighborhood to fit the gradient to. A larger
|
|
radius makes for smoother gradients, but also prevents the filter from
|
|
modifying the pixels near detailed regions. Acceptable values are
|
|
8-32, default value is 16, out-of-range values will be clipped to the
|
|
valid range.
|
|
|
|
@example
|
|
# default parameters
|
|
gradfun=1.2:16
|
|
|
|
# omitting radius
|
|
gradfun=1.2
|
|
@end example
|
|
|
|
@section hflip
|
|
|
|
Flip the input video horizontally.
|
|
|
|
For example to horizontally flip the input video with @command{avconv}:
|
|
@example
|
|
avconv -i in.avi -vf "hflip" out.avi
|
|
@end example
|
|
|
|
@section hqdn3d
|
|
|
|
High precision/quality 3d denoise filter. This filter aims to reduce
|
|
image noise producing smooth images and making still images really
|
|
still. It should enhance compressibility.
|
|
|
|
It accepts the following optional parameters:
|
|
@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
|
|
|
|
@table @option
|
|
@item luma_spatial
|
|
a non-negative float number which specifies spatial luma strength,
|
|
defaults to 4.0
|
|
|
|
@item chroma_spatial
|
|
a non-negative float number which specifies spatial chroma strength,
|
|
defaults to 3.0*@var{luma_spatial}/4.0
|
|
|
|
@item luma_tmp
|
|
a float number which specifies luma temporal strength, defaults to
|
|
6.0*@var{luma_spatial}/4.0
|
|
|
|
@item chroma_tmp
|
|
a float number which specifies chroma temporal strength, defaults to
|
|
@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
|
|
@end table
|
|
|
|
@section 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 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 val
|
|
input value for the pixel component
|
|
|
|
@item clipval
|
|
the input value clipped in the @var{minval}-@var{maxval} range
|
|
|
|
@item maxval
|
|
maximum value for the pixel component
|
|
|
|
@item minval
|
|
minimum value for the pixel component
|
|
|
|
@item negval
|
|
the negated value for the pixel component value clipped in the
|
|
@var{minval}-@var{maxval} range , it corresponds to the expression
|
|
"maxval-clipval+minval"
|
|
|
|
@item clip(val)
|
|
the computed value in @var{val} clipped in the
|
|
@var{minval}-@var{maxval} range
|
|
|
|
@item gammaval(gamma)
|
|
the computed gamma correction value of the pixel component value
|
|
clipped in the @var{minval}-@var{maxval} range, corresponds to the
|
|
expression
|
|
"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
|
|
|
|
@end table
|
|
|
|
All expressions default to "val".
|
|
|
|
Some examples follow:
|
|
@example
|
|
# negate input video
|
|
lutrgb="r=maxval+minval-val:g=maxval+minval-val:b=maxval+minval-val"
|
|
lutyuv="y=maxval+minval-val:u=maxval+minval-val:v=maxval+minval-val"
|
|
|
|
# the above is the same as
|
|
lutrgb="r=negval:g=negval:b=negval"
|
|
lutyuv="y=negval:u=negval:v=negval"
|
|
|
|
# negate luminance
|
|
lutyuv=negval
|
|
|
|
# remove chroma components, turns the video into a graytone image
|
|
lutyuv="u=128:v=128"
|
|
|
|
# apply a luma burning effect
|
|
lutyuv="y=2*val"
|
|
|
|
# remove green and blue components
|
|
lutrgb="g=0:b=0"
|
|
|
|
# set a constant alpha channel value on input
|
|
format=rgba,lutrgb=a="maxval-minval/2"
|
|
|
|
# correct luminance gamma by a 0.5 factor
|
|
lutyuv=y=gammaval(0.5)
|
|
@end example
|
|
|
|
@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.
|
|
|
|
Force libavfilter not to use any of the specified pixel formats for the
|
|
input to the next filter.
|
|
|
|
The filter accepts a list of pixel format names, separated by ":",
|
|
for example "yuv420p:monow:rgb24".
|
|
|
|
Some examples follow:
|
|
@example
|
|
# force libavfilter to use a format different from "yuv420p" for the
|
|
# input to the vflip filter
|
|
noformat=yuv420p,vflip
|
|
|
|
# convert the input video to any of the formats not contained in the list
|
|
noformat=yuv420p:yuv444p:yuv410p
|
|
@end example
|
|
|
|
@section null
|
|
|
|
Pass the video source unchanged to the output.
|
|
|
|
@section ocv
|
|
|
|
Apply video transform using libopencv.
|
|
|
|
To enable this filter install libopencv library and headers and
|
|
configure Libav with --enable-libopencv.
|
|
|
|
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
|
|
|
|
@var{filter_name} is the name of the libopencv filter to apply.
|
|
|
|
@var{filter_params} specifies the parameters to pass to the libopencv
|
|
filter. If not specified the default values are assumed.
|
|
|
|
Refer to the official libopencv documentation for more precise
|
|
information:
|
|
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
|
|
|
|
Follows the list of supported libopencv filters.
|
|
|
|
@anchor{dilate}
|
|
@subsection dilate
|
|
|
|
Dilate an image by using a specific structuring element.
|
|
This filter corresponds to the libopencv function @code{cvDilate}.
|
|
|
|
It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
|
|
|
|
@var{struct_el} represents a structuring element, and has the syntax:
|
|
@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
|
|
|
|
@var{cols} and @var{rows} represent the number of columns and rows of
|
|
the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
|
|
point, and @var{shape} the shape for the structuring element, and
|
|
can be one of the values "rect", "cross", "ellipse", "custom".
|
|
|
|
If the value for @var{shape} is "custom", it must be followed by a
|
|
string of the form "=@var{filename}". The file with name
|
|
@var{filename} is assumed to represent a binary image, with each
|
|
printable character corresponding to a bright pixel. When a custom
|
|
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
|
|
or columns and rows of the read file are assumed instead.
|
|
|
|
The default value for @var{struct_el} is "3x3+0x0/rect".
|
|
|
|
@var{nb_iterations} specifies the number of times the transform is
|
|
applied to the image, and defaults to 1.
|
|
|
|
Follow some example:
|
|
@example
|
|
# use the default values
|
|
ocv=dilate
|
|
|
|
# dilate using a structuring element with a 5x5 cross, iterate two times
|
|
ocv=dilate=5x5+2x2/cross:2
|
|
|
|
# read the shape from the file diamond.shape, iterate two times
|
|
# the file diamond.shape may contain a pattern of characters like this:
|
|
# *
|
|
# ***
|
|
# *****
|
|
# ***
|
|
# *
|
|
# the specified cols and rows are ignored (but not the anchor point coordinates)
|
|
ocv=0x0+2x2/custom=diamond.shape:2
|
|
@end example
|
|
|
|
@subsection erode
|
|
|
|
Erode an image by using a specific structuring element.
|
|
This filter corresponds to the libopencv function @code{cvErode}.
|
|
|
|
The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
|
|
with the same syntax and semantics as the @ref{dilate} filter.
|
|
|
|
@subsection smooth
|
|
|
|
Smooth the input video.
|
|
|
|
The filter takes the following parameters:
|
|
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
|
|
|
|
@var{type} is the type of smooth filter to apply, and can be one of
|
|
the following values: "blur", "blur_no_scale", "median", "gaussian",
|
|
"bilateral". The default value is "gaussian".
|
|
|
|
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
|
|
parameters whose meanings depend on smooth type. @var{param1} and
|
|
@var{param2} accept integer positive values or 0, @var{param3} and
|
|
@var{param4} accept float values.
|
|
|
|
The default value for @var{param1} is 3, the default value for the
|
|
other parameters is 0.
|
|
|
|
These parameters correspond to the parameters assigned to the
|
|
libopencv function @code{cvSmooth}.
|
|
|
|
@anchor{overlay}
|
|
@section overlay
|
|
|
|
Overlay one video on top of another.
|
|
|
|
It takes two inputs and one output, the first input is the "main"
|
|
video on which the second input is overlayed.
|
|
|
|
It accepts the parameters: @var{x}:@var{y}.
|
|
|
|
@var{x} is the x coordinate of the overlayed video on the main video,
|
|
@var{y} is the y coordinate. The parameters are expressions containing
|
|
the following parameters:
|
|
|
|
@table @option
|
|
@item main_w, main_h
|
|
main input width and height
|
|
|
|
@item W, H
|
|
same as @var{main_w} and @var{main_h}
|
|
|
|
@item overlay_w, overlay_h
|
|
overlay input width and height
|
|
|
|
@item w, h
|
|
same as @var{overlay_w} and @var{overlay_h}
|
|
@end table
|
|
|
|
Be aware that frames are taken from each input video in timestamp
|
|
order, hence, if their initial timestamps differ, it is a a good idea
|
|
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
|
|
have them begin in the same zero timestamp, as it does the example for
|
|
the @var{movie} filter.
|
|
|
|
Follow some examples:
|
|
@example
|
|
# draw the overlay at 10 pixels from the bottom right
|
|
# corner of the main video.
|
|
overlay=main_w-overlay_w-10:main_h-overlay_h-10
|
|
|
|
# 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
|
|
|
|
# insert 2 different transparent PNG logos (second logo on bottom
|
|
# right corner):
|
|
avconv -i input -i logo1 -i logo2 -filter_complex
|
|
'overlay=10:H-h-10,overlay=W-w-10:H-h-10' output
|
|
|
|
# add a transparent color layer on top of the main video,
|
|
# WxH specifies the size of the main input to the overlay filter
|
|
color=red@.3:WxH [over]; [in][over] overlay [out]
|
|
@end example
|
|
|
|
You can chain together more overlays but the efficiency of such
|
|
approach is yet to be tested.
|
|
|
|
@section pad
|
|
|
|
Add paddings to the input image, and places the original input at the
|
|
given coordinates @var{x}, @var{y}.
|
|
|
|
It accepts the following parameters:
|
|
@var{width}:@var{height}:@var{x}:@var{y}:@var{color}.
|
|
|
|
The parameters @var{width}, @var{height}, @var{x}, and @var{y} 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 video width and height
|
|
|
|
@item iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output width and height, that is the size of the padded area as
|
|
specified by the @var{width} and @var{height} expressions
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item x, y
|
|
x and y offsets as specified by the @var{x} and @var{y}
|
|
expressions, or NAN if not yet specified
|
|
|
|
@item a
|
|
input display aspect ratio, same as @var{iw} / @var{ih}
|
|
|
|
@item hsub, vsub
|
|
horizontal and vertical chroma subsample values. For example for the
|
|
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
|
@end table
|
|
|
|
Follows the description of the accepted parameters.
|
|
|
|
@table @option
|
|
@item width, height
|
|
|
|
Specify the size of the output image with the paddings added. If the
|
|
value for @var{width} or @var{height} is 0, the corresponding input size
|
|
is used for the output.
|
|
|
|
The @var{width} expression can reference the value set by the
|
|
@var{height} expression, and vice versa.
|
|
|
|
The default value of @var{width} and @var{height} is 0.
|
|
|
|
@item x, y
|
|
|
|
Specify the offsets where to place the input image in the padded area
|
|
with respect to the top/left border of the output image.
|
|
|
|
The @var{x} expression can reference the value set by the @var{y}
|
|
expression, and vice versa.
|
|
|
|
The default value of @var{x} and @var{y} is 0.
|
|
|
|
@item color
|
|
|
|
Specify the color of the padded area, it can be the name of a color
|
|
(case insensitive match) or a 0xRRGGBB[AA] sequence.
|
|
|
|
The default value of @var{color} is "black".
|
|
|
|
@end table
|
|
|
|
Some examples follow:
|
|
|
|
@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
|
|
|
|
# pad the input to get an output with dimensions increased bt 3/2,
|
|
# and put the input video at the center of the padded area
|
|
pad="3/2*iw:3/2*ih:(ow-iw)/2:(oh-ih)/2"
|
|
|
|
# pad the input to get a squared output with size equal to the maximum
|
|
# value between the input width and height, and put the input video at
|
|
# the center of the padded area
|
|
pad="max(iw\,ih):ow:(ow-iw)/2:(oh-ih)/2"
|
|
|
|
# pad the input to get a final w/h ratio of 16:9
|
|
pad="ih*16/9:ih:(ow-iw)/2:(oh-ih)/2"
|
|
|
|
# double output size and put the input video in the bottom-right
|
|
# corner of the output padded area
|
|
pad="2*iw:2*ih:ow-iw:oh-ih"
|
|
@end example
|
|
|
|
@section pixdesctest
|
|
|
|
Pixel format descriptor test filter, mainly useful for internal
|
|
testing. The output video should be equal to the input video.
|
|
|
|
For example:
|
|
@example
|
|
format=monow, pixdesctest
|
|
@end example
|
|
|
|
can be used to test the monowhite pixel format descriptor definition.
|
|
|
|
@section scale
|
|
|
|
Scale the input video to @var{width}:@var{height} and/or convert the image format.
|
|
|
|
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 iw, ih
|
|
same as @var{in_w} and @var{in_h}
|
|
|
|
@item out_w, out_h
|
|
the output (cropped) width and height
|
|
|
|
@item ow, oh
|
|
same as @var{out_w} and @var{out_h}
|
|
|
|
@item dar, a
|
|
input display aspect ratio, same as @var{iw} / @var{ih}
|
|
|
|
@item sar
|
|
input sample aspect ratio
|
|
|
|
@item hsub, vsub
|
|
horizontal and vertical chroma subsample values. For example for the
|
|
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
|
@end table
|
|
|
|
If the input image format is different from the format requested by
|
|
the next filter, the scale filter will convert the input to the
|
|
requested format.
|
|
|
|
If the value for @var{width} or @var{height} is 0, the respective input
|
|
size is used for the output.
|
|
|
|
If the value for @var{width} or @var{height} is -1, the scale filter will
|
|
use, for the respective output size, a value that maintains the aspect
|
|
ratio of the input image.
|
|
|
|
The default value of @var{width} and @var{height} is 0.
|
|
|
|
Some examples follow:
|
|
@example
|
|
# scale the input video to a size of 200x100.
|
|
scale=200:100
|
|
|
|
# scale the input to 2x
|
|
scale=2*iw:2*ih
|
|
# the above is the same as
|
|
scale=2*in_w:2*in_h
|
|
|
|
# scale the input to half size
|
|
scale=iw/2:ih/2
|
|
|
|
# increase the width, and set the height to the same size
|
|
scale=3/2*iw:ow
|
|
|
|
# seek for Greek harmony
|
|
scale=iw:1/PHI*iw
|
|
scale=ih*PHI:ih
|
|
|
|
# increase the height, and set the width to 3/2 of the height
|
|
scale=3/2*oh:3/5*ih
|
|
|
|
# increase the size, but make the size a multiple of the chroma
|
|
scale="trunc(3/2*iw/hsub)*hsub:trunc(3/2*ih/vsub)*vsub"
|
|
|
|
# increase the width to a maximum of 500 pixels, keep the same input aspect ratio
|
|
scale='min(500\, iw*3/2):-1'
|
|
@end example
|
|
|
|
@section select
|
|
Select frames to pass in output.
|
|
|
|
It accepts in input an expression, which is evaluated for each input
|
|
frame. If the expression is evaluated to a non-zero value, the frame
|
|
is selected and passed to the output, otherwise it is discarded.
|
|
|
|
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 selected_n
|
|
the sequential number of the selected frame, starting from 0
|
|
|
|
@item prev_selected_n
|
|
the sequential number of the last selected frame, NAN if undefined
|
|
|
|
@item TB
|
|
timebase of the input timestamps
|
|
|
|
@item pts
|
|
the PTS (Presentation TimeStamp) of the filtered video frame,
|
|
expressed in @var{TB} units, NAN if undefined
|
|
|
|
@item t
|
|
the PTS (Presentation TimeStamp) of the filtered video frame,
|
|
expressed in seconds, NAN if undefined
|
|
|
|
@item prev_pts
|
|
the PTS of the previously filtered video frame, NAN if undefined
|
|
|
|
@item prev_selected_pts
|
|
the PTS of the last previously filtered video frame, NAN if undefined
|
|
|
|
@item prev_selected_t
|
|
the PTS of the last previously selected video frame, NAN if undefined
|
|
|
|
@item start_pts
|
|
the PTS of the first video frame in the video, NAN if undefined
|
|
|
|
@item start_t
|
|
the time of the first video frame in the video, NAN if undefined
|
|
|
|
@item pict_type
|
|
the type of the filtered frame, can assume one of the following
|
|
values:
|
|
@table @option
|
|
@item I
|
|
@item P
|
|
@item B
|
|
@item S
|
|
@item SI
|
|
@item SP
|
|
@item BI
|
|
@end table
|
|
|
|
@item interlace_type
|
|
the frame interlace type, can assume one of the following values:
|
|
@table @option
|
|
@item PROGRESSIVE
|
|
the frame is progressive (not interlaced)
|
|
@item TOPFIRST
|
|
the frame is top-field-first
|
|
@item BOTTOMFIRST
|
|
the frame is bottom-field-first
|
|
@end table
|
|
|
|
@item key
|
|
1 if the filtered frame is a key-frame, 0 otherwise
|
|
|
|
@item pos
|
|
the position in the file of the filtered frame, -1 if the information
|
|
is not available (e.g. for synthetic video)
|
|
@end table
|
|
|
|
The default value of the select expression is "1".
|
|
|
|
Some examples follow:
|
|
|
|
@example
|
|
# select all frames in input
|
|
select
|
|
|
|
# the above is the same as:
|
|
select=1
|
|
|
|
# skip all frames:
|
|
select=0
|
|
|
|
# select only I-frames
|
|
select='eq(pict_type\,I)'
|
|
|
|
# select one frame every 100
|
|
select='not(mod(n\,100))'
|
|
|
|
# select only frames contained in the 10-20 time interval
|
|
select='gte(t\,10)*lte(t\,20)'
|
|
|
|
# select only I frames contained in the 10-20 time interval
|
|
select='gte(t\,10)*lte(t\,20)*eq(pict_type\,I)'
|
|
|
|
# select frames with a minimum distance of 10 seconds
|
|
select='isnan(prev_selected_t)+gte(t-prev_selected_t\,10)'
|
|
@end example
|
|
|
|
@anchor{setdar}
|
|
@section setdar
|
|
|
|
Set the Display Aspect Ratio for the filter output video.
|
|
|
|
This is done by changing the specified Sample (aka Pixel) Aspect
|
|
Ratio, according to the following equation:
|
|
@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
|
|
|
|
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.
|
|
|
|
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".
|
|
|
|
For example to change the display aspect ratio to 16:9, specify:
|
|
@example
|
|
setdar=16:9
|
|
# the above is equivalent to
|
|
setdar=1.77777
|
|
@end example
|
|
|
|
See also the @ref{setsar} filter documentation.
|
|
|
|
@section setpts
|
|
|
|
Change the PTS (presentation timestamp) of the input video frames.
|
|
|
|
Accept in input an expression evaluated through the eval API, which
|
|
can contain the following constants:
|
|
|
|
@table @option
|
|
@item PTS
|
|
the presentation timestamp in input
|
|
|
|
@item PI
|
|
Greek PI
|
|
|
|
@item PHI
|
|
golden ratio
|
|
|
|
@item E
|
|
Euler number
|
|
|
|
@item N
|
|
the count of the input frame, starting from 0.
|
|
|
|
@item STARTPTS
|
|
the PTS of the first video frame
|
|
|
|
@item INTERLACED
|
|
tell if the current frame is interlaced
|
|
|
|
@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_OUTPTS
|
|
previous output PTS
|
|
|
|
@end table
|
|
|
|
Some examples follow:
|
|
|
|
@example
|
|
# start counting PTS from zero
|
|
setpts=PTS-STARTPTS
|
|
|
|
# fast motion
|
|
setpts=0.5*PTS
|
|
|
|
# slow motion
|
|
setpts=2.0*PTS
|
|
|
|
# fixed rate 25 fps
|
|
setpts=N/(25*TB)
|
|
|
|
# fixed rate 25 fps with some jitter
|
|
setpts='1/(25*TB) * (N + 0.05 * sin(N*2*PI/25))'
|
|
@end example
|
|
|
|
@anchor{setsar}
|
|
@section setsar
|
|
|
|
Set the Sample (aka Pixel) Aspect Ratio for the filter output video.
|
|
|
|
Note that as a consequence of the application of this filter, the
|
|
output display aspect ratio will change according to the following
|
|
equation:
|
|
@math{DAR = HORIZONTAL_RESOLUTION / VERTICAL_RESOLUTION * SAR}
|
|
|
|
Keep in mind that the sample aspect ratio set by this filter may be
|
|
changed by later filters in the filterchain, e.g. if another "setsar"
|
|
or a "setdar" filter is applied.
|
|
|
|
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 fmt
|
|
pixel format name
|
|
|
|
@item sar
|
|
sample aspect ratio of the input frame, expressed in the form
|
|
@var{num}/@var{den}
|
|
|
|
@item s
|
|
size of the input frame, expressed in the form
|
|
@var{width}x@var{height}
|
|
|
|
@item i
|
|
interlaced mode ("P" for "progressive", "T" for top field first, "B"
|
|
for bottom field first)
|
|
|
|
@item iskey
|
|
1 if the frame is a key frame, 0 otherwise
|
|
|
|
@item type
|
|
picture type of the input frame ("I" for an I-frame, "P" for a
|
|
P-frame, "B" for a B-frame, "?" for unknown type).
|
|
Check also the documentation of the @code{AVPictureType} enum and of
|
|
the @code{av_get_picture_type_char} function defined in
|
|
@file{libavutil/avutil.h}.
|
|
|
|
@item checksum
|
|
Adler-32 checksum 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}]"
|
|
@end table
|
|
|
|
@section slicify
|
|
|
|
Pass the images of input video on to next video filter as multiple
|
|
slices.
|
|
|
|
@example
|
|
./avconv -i in.avi -vf "slicify=32" out.avi
|
|
@end example
|
|
|
|
The filter accepts the slice height as parameter. If the parameter is
|
|
not specified it will use the default value of 16.
|
|
|
|
Adding this in the beginning of filter chains should make filtering
|
|
faster due to better use of the memory cache.
|
|
|
|
@section split
|
|
|
|
Split input video into several identical outputs.
|
|
|
|
The filter accepts a single parameter which specifies the number of outputs. If
|
|
unspecified, it defaults to 2.
|
|
|
|
For example
|
|
@example
|
|
avconv -i INPUT -filter_complex split=5 OUTPUT
|
|
@end example
|
|
will create 5 copies of the input video.
|
|
|
|
@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:
|
|
|
|
@table @samp
|
|
@item 0
|
|
Rotate by 90 degrees counterclockwise and vertically flip (default), that is:
|
|
@example
|
|
L.R L.l
|
|
. . -> . .
|
|
l.r R.r
|
|
@end example
|
|
|
|
@item 1
|
|
Rotate by 90 degrees clockwise, that is:
|
|
@example
|
|
L.R l.L
|
|
. . -> . .
|
|
l.r r.R
|
|
@end example
|
|
|
|
@item 2
|
|
Rotate by 90 degrees counterclockwise, that is:
|
|
@example
|
|
L.R R.r
|
|
. . -> . .
|
|
l.r L.l
|
|
@end example
|
|
|
|
@item 3
|
|
Rotate by 90 degrees clockwise and vertically flip, that is:
|
|
@example
|
|
L.R r.R
|
|
. . -> . .
|
|
l.r l.L
|
|
@end example
|
|
@end table
|
|
|
|
@section unsharp
|
|
|
|
Sharpen or blur the input video.
|
|
|
|
It accepts the following parameters:
|
|
@var{luma_msize_x}:@var{luma_msize_y}:@var{luma_amount}:@var{chroma_msize_x}:@var{chroma_msize_y}:@var{chroma_amount}
|
|
|
|
Negative values for the amount will blur the input video, while positive
|
|
values will sharpen. All parameters are optional and default to the
|
|
equivalent of the string '5:5:1.0:5:5:0.0'.
|
|
|
|
@table @option
|
|
|
|
@item luma_msize_x
|
|
Set the luma matrix horizontal size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@item luma_msize_y
|
|
Set the luma matrix vertical size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@item luma_amount
|
|
Set the luma effect strength. It can be a float number between -2.0
|
|
and 5.0, default value is 1.0.
|
|
|
|
@item chroma_msize_x
|
|
Set the chroma matrix horizontal size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@item chroma_msize_y
|
|
Set the chroma matrix vertical size. It can be an integer between 3
|
|
and 13, default value is 5.
|
|
|
|
@item luma_amount
|
|
Set the chroma effect strength. It can be a float number between -2.0
|
|
and 5.0, default value is 0.0.
|
|
|
|
@end table
|
|
|
|
@example
|
|
# Strong luma sharpen effect parameters
|
|
unsharp=7:7:2.5
|
|
|
|
# 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
|
|
@end example
|
|
|
|
@section vflip
|
|
|
|
Flip the input video vertically.
|
|
|
|
@example
|
|
./avconv -i in.avi -vf "vflip" out.avi
|
|
@end example
|
|
|
|
@section yadif
|
|
|
|
Deinterlace the input video ("yadif" means "yet another deinterlacing
|
|
filter").
|
|
|
|
It accepts the optional parameters: @var{mode}:@var{parity}:@var{auto}.
|
|
|
|
@var{mode} specifies the interlacing mode to adopt, accepts one of the
|
|
following values:
|
|
|
|
@table @option
|
|
@item 0
|
|
output 1 frame for each frame
|
|
@item 1
|
|
output 1 frame for each field
|
|
@item 2
|
|
like 0 but skips spatial interlacing check
|
|
@item 3
|
|
like 1 but skips spatial interlacing check
|
|
@end table
|
|
|
|
Default value is 0.
|
|
|
|
@var{parity} specifies the picture field parity assumed for the input
|
|
interlaced video, accepts one of the following values:
|
|
|
|
@table @option
|
|
@item 0
|
|
assume top field first
|
|
@item 1
|
|
assume bottom field first
|
|
@item -1
|
|
enable automatic detection
|
|
@end table
|
|
|
|
Default value is -1.
|
|
If interlacing is unknown or decoder does not export this information,
|
|
top field first will be assumed.
|
|
|
|
@var{auto} specifies if deinterlacer should trust the interlaced flag
|
|
and only deinterlace frames marked as interlaced
|
|
|
|
@table @option
|
|
@item 0
|
|
deinterlace all frames
|
|
@item 1
|
|
only deinterlace frames marked as interlaced
|
|
@end table
|
|
|
|
Default value is 0.
|
|
|
|
@c man end VIDEO FILTERS
|
|
|
|
@chapter Video Sources
|
|
@c man begin VIDEO SOURCES
|
|
|
|
Below is a description of the currently available video sources.
|
|
|
|
@section buffer
|
|
|
|
Buffer video frames, and make them available to the filter chain.
|
|
|
|
This source is mainly intended for a programmatic use, in particular
|
|
through the interface defined in @file{libavfilter/vsrc_buffer.h}.
|
|
|
|
It accepts 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.
|
|
|
|
@table @option
|
|
|
|
@item width, height
|
|
Specify the width and height of the buffered video frames.
|
|
|
|
@item pix_fmt_string
|
|
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 sample_aspect_ratio.num, sample_aspect_ratio.den
|
|
Specify numerator and denominator of the sample aspect ratio assumed
|
|
by the video frames.
|
|
@end table
|
|
|
|
For example:
|
|
@example
|
|
buffer=320:240:yuv410p:1:24:1:1
|
|
@end example
|
|
|
|
will instruct the source to accept video frames with size 320x240 and
|
|
with format "yuv410p", assuming 1/24 as the timestamps timebase and
|
|
square pixels (1:1 sample aspect ratio).
|
|
Since the pixel format with name "yuv410p" corresponds to the number 6
|
|
(check the enum AVPixelFormat definition in @file{libavutil/pixfmt.h}),
|
|
this example corresponds to:
|
|
@example
|
|
buffer=320:240:6:1:24
|
|
@end example
|
|
|
|
@section color
|
|
|
|
Provide an uniformly colored input.
|
|
|
|
It accepts the following parameters:
|
|
@var{color}:@var{frame_size}:@var{frame_rate}
|
|
|
|
Follows the description of the accepted parameters.
|
|
|
|
@table @option
|
|
|
|
@item color
|
|
Specify the color of the source. It can be the name of a color (case
|
|
insensitive match) or a 0xRRGGBB[AA] sequence, possibly followed by an
|
|
alpha specifier. The default value is "black".
|
|
|
|
@item 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".
|
|
|
|
@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".
|
|
|
|
@end table
|
|
|
|
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".
|
|
|
|
@example
|
|
"color=red@@0.2:qcif:10 [color]; [in][color] overlay [out]"
|
|
@end example
|
|
|
|
@section movie
|
|
|
|
Read a video stream from a movie container.
|
|
|
|
Note that this source is a hack that bypasses the standard input path. It can be
|
|
useful in applications that do not support arbitrary filter graphs, but its use
|
|
is discouraged in those that do. Specifically in @command{avconv} this filter
|
|
should never be used, the @option{-filter_complex} option fully replaces it.
|
|
|
|
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 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".
|
|
|
|
@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:
|
|
@example
|
|
# skip 3.2 seconds from the start of the avi file in.avi, and overlay it
|
|
# on top of the input labelled as "in".
|
|
movie=in.avi:seek_point=3.2, scale=180:-1, setpts=PTS-STARTPTS [movie];
|
|
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
|
|
|
|
# read from a video4linux2 device, and overlay it on top of the input
|
|
# labelled as "in"
|
|
movie=/dev/video0:f=video4linux2, scale=180:-1, setpts=PTS-STARTPTS [movie];
|
|
[in] setpts=PTS-STARTPTS, [movie] overlay=16:16 [out]
|
|
|
|
@end example
|
|
|
|
@section nullsrc
|
|
|
|
Null video source, never return images. It is mainly useful as a
|
|
template and to be employed in analysis / debugging tools.
|
|
|
|
It accepts as optional parameter a string of the form
|
|
@var{width}:@var{height}:@var{timebase}.
|
|
|
|
@var{width} and @var{height} specify the size of the configured
|
|
source. The default values of @var{width} and @var{height} are
|
|
respectively 352 and 288 (corresponding to the CIF size format).
|
|
|
|
@var{timebase} specifies an arithmetic expression representing a
|
|
timebase. The expression can contain the constants "PI", "E", "PHI",
|
|
"AVTB" (the default timebase), and defaults to the value "AVTB".
|
|
|
|
@section frei0r_src
|
|
|
|
Provide a frei0r source.
|
|
|
|
To enable compilation of this filter you need to install the frei0r
|
|
header and configure Libav with --enable-frei0r.
|
|
|
|
The source supports the syntax:
|
|
@example
|
|
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
|
|
@end example
|
|
|
|
@var{size} is the size of the video to generate, may be a string of the
|
|
form @var{width}x@var{height} or a frame size abbreviation.
|
|
@var{rate} is the rate of the video to generate, may be a string of
|
|
the form @var{num}/@var{den} or a frame rate abbreviation.
|
|
@var{src_name} is the name to the frei0r source to load. For more
|
|
information regarding frei0r and how to set the parameters read the
|
|
section @ref{frei0r} in the description of the video filters.
|
|
|
|
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
|
|
|
|
@section rgbtestsrc, testsrc
|
|
|
|
The @code{rgbtestsrc} source generates an RGB test pattern useful for
|
|
detecting RGB vs BGR issues. You should see a red, green and blue
|
|
stripe from top to bottom.
|
|
|
|
The @code{testsrc} source generates a test video pattern, showing a
|
|
color pattern, a scrolling gradient and a timestamp. This is mainly
|
|
intended for testing purposes.
|
|
|
|
Both sources accept an optional sequence of @var{key}=@var{value} pairs,
|
|
separated by ":". The description of the accepted options follows.
|
|
|
|
@table @option
|
|
|
|
@item size, s
|
|
Specify the size of the sourced video, it may be a string of the form
|
|
@var{width}x@var{height}, or the name of a size abbreviation. The
|
|
default value is "320x240".
|
|
|
|
@item rate, r
|
|
Specify the frame rate of the sourced video, as the number of frames
|
|
generated per second. It has to be a string in the format
|
|
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
|
|
number or a valid video frame rate abbreviation. The default value is
|
|
"25".
|
|
|
|
@item sar
|
|
Set the sample aspect ratio of the sourced video.
|
|
|
|
@item duration
|
|
Set the video duration of the sourced video. The accepted syntax is:
|
|
@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.
|
|
@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 framerate of 10 frames per second.
|
|
|
|
@c man end VIDEO SOURCES
|
|
|
|
@chapter Video Sinks
|
|
@c man begin VIDEO SINKS
|
|
|
|
Below is a description of the currently available video sinks.
|
|
|
|
@section buffersink
|
|
|
|
Buffer video frames, and make them available to the end of the filter
|
|
graph.
|
|
|
|
This sink is intended for a programmatic use through the interface defined in
|
|
@file{libavfilter/buffersink.h}.
|
|
|
|
@section nullsink
|
|
|
|
Null video sink, do absolutely nothing with the input video. It is
|
|
mainly useful as a template and to be employed in analysis / debugging
|
|
tools.
|
|
|
|
@c man end VIDEO SINKS
|