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This allows for padding/trimming at the start of stream. By default, no assumption is made about the first frame's expected pts, so no padding or trimming is done.
2347 lines
66 KiB
Plaintext
2347 lines
66 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 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.
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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.
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@item max_comp
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Maximum compensation in samples per second.
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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{libavcodec/audioconvert.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
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@example
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boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
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@end example
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@end itemize
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@section copy
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Copy the input source unchanged to the output. Mainly useful for
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testing purposes.
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@section crop
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Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}.
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The parameters are expressions containing the following constants:
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@table @option
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@item E, PI, PHI
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the corresponding mathematical approximated values for e
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(euler number), pi (greek PI), PHI (golden ratio)
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@item x, y
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the computed values for @var{x} and @var{y}. They are evaluated for
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each new frame.
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@item in_w, in_h
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the input width and height
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@item iw, ih
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same as @var{in_w} and @var{in_h}
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@item out_w, out_h
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the output (cropped) width and height
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@item ow, oh
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same as @var{out_w} and @var{out_h}
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|
|
@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
|
|
@var{c0} (first pixel component)
|
|
@var{c1} (second pixel component)
|
|
@var{c2} (third pixel component)
|
|
@var{c3} (fourth pixel component, corresponds to the alpha component)
|
|
@end table
|
|
|
|
The exact component associated to each option depends on the format in
|
|
input.
|
|
|
|
The @var{lutrgb} filter requires RGB pixel formats in input, and
|
|
accepts the options:
|
|
@table @option
|
|
@var{r} (red component)
|
|
@var{g} (green component)
|
|
@var{b} (blue component)
|
|
@var{a} (alpha component)
|
|
@end table
|
|
|
|
The @var{lutyuv} filter requires YUV pixel formats in input, and
|
|
accepts the options:
|
|
@table @option
|
|
@var{y} (Y/luminance component)
|
|
@var{u} (U/Cb component)
|
|
@var{v} (V/Cr component)
|
|
@var{a} (alpha component)
|
|
@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 PixelFormat 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.
|
|
|
|
It accepts the syntax: @var{movie_name}[:@var{options}] where
|
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@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
|