3473 lines
96 KiB
Plaintext
3473 lines
96 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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@section Filtergraph syntax
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A filtergraph can be represented using a textual representation, which
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is recognized by the @code{-vf} option of the ff*
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tools, and by the @code{avfilter_graph_parse()} 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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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} ::= @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 FFmpeg build, you can disable any of the
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existing filters using @code{--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 aconvert
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Convert the input audio format to the specified formats.
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The filter accepts a string of the form:
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"@var{sample_format}:@var{channel_layout}".
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@var{sample_format} specifies the sample format, and can be a string or the
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corresponding numeric value defined in @file{libavutil/samplefmt.h}. Use 'p'
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suffix for a planar sample format.
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@var{channel_layout} specifies the channel layout, and can be a string
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or the corresponding number value defined in @file{libavutil/audioconvert.h}.
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The special parameter "auto", signifies that the filter will
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automatically select the output format depending on the output filter.
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Some examples follow.
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@itemize
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@item
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Convert input to float, planar, stereo:
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@example
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aconvert=fltp:stereo
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@end example
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@item
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Convert input to unsigned 8-bit, automatically select out channel layout:
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@example
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aconvert=u8:auto
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@end example
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@end itemize
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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 three lists of formats, separated by ":", in the form:
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"@var{sample_formats}:@var{channel_layouts}:@var{packing_formats}".
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Elements in each list are separated by "," which has to be escaped in the
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filtergraph specification.
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The special parameter "all", in place of a list of elements, signifies all
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supported formats.
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Some examples follow:
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@example
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aformat=u8\\,s16:mono:packed
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aformat=s16:mono\\,stereo:all
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@end example
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@section amerge
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Merge two audio streams into a single multi-channel stream.
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This filter does not need any argument.
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If the channel layouts of the inputs are disjoint, and therefore compatible,
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the channel layout of the output will be set accordingly and the channels
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will be reordered as necessary. If the channel layouts of the inputs are not
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disjoint, the output will have all the channels of the first input then all
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the channels of the second input, in that order, and the channel layout of
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the output will be the default value corresponding to the total number of
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channels.
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For example, if the first input is in 2.1 (FL+FR+LF) and the second input
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is FC+BL+BR, then the output will be in 5.1, with the channels in the
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following order: a1, a2, b1, a3, b2, b3 (a1 is the first channel of the
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first input, b1 is the first channel of the second input).
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On the other hand, if both input are in stereo, the output channels will be
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in the default order: a1, a2, b1, b2, and the channel layout will be
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arbitrarily set to 4.0, which may or may not be the expected value.
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Both inputs must have the same sample rate, format and packing.
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If inputs do not have the same duration, the output will stop with the
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shortest.
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Example: merge two mono files into a stereo stream:
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@example
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amovie=left.wav [l] ; amovie=right.mp3 [r] ; [l] [r] amerge
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@end example
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If you need to do multiple merges (for instance multiple mono audio streams in
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a single video media), you can do:
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@example
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ffmpeg -f lavfi -i "
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amovie=input.mkv:si=0 [a0];
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amovie=input.mkv:si=1 [a1];
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amovie=input.mkv:si=2 [a2];
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amovie=input.mkv:si=3 [a3];
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amovie=input.mkv:si=4 [a4];
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amovie=input.mkv:si=5 [a5];
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[a0][a1] amerge [x0];
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[x0][a2] amerge [x1];
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[x1][a3] amerge [x2];
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[x2][a4] amerge [x3];
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[x3][a5] amerge" -c:a pcm_s16le output.mkv
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@end example
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@section anull
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Pass the audio source unchanged to the output.
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@section aresample
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Resample the input audio to the specified sample rate.
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The filter accepts exactly one parameter, the output sample rate. If not
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specified then the filter will automatically convert between its input
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and output sample rates.
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For example, to resample the input audio to 44100Hz:
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@example
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aresample=44100
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@end example
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@section ashowinfo
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Show a line containing various information for each input audio frame.
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The input audio is not modified.
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The shown line contains a sequence of key/value pairs of the form
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@var{key}:@var{value}.
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A description of each shown parameter follows:
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@table @option
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@item n
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sequential number of the input frame, starting from 0
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@item pts
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presentation TimeStamp of the input frame, expressed as a number of
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time base units. The time base unit depends on the filter input pad, and
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is usually 1/@var{sample_rate}.
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@item pts_time
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presentation TimeStamp of the input frame, expressed as a number of
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seconds
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@item pos
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position of the frame in the input stream, -1 if this information in
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unavailable and/or meaningless (for example in case of synthetic audio)
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@item fmt
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sample format name
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@item chlayout
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channel layout description
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@item nb_samples
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number of samples (per each channel) contained in the filtered frame
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@item rate
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sample rate for the audio frame
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@item planar
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if the packing format is planar, 0 if packed
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@item checksum
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Adler-32 checksum (printed in hexadecimal) of all the planes of the input frame
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@item plane_checksum
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Adler-32 checksum (printed in hexadecimal) for each input frame plane,
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expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3} @var{c4} @var{c5}
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@var{c6} @var{c7}]"
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@end table
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@section asplit
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Pass on the input audio to two outputs. Both outputs are identical to
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the input audio.
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For example:
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@example
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[in] asplit[out0], showaudio[out1]
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@end example
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will create two separate outputs from the same input, one cropped and
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one padded.
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@section astreamsync
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Forward two audio streams and control the order the buffers are forwarded.
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The argument to the filter is an expression deciding which stream should be
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forwarded next: if the result is negative, the first stream is forwarded; if
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the result is positive or zero, the second stream is forwarded. It can use
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the following variables:
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@table @var
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@item b1 b2
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number of buffers forwarded so far on each stream
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@item s1 s2
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number of samples forwarded so far on each stream
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@item t1 t2
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current timestamp of each stream
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@end table
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The default value is @code{t1-t2}, which means to always forward the stream
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that has a smaller timestamp.
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Example: stress-test @code{amerge} by randomly sending buffers on the wrong
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input, while avoiding too much of a desynchronization:
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@example
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amovie=file.ogg [a] ; amovie=file.mp3 [b] ;
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[a] [b] astreamsync=(2*random(1))-1+tanh(5*(t1-t2)) [a2] [b2] ;
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[a2] [b2] amerge
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@end example
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@section earwax
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Make audio easier to listen to on headphones.
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This filter adds `cues' to 44.1kHz stereo (i.e. audio CD format) audio
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so that when listened to on headphones the stereo image is moved from
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inside your head (standard for headphones) to outside and in front of
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the listener (standard for speakers).
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Ported from SoX.
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@section pan
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Mix channels with specific gain levels. The filter accepts the output
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channel layout followed by a set of channels definitions.
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This filter is also designed to remap efficiently the channels of an audio
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stream.
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The filter accepts parameters of the form:
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"@var{l}:@var{outdef}:@var{outdef}:..."
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@table @option
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@item l
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output channel layout or number of channels
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@item outdef
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output channel specification, of the form:
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"@var{out_name}=[@var{gain}*]@var{in_name}[+[@var{gain}*]@var{in_name}...]"
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@item out_name
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output channel to define, either a channel name (FL, FR, etc.) or a channel
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number (c0, c1, etc.)
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@item gain
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multiplicative coefficient for the channel, 1 leaving the volume unchanged
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@item in_name
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input channel to use, see out_name for details; it is not possible to mix
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named and numbered input channels
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@end table
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If the `=' in a channel specification is replaced by `<', then the gains for
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that specification will be renormalized so that the total is 1, thus
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avoiding clipping noise.
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@subsection Mixing examples
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For example, if you want to down-mix from stereo to mono, but with a bigger
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factor for the left channel:
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@example
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pan=1:c0=0.9*c0+0.1*c1
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@end example
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A customized down-mix to stereo that works automatically for 3-, 4-, 5- and
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7-channels surround:
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@example
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pan=stereo: FL < FL + 0.5*FC + 0.6*BL + 0.6*SL : FR < FR + 0.5*FC + 0.6*BR + 0.6*SR
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@end example
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Note that @command{ffmpeg} integrates a default down-mix (and up-mix) system
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that should be preferred (see "-ac" option) unless you have very specific
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needs.
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@subsection Remapping examples
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The channel remapping will be effective if, and only if:
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@itemize
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@item gain coefficients are zeroes or ones,
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@item only one input per channel output,
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@end itemize
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If all these conditions are satisfied, the filter will notify the user ("Pure
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channel mapping detected"), and use an optimized and lossless method to do the
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remapping.
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For example, if you have a 5.1 source and want a stereo audio stream by
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dropping the extra channels:
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@example
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pan="stereo: c0=FL : c1=FR"
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@end example
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Given the same source, you can also switch front left and front right channels
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and keep the input channel layout:
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@example
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pan="5.1: c0=c1 : c1=c0 : c2=c2 : c3=c3 : c4=c4 : c5=c5"
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@end example
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If the input is a stereo audio stream, you can mute the front left channel (and
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still keep the stereo channel layout) with:
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@example
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pan="stereo:c1=c1"
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@end example
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Still with a stereo audio stream input, you can copy the right channel in both
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front left and right:
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@example
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pan="stereo: c0=FR : c1=FR"
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@end example
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@section silencedetect
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Detect silence in an audio stream.
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This filter logs a message when it detects that the input audio volume is less
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or equal to a noise tolerance value for a duration greater or equal to the
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minimum detected noise duration.
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The printed times and duration are expressed in seconds.
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@table @option
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@item duration, d
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Set silence duration until notification (default is 2 seconds).
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@item noise, n
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Set noise tolerance. Can be specified in dB (in case "dB" is appended to the
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specified value) or amplitude ratio. Default is -60dB, or 0.001.
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@end table
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Detect 5 seconds of silence with -50dB noise tolerance:
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@example
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silencedetect=n=-50dB:d=5
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@end example
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Complete example with @command{ffmpeg} to detect silence with 0.0001 noise
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tolerance in @file{silence.mp3}:
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@example
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ffmpeg -f lavfi -i amovie=silence.mp3,silencedetect=noise=0.0001 -f null -
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@end example
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@section volume
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Adjust the input audio volume.
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The filter accepts exactly one parameter @var{vol}, which expresses
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how the audio volume will be increased or decreased.
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Output values are clipped to the maximum value.
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If @var{vol} is expressed as a decimal number, the output audio
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volume is given by the relation:
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@example
|
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@var{output_volume} = @var{vol} * @var{input_volume}
|
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@end example
|
||
|
||
If @var{vol} is expressed as a decimal number followed by the string
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"dB", the value represents the requested change in decibels of the
|
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input audio power, and the output audio volume is given by the
|
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relation:
|
||
@example
|
||
@var{output_volume} = 10^(@var{vol}/20) * @var{input_volume}
|
||
@end example
|
||
|
||
Otherwise @var{vol} is considered an expression and its evaluated
|
||
value is used for computing the output audio volume according to the
|
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first relation.
|
||
|
||
Default value for @var{vol} is 1.0.
|
||
|
||
@subsection Examples
|
||
|
||
@itemize
|
||
@item
|
||
Half the input audio volume:
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||
@example
|
||
volume=0.5
|
||
@end example
|
||
|
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The above example is equivalent to:
|
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@example
|
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volume=1/2
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@end example
|
||
|
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@item
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Decrease input audio power by 12 decibels:
|
||
@example
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volume=-12dB
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@end example
|
||
@end itemize
|
||
|
||
@c man end AUDIO FILTERS
|
||
|
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@chapter Audio Sources
|
||
@c man begin AUDIO SOURCES
|
||
|
||
Below is a description of the currently available audio sources.
|
||
|
||
@section abuffer
|
||
|
||
Buffer audio frames, and make them available to the filter chain.
|
||
|
||
This source is mainly intended for a programmatic use, in particular
|
||
through the interface defined in @file{libavfilter/asrc_abuffer.h}.
|
||
|
||
It accepts the following mandatory parameters:
|
||
@var{sample_rate}:@var{sample_fmt}:@var{channel_layout}:@var{packing}
|
||
|
||
@table @option
|
||
|
||
@item sample_rate
|
||
The sample rate of the incoming audio buffers.
|
||
|
||
@item sample_fmt
|
||
The sample format of the incoming audio buffers.
|
||
Either a sample format name or its corresponging integer representation from
|
||
the enum AVSampleFormat in @file{libavutil/samplefmt.h}
|
||
|
||
@item channel_layout
|
||
The channel layout of the incoming audio buffers.
|
||
Either a channel layout name from channel_layout_map in
|
||
@file{libavutil/audioconvert.c} or its corresponding integer representation
|
||
from the AV_CH_LAYOUT_* macros in @file{libavutil/audioconvert.h}
|
||
|
||
@item packing
|
||
Either "packed" or "planar", or their integer representation: 0 or 1
|
||
respectively.
|
||
|
||
@end table
|
||
|
||
For example:
|
||
@example
|
||
abuffer=44100:s16:stereo:planar
|
||
@end example
|
||
|
||
will instruct the source to accept planar 16bit signed stereo at 44100Hz.
|
||
Since the sample format with name "s16" corresponds to the number
|
||
1 and the "stereo" channel layout corresponds to the value 0x3, this is
|
||
equivalent to:
|
||
@example
|
||
abuffer=44100:1:0x3:1
|
||
@end example
|
||
|
||
@section aevalsrc
|
||
|
||
Generate an audio signal specified by an expression.
|
||
|
||
This source accepts in input one or more expressions (one for each
|
||
channel), which are evaluated and used to generate a corresponding
|
||
audio signal.
|
||
|
||
It accepts the syntax: @var{exprs}[::@var{options}].
|
||
@var{exprs} is a list of expressions separated by ":", one for each
|
||
separate channel. The output channel layout depends on the number of
|
||
provided expressions, up to 8 channels are supported.
|
||
|
||
@var{options} is an optional sequence of @var{key}=@var{value} pairs,
|
||
separated by ":".
|
||
|
||
The description of the accepted options follows.
|
||
|
||
@table @option
|
||
|
||
@item duration, d
|
||
Set the minimum duration of the sourced audio. See the function
|
||
@code{av_parse_time()} for the accepted format.
|
||
Note that the resulting duration may be greater than the specified
|
||
duration, as the generated audio is always cut at the end of a
|
||
complete frame.
|
||
|
||
If not specified, or the expressed duration is negative, the audio is
|
||
supposed to be generated forever.
|
||
|
||
@item nb_samples, n
|
||
Set the number of samples per channel per each output frame,
|
||
default to 1024.
|
||
|
||
@item sample_rate, s
|
||
Specify the sample rate, default to 44100.
|
||
@end table
|
||
|
||
Each expression in @var{exprs} can contain the following constants:
|
||
|
||
@table @option
|
||
@item n
|
||
number of the evaluated sample, starting from 0
|
||
|
||
@item t
|
||
time of the evaluated sample expressed in seconds, starting from 0
|
||
|
||
@item s
|
||
sample rate
|
||
|
||
@end table
|
||
|
||
@subsection Examples
|
||
|
||
@itemize
|
||
|
||
@item
|
||
Generate silence:
|
||
@example
|
||
aevalsrc=0
|
||
@end example
|
||
|
||
@item
|
||
|
||
Generate a sin signal with frequency of 440 Hz, set sample rate to
|
||
8000 Hz:
|
||
@example
|
||
aevalsrc="sin(440*2*PI*t)::s=8000"
|
||
@end example
|
||
|
||
@item
|
||
Generate white noise:
|
||
@example
|
||
aevalsrc="-2+random(0)"
|
||
@end example
|
||
|
||
@item
|
||
Generate an amplitude modulated signal:
|
||
@example
|
||
aevalsrc="sin(10*2*PI*t)*sin(880*2*PI*t)"
|
||
@end example
|
||
|
||
@item
|
||
Generate 2.5 Hz binaural beats on a 360 Hz carrier:
|
||
@example
|
||
aevalsrc="0.1*sin(2*PI*(360-2.5/2)*t) : 0.1*sin(2*PI*(360+2.5/2)*t)"
|
||
@end example
|
||
|
||
@end itemize
|
||
|
||
@section amovie
|
||
|
||
Read an audio stream from a movie container.
|
||
|
||
It accepts the syntax: @var{movie_name}[:@var{options}] where
|
||
@var{movie_name} is the name of the resource to read (not necessarily
|
||
a file but also a device or a stream accessed through some protocol),
|
||
and @var{options} is an optional sequence of @var{key}=@var{value}
|
||
pairs, separated by ":".
|
||
|
||
The description of the accepted options follows.
|
||
|
||
@table @option
|
||
|
||
@item format_name, f
|
||
Specify 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
|
||
Specify 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
|
||
Specify the index of the audio stream to read. If the value is -1,
|
||
the best suited audio stream will be automatically selected. Default
|
||
value is "-1".
|
||
|
||
@end table
|
||
|
||
@section anullsrc
|
||
|
||
Null audio source, return unprocessed audio frames. It is mainly useful
|
||
as a template and to be employed in analysis / debugging tools, or as
|
||
the source for filters which ignore the input data (for example the sox
|
||
synth filter).
|
||
|
||
It accepts an optional sequence of @var{key}=@var{value} pairs,
|
||
separated by ":".
|
||
|
||
The description of the accepted options follows.
|
||
|
||
@table @option
|
||
|
||
@item sample_rate, s
|
||
Specify the sample rate, and defaults to 44100.
|
||
|
||
@item channel_layout, cl
|
||
|
||
Specify the channel layout, and can be either an integer or a string
|
||
representing a channel layout. The default value of @var{channel_layout}
|
||
is "stereo".
|
||
|
||
Check the channel_layout_map definition in
|
||
@file{libavcodec/audioconvert.c} for the mapping between strings and
|
||
channel layout values.
|
||
|
||
@item nb_samples, n
|
||
Set the number of samples per requested frames.
|
||
|
||
@end table
|
||
|
||
Follow some examples:
|
||
@example
|
||
# set the sample rate to 48000 Hz and the channel layout to AV_CH_LAYOUT_MONO.
|
||
anullsrc=r=48000:cl=4
|
||
|
||
# same as
|
||
anullsrc=r=48000:cl=mono
|
||
@end example
|
||
|
||
@c man end AUDIO SOURCES
|
||
|
||
@chapter Audio Sinks
|
||
@c man begin AUDIO SINKS
|
||
|
||
Below is a description of the currently available audio sinks.
|
||
|
||
@section abuffersink
|
||
|
||
Buffer audio frames, and make them available to the end of filter chain.
|
||
|
||
This sink is mainly intended for programmatic use, in particular
|
||
through the interface defined in @file{libavfilter/buffersink.h}.
|
||
|
||
It requires a pointer to an AVABufferSinkContext structure, which
|
||
defines the incoming buffers' formats, to be passed as the opaque
|
||
parameter to @code{avfilter_init_filter} for initialization.
|
||
|
||
@section anullsink
|
||
|
||
Null audio sink, do absolutely nothing with the input audio. It is
|
||
mainly useful as a template and to be employed in analysis / debugging
|
||
tools.
|
||
|
||
@c man end AUDIO SINKS
|
||
|
||
@chapter Video Filters
|
||
@c man begin VIDEO FILTERS
|
||
|
||
When you configure your FFmpeg build, you can disable any of the
|
||
existing filters using @code{--disable-filters}.
|
||
The configure output will show the video filters included in your
|
||
build.
|
||
|
||
Below is a description of the currently available video filters.
|
||
|
||
@section ass
|
||
|
||
Draw ASS (Advanced Substation Alpha) subtitles on top of input video
|
||
using the libass library.
|
||
|
||
To enable compilation of this filter you need to configure FFmpeg with
|
||
@code{--enable-libass}.
|
||
|
||
This filter accepts the syntax: @var{ass_filename}[:@var{options}],
|
||
where @var{ass_filename} is the filename of the ASS file to read, and
|
||
@var{options} is an optional sequence of @var{key}=@var{value} pairs,
|
||
separated by ":".
|
||
|
||
A description of the accepted options follows.
|
||
|
||
@table @option
|
||
@item dar
|
||
Specifies the display aspect ratio adopted for rendering the
|
||
subtitles. Default value is "1.0".
|
||
@end table
|
||
|
||
For example, to render the file @file{sub.ass} on top of the input
|
||
video, use the command:
|
||
@example
|
||
ass=sub.ass
|
||
@end example
|
||
|
||
@section bbox
|
||
|
||
Compute the bounding box for the non-black pixels in the input frame
|
||
luminance plane.
|
||
|
||
This filter computes the bounding box containing all the pixels with a
|
||
luminance value greater than the minimum allowed value.
|
||
The parameters describing the bounding box are printed on the filter
|
||
log.
|
||
|
||
@section blackdetect
|
||
|
||
Detect video intervals that are (almost) completely black. Can be
|
||
useful to detect chapter transitions, commercials, or invalid
|
||
recordings. Output lines contains the time for the start, end and
|
||
duration of the detected black interval expressed in seconds.
|
||
|
||
In order to display the output lines, you need to set the loglevel at
|
||
least to the AV_LOG_INFO value.
|
||
|
||
This filter accepts a list of options in the form of
|
||
@var{key}=@var{value} pairs separated by ":". A description of the
|
||
accepted options follows.
|
||
|
||
@table @option
|
||
@item black_min_duration, d
|
||
Set the minimum detected black duration expressed in seconds. It must
|
||
be a non-negative floating point number.
|
||
|
||
Default value is 2.0.
|
||
|
||
@item picture_black_ratio_th, pic_th
|
||
Set the threshold for considering a picture "black".
|
||
Express the minimum value for the ratio:
|
||
@example
|
||
@var{nb_black_pixels} / @var{nb_pixels}
|
||
@end example
|
||
|
||
for which a picture is considered black.
|
||
Default value is 0.98.
|
||
|
||
@item pixel_black_th, pix_th
|
||
Set the threshold for considering a pixel "black".
|
||
|
||
The threshold expresses the maximum pixel luminance value for which a
|
||
pixel is considered "black". The provided value is scaled according to
|
||
the following equation:
|
||
@example
|
||
@var{absolute_threshold} = @var{luminance_minimum_value} + @var{pixel_black_th} * @var{luminance_range_size}
|
||
@end example
|
||
|
||
@var{luminance_range_size} and @var{luminance_minimum_value} depend on
|
||
the input video format, the range is [0-255] for YUV full-range
|
||
formats and [16-235] for YUV non full-range formats.
|
||
|
||
Default value is 0.10.
|
||
@end table
|
||
|
||
The following example sets the maximum pixel threshold to the minimum
|
||
value, and detects only black intervals of 2 or more seconds:
|
||
@example
|
||
blackdetect=d=2:pix_th=0.00
|
||
@end example
|
||
|
||
@section blackframe
|
||
|
||
Detect frames that are (almost) completely black. Can be useful to
|
||
detect chapter transitions or commercials. Output lines consist of
|
||
the frame number of the detected frame, the percentage of blackness,
|
||
the position in the file if known or -1 and the timestamp in seconds.
|
||
|
||
In order to display the output lines, you need to set the loglevel at
|
||
least to the AV_LOG_INFO value.
|
||
|
||
The filter accepts the syntax:
|
||
@example
|
||
blackframe[=@var{amount}:[@var{threshold}]]
|
||
@end example
|
||
|
||
@var{amount} is the percentage of the pixels that have to be below the
|
||
threshold, and defaults to 98.
|
||
|
||
@var{threshold} is the threshold below which a pixel value is
|
||
considered black, and defaults to 32.
|
||
|
||
@section boxblur
|
||
|
||
Apply boxblur algorithm to the input video.
|
||
|
||
This filter accepts the parameters:
|
||
@var{luma_radius}:@var{luma_power}:@var{chroma_radius}:@var{chroma_power}:@var{alpha_radius}:@var{alpha_power}
|
||
|
||
Chroma and alpha parameters are optional, if not specified they default
|
||
to the corresponding values set for @var{luma_radius} and
|
||
@var{luma_power}.
|
||
|
||
@var{luma_radius}, @var{chroma_radius}, and @var{alpha_radius} represent
|
||
the radius in pixels of the box used for blurring the corresponding
|
||
input plane. They are expressions, and can contain the following
|
||
constants:
|
||
@table @option
|
||
@item w, h
|
||
the input width and height in pixels
|
||
|
||
@item cw, ch
|
||
the input chroma image width and height in pixels
|
||
|
||
@item hsub, vsub
|
||
horizontal and vertical chroma subsample values. For example for the
|
||
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
||
@end table
|
||
|
||
The radius must be a non-negative number, and must not be greater than
|
||
the value of the expression @code{min(w,h)/2} for the luma and alpha planes,
|
||
and of @code{min(cw,ch)/2} for the chroma planes.
|
||
|
||
@var{luma_power}, @var{chroma_power}, and @var{alpha_power} represent
|
||
how many times the boxblur filter is applied to the corresponding
|
||
plane.
|
||
|
||
Some examples follow:
|
||
|
||
@itemize
|
||
|
||
@item
|
||
Apply a boxblur filter with luma, chroma, and alpha radius
|
||
set to 2:
|
||
@example
|
||
boxblur=2:1
|
||
@end example
|
||
|
||
@item
|
||
Set luma radius to 2, alpha and chroma radius to 0
|
||
@example
|
||
boxblur=2:1:0:0:0:0
|
||
@end example
|
||
|
||
@item
|
||
Set luma and chroma radius to a fraction of the video dimension
|
||
@example
|
||
boxblur=min(h\,w)/10:1:min(cw\,ch)/10:1
|
||
@end example
|
||
|
||
@end itemize
|
||
|
||
@section copy
|
||
|
||
Copy the input source unchanged to the output. Mainly useful for
|
||
testing purposes.
|
||
|
||
@section crop
|
||
|
||
Crop the input video to @var{out_w}:@var{out_h}:@var{x}:@var{y}:@var{keep_aspect}
|
||
|
||
The @var{keep_aspect} parameter is optional, if specified and set to a
|
||
non-zero value will force the output display aspect ratio to be the
|
||
same of the input, by changing the output sample aspect ratio.
|
||
|
||
The @var{out_w}, @var{out_h}, @var{x}, @var{y} parameters are
|
||
expressions containing the following constants:
|
||
|
||
@table @option
|
||
@item x, y
|
||
the computed values for @var{x} and @var{y}. They are evaluated for
|
||
each new frame.
|
||
|
||
@item in_w, in_h
|
||
the input width and height
|
||
|
||
@item iw, ih
|
||
same as @var{in_w} and @var{in_h}
|
||
|
||
@item out_w, out_h
|
||
the output (cropped) width and height
|
||
|
||
@item ow, oh
|
||
same as @var{out_w} and @var{out_h}
|
||
|
||
@item a
|
||
same as @var{iw} / @var{ih}
|
||
|
||
@item sar
|
||
input sample aspect ratio
|
||
|
||
@item dar
|
||
input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
|
||
|
||
@item hsub, vsub
|
||
horizontal and vertical chroma subsample values. For example for the
|
||
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
||
|
||
@item n
|
||
the number of input frame, starting from 0
|
||
|
||
@item 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 deshake
|
||
|
||
Attempt to fix small changes in horizontal and/or vertical shift. This
|
||
filter helps remove camera shake from hand-holding a camera, bumping a
|
||
tripod, moving on a vehicle, etc.
|
||
|
||
The filter accepts parameters as a string of the form
|
||
"@var{x}:@var{y}:@var{w}:@var{h}:@var{rx}:@var{ry}:@var{edge}:@var{blocksize}:@var{contrast}:@var{search}:@var{filename}"
|
||
|
||
A description of the accepted parameters follows.
|
||
|
||
@table @option
|
||
|
||
@item x, y, w, h
|
||
Specify a rectangular area where to limit the search for motion
|
||
vectors.
|
||
If desired the search for motion vectors can be limited to a
|
||
rectangular area of the frame defined by its top left corner, width
|
||
and height. These parameters have the same meaning as the drawbox
|
||
filter which can be used to visualise the position of the bounding
|
||
box.
|
||
|
||
This is useful when simultaneous movement of subjects within the frame
|
||
might be confused for camera motion by the motion vector search.
|
||
|
||
If any or all of @var{x}, @var{y}, @var{w} and @var{h} are set to -1
|
||
then the full frame is used. This allows later options to be set
|
||
without specifying the bounding box for the motion vector search.
|
||
|
||
Default - search the whole frame.
|
||
|
||
@item rx, ry
|
||
Specify the maximum extent of movement in x and y directions in the
|
||
range 0-64 pixels. Default 16.
|
||
|
||
@item edge
|
||
Specify how to generate pixels to fill blanks at the edge of the
|
||
frame. An integer from 0 to 3 as follows:
|
||
@table @option
|
||
@item 0
|
||
Fill zeroes at blank locations
|
||
@item 1
|
||
Original image at blank locations
|
||
@item 2
|
||
Extruded edge value at blank locations
|
||
@item 3
|
||
Mirrored edge at blank locations
|
||
@end table
|
||
|
||
The default setting is mirror edge at blank locations.
|
||
|
||
@item blocksize
|
||
Specify the blocksize to use for motion search. Range 4-128 pixels,
|
||
default 8.
|
||
|
||
@item contrast
|
||
Specify the contrast threshold for blocks. Only blocks with more than
|
||
the specified contrast (difference between darkest and lightest
|
||
pixels) will be considered. Range 1-255, default 125.
|
||
|
||
@item search
|
||
Specify the search strategy 0 = exhaustive search, 1 = less exhaustive
|
||
search. Default - exhaustive search.
|
||
|
||
@item filename
|
||
If set then a detailed log of the motion search is written to the
|
||
specified file.
|
||
|
||
@end table
|
||
|
||
@section drawbox
|
||
|
||
Draw a colored box on the input image.
|
||
|
||
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 FFmpeg 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 expressions which specify the offsets where text will be drawn
|
||
within the video frame. They are relative to the top/left border of the
|
||
output image.
|
||
|
||
The default value of @var{x} and @var{y} is "0".
|
||
|
||
See below for the list of accepted constants.
|
||
|
||
@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
|
||
|
||
The parameters for @var{x} and @var{y} are expressions containing the
|
||
following constants:
|
||
|
||
@table @option
|
||
@item W, H
|
||
the input width and height
|
||
|
||
@item tw, text_w
|
||
the width of the rendered text
|
||
|
||
@item th, text_h
|
||
the height of the rendered text
|
||
|
||
@item lh, line_h
|
||
the height of each text line
|
||
|
||
@item sar
|
||
input sample aspect ratio
|
||
|
||
@item dar
|
||
input display aspect ratio, it is the same as (@var{w} / @var{h}) * @var{sar}
|
||
|
||
@item hsub, vsub
|
||
horizontal and vertical chroma subsample values. For example for the
|
||
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
||
|
||
@item max_glyph_w
|
||
maximum glyph width, that is the maximum width for all the glyphs
|
||
contained in the rendered text
|
||
|
||
@item max_glyph_h
|
||
maximum glyph height, that is the maximum height for all the glyphs
|
||
contained in the rendered text, it is equivalent to @var{ascent} -
|
||
@var{descent}.
|
||
|
||
@item max_glyph_a, ascent
|
||
|
||
the maximum distance from the baseline to the highest/upper grid
|
||
coordinate used to place a glyph outline point, for all the rendered
|
||
glyphs.
|
||
It is a positive value, due to the grid's orientation with the Y axis
|
||
upwards.
|
||
|
||
@item max_glyph_d, descent
|
||
the maximum distance from the baseline to the lowest grid coordinate
|
||
used to place a glyph outline point, for all the rendered glyphs.
|
||
This is a negative value, due to the grid's orientation, with the Y axis
|
||
upwards.
|
||
|
||
@item n
|
||
the number of input frame, starting from 0
|
||
|
||
@item t
|
||
timestamp expressed in seconds, NAN if the input timestamp is unknown
|
||
|
||
@item timecode
|
||
initial timecode representation in "hh:mm:ss[:;.]ff" format. It can be used
|
||
with or without text parameter. @var{rate} option must be specified.
|
||
|
||
@item r, rate
|
||
frame rate (timecode only)
|
||
@end table
|
||
|
||
Some examples follow.
|
||
|
||
@itemize
|
||
|
||
@item
|
||
Draw "Test Text" with font FreeSerif, using the default values for the
|
||
optional parameters.
|
||
|
||
@example
|
||
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text'"
|
||
@end example
|
||
|
||
@item
|
||
Draw 'Test Text' with font FreeSerif of size 24 at position x=100
|
||
and y=50 (counting from the top-left corner of the screen), text is
|
||
yellow with a red box around it. Both the text and the box have an
|
||
opacity of 20%.
|
||
|
||
@example
|
||
drawtext="fontfile=/usr/share/fonts/truetype/freefont/FreeSerif.ttf: text='Test Text':\
|
||
x=100: y=50: fontsize=24: fontcolor=yellow@@0.2: box=1: boxcolor=red@@0.2"
|
||
@end example
|
||
|
||
Note that the double quotes are not necessary if spaces are not used
|
||
within the parameter list.
|
||
|
||
@item
|
||
Show the text at the center of the video frame:
|
||
@example
|
||
drawtext=fontsize=30:fontfile=FreeSerif.ttf:text='hello world':x=(w-text_w)/2:y=(h-text_h-line_h)/2"
|
||
@end example
|
||
|
||
@item
|
||
Show a text line sliding from right to left in the last row of the video
|
||
frame. The file @file{LONG_LINE} is assumed to contain a single line
|
||
with no newlines.
|
||
@example
|
||
drawtext=fontsize=15:fontfile=FreeSerif.ttf:text=LONG_LINE:y=h-line_h:x=-50*t
|
||
@end example
|
||
|
||
@item
|
||
Show the content of file @file{CREDITS} off the bottom of the frame and scroll up.
|
||
@example
|
||
drawtext=fontsize=20:fontfile=FreeSerif.ttf:textfile=CREDITS:y=h-20*t"
|
||
@end example
|
||
|
||
@item
|
||
Draw a single green letter "g", at the center of the input video.
|
||
The glyph baseline is placed at half screen height.
|
||
@example
|
||
drawtext=fontsize=60:fontfile=FreeSerif.ttf:fontcolor=green:text=g:x=(w-max_glyph_w)/2:y=h/2-ascent
|
||
@end example
|
||
|
||
@end itemize
|
||
|
||
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{options}]
|
||
|
||
@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.
|
||
|
||
@var{options} is an optional sequence of @var{key}=@var{value} pairs,
|
||
separated by ":". The description of the accepted options follows.
|
||
|
||
@table @option
|
||
|
||
@item type, t
|
||
See @var{type}.
|
||
|
||
@item start_frame, s
|
||
See @var{start_frame}.
|
||
|
||
@item nb_frames, n
|
||
See @var{nb_frames}.
|
||
|
||
@item alpha
|
||
If set to 1, fade only alpha channel, if one exists on the input.
|
||
Default value is 0.
|
||
@end table
|
||
|
||
A few usage examples follow, usable too as test scenarios.
|
||
@example
|
||
# fade in first 30 frames of video
|
||
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
|
||
|
||
# fade in alpha over first 25 frames of video
|
||
fade=in:0:25:alpha=1
|
||
@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
|
||
ffmpeg -i in.vob -vf "fieldorder=bff" out.dv
|
||
@end example
|
||
|
||
@section fifo
|
||
|
||
Buffer input images and send them when they are requested.
|
||
|
||
This filter is mainly useful when auto-inserted by the libavfilter
|
||
framework.
|
||
|
||
The filter does not take parameters.
|
||
|
||
@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
|
||
|
||
@anchor{frei0r}
|
||
@section frei0r
|
||
|
||
Apply a frei0r effect to the input video.
|
||
|
||
To enable compilation of this filter you need to install the frei0r
|
||
header and configure FFmpeg with @code{--enable-frei0r}.
|
||
|
||
The filter supports the syntax:
|
||
@example
|
||
@var{filter_name}[@{:|=@}@var{param1}:@var{param2}:...:@var{paramN}]
|
||
@end example
|
||
|
||
@var{filter_name} is the name 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 color depth.
|
||
Interpolate the gradients that should go where the bands are, and
|
||
dither them.
|
||
|
||
This filter is designed for playback only. Do not use it prior to
|
||
lossy compression, because compression tends to lose the dither and
|
||
bring back the bands.
|
||
|
||
The filter 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{ffmpeg}:
|
||
@example
|
||
ffmpeg -i in.avi -vf "hflip" out.avi
|
||
@end example
|
||
|
||
@section hqdn3d
|
||
|
||
High precision/quality 3d denoise filter. This filter aims to reduce
|
||
image noise producing smooth images and making still images really
|
||
still. It should enhance compressibility.
|
||
|
||
It accepts the following optional parameters:
|
||
@var{luma_spatial}:@var{chroma_spatial}:@var{luma_tmp}:@var{chroma_tmp}
|
||
|
||
@table @option
|
||
@item luma_spatial
|
||
a non-negative float number which specifies spatial luma strength,
|
||
defaults to 4.0
|
||
|
||
@item chroma_spatial
|
||
a non-negative float number which specifies spatial chroma strength,
|
||
defaults to 3.0*@var{luma_spatial}/4.0
|
||
|
||
@item luma_tmp
|
||
a float number which specifies luma temporal strength, defaults to
|
||
6.0*@var{luma_spatial}/4.0
|
||
|
||
@item chroma_tmp
|
||
a float number which specifies chroma temporal strength, defaults to
|
||
@var{luma_tmp}*@var{chroma_spatial}/@var{luma_spatial}
|
||
@end table
|
||
|
||
@section lut, lutrgb, lutyuv
|
||
|
||
Compute a look-up table for binding each pixel component input value
|
||
to an output value, and apply it to input video.
|
||
|
||
@var{lutyuv} applies a lookup table to a YUV input video, @var{lutrgb}
|
||
to an RGB input video.
|
||
|
||
These filters accept in input a ":"-separated list of options, which
|
||
specify the expressions used for computing the lookup table for the
|
||
corresponding pixel component values.
|
||
|
||
The @var{lut} filter requires either YUV or RGB pixel formats in
|
||
input, and accepts the options:
|
||
@table @option
|
||
@item c0
|
||
first pixel component
|
||
@item c1
|
||
second pixel component
|
||
@item c2
|
||
third pixel component
|
||
@item c3
|
||
fourth pixel component, corresponds to the alpha component
|
||
@end table
|
||
|
||
The exact component associated to each option depends on the format in
|
||
input.
|
||
|
||
The @var{lutrgb} filter requires RGB pixel formats in input, and
|
||
accepts the options:
|
||
@table @option
|
||
@item r
|
||
red component
|
||
@item g
|
||
green component
|
||
@item b
|
||
blue component
|
||
@item a
|
||
alpha component
|
||
@end table
|
||
|
||
The @var{lutyuv} filter requires YUV pixel formats in input, and
|
||
accepts the options:
|
||
@table @option
|
||
@item y
|
||
Y/luminance component
|
||
@item u
|
||
U/Cb component
|
||
@item v
|
||
V/Cr component
|
||
@item a
|
||
alpha component
|
||
@end table
|
||
|
||
The expressions can contain the following constants and functions:
|
||
|
||
@table @option
|
||
@item w, h
|
||
the input width and height
|
||
|
||
@item val
|
||
input value for the pixel component
|
||
|
||
@item clipval
|
||
the input value clipped in the @var{minval}-@var{maxval} range
|
||
|
||
@item maxval
|
||
maximum value for the pixel component
|
||
|
||
@item minval
|
||
minimum value for the pixel component
|
||
|
||
@item negval
|
||
the negated value for the pixel component value clipped in the
|
||
@var{minval}-@var{maxval} range , it corresponds to the expression
|
||
"maxval-clipval+minval"
|
||
|
||
@item clip(val)
|
||
the computed value in @var{val} clipped in the
|
||
@var{minval}-@var{maxval} range
|
||
|
||
@item gammaval(gamma)
|
||
the computed gamma correction value of the pixel component value
|
||
clipped in the @var{minval}-@var{maxval} range, corresponds to the
|
||
expression
|
||
"pow((clipval-minval)/(maxval-minval)\,@var{gamma})*(maxval-minval)+minval"
|
||
|
||
@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=y=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 mp
|
||
|
||
Apply an MPlayer filter to the input video.
|
||
|
||
This filter provides a wrapper around most of the filters of
|
||
MPlayer/MEncoder.
|
||
|
||
This wrapper is considered experimental. Some of the wrapped filters
|
||
may not work properly and we may drop support for them, as they will
|
||
be implemented natively into FFmpeg. Thus you should avoid
|
||
depending on them when writing portable scripts.
|
||
|
||
The filters accepts the parameters:
|
||
@var{filter_name}[:=]@var{filter_params}
|
||
|
||
@var{filter_name} is the name of a supported MPlayer filter,
|
||
@var{filter_params} is a string containing the parameters accepted by
|
||
the named filter.
|
||
|
||
The list of the currently supported filters follows:
|
||
@table @var
|
||
@item 2xsai
|
||
@item decimate
|
||
@item denoise3d
|
||
@item detc
|
||
@item dint
|
||
@item divtc
|
||
@item down3dright
|
||
@item dsize
|
||
@item eq2
|
||
@item eq
|
||
@item field
|
||
@item fil
|
||
@item fixpts
|
||
@item framestep
|
||
@item fspp
|
||
@item geq
|
||
@item harddup
|
||
@item hqdn3d
|
||
@item hue
|
||
@item il
|
||
@item ilpack
|
||
@item ivtc
|
||
@item kerndeint
|
||
@item mcdeint
|
||
@item mirror
|
||
@item noise
|
||
@item ow
|
||
@item palette
|
||
@item perspective
|
||
@item phase
|
||
@item pp7
|
||
@item pullup
|
||
@item qp
|
||
@item rectangle
|
||
@item remove-logo
|
||
@item rotate
|
||
@item sab
|
||
@item screenshot
|
||
@item smartblur
|
||
@item softpulldown
|
||
@item softskip
|
||
@item spp
|
||
@item telecine
|
||
@item tile
|
||
@item tinterlace
|
||
@item unsharp
|
||
@item uspp
|
||
@item yuvcsp
|
||
@item yvu9
|
||
@end table
|
||
|
||
The parameter syntax and behavior for the listed filters are the same
|
||
of the corresponding MPlayer filters. For detailed instructions check
|
||
the "VIDEO FILTERS" section in the MPlayer manual.
|
||
|
||
Some examples follow:
|
||
@example
|
||
# remove a logo by interpolating the surrounding pixels
|
||
mp=delogo=200:200:80:20:1
|
||
|
||
# adjust gamma, brightness, contrast
|
||
mp=eq2=1.0:2:0.5
|
||
|
||
# tweak hue and saturation
|
||
mp=hue=100:-10
|
||
@end example
|
||
|
||
See also mplayer(1), @url{http://www.mplayerhq.hu/}.
|
||
|
||
@section negate
|
||
|
||
Negate input video.
|
||
|
||
This filter accepts an integer in input, if non-zero it negates the
|
||
alpha component (if available). The default value in input is 0.
|
||
|
||
@section noformat
|
||
|
||
Force libavfilter not to use any of the specified pixel formats for the
|
||
input to the next filter.
|
||
|
||
The filter accepts a list of pixel format names, separated by ":",
|
||
for example "yuv420p:monow:rgb24".
|
||
|
||
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 FFmpeg with @code{--enable-libopencv}.
|
||
|
||
The filter takes the parameters: @var{filter_name}@{:=@}@var{filter_params}.
|
||
|
||
@var{filter_name} is the name of the libopencv filter to apply.
|
||
|
||
@var{filter_params} specifies the parameters to pass to the libopencv
|
||
filter. If not specified the default values are assumed.
|
||
|
||
Refer to the official libopencv documentation for more precise
|
||
information:
|
||
@url{http://opencv.willowgarage.com/documentation/c/image_filtering.html}
|
||
|
||
Follows the list of supported libopencv filters.
|
||
|
||
@anchor{dilate}
|
||
@subsection dilate
|
||
|
||
Dilate an image by using a specific structuring element.
|
||
This filter corresponds to the libopencv function @code{cvDilate}.
|
||
|
||
It accepts the parameters: @var{struct_el}:@var{nb_iterations}.
|
||
|
||
@var{struct_el} represents a structuring element, and has the syntax:
|
||
@var{cols}x@var{rows}+@var{anchor_x}x@var{anchor_y}/@var{shape}
|
||
|
||
@var{cols} and @var{rows} represent the number of columns and rows of
|
||
the structuring element, @var{anchor_x} and @var{anchor_y} the anchor
|
||
point, and @var{shape} the shape for the structuring element, and
|
||
can be one of the values "rect", "cross", "ellipse", "custom".
|
||
|
||
If the value for @var{shape} is "custom", it must be followed by a
|
||
string of the form "=@var{filename}". The file with name
|
||
@var{filename} is assumed to represent a binary image, with each
|
||
printable character corresponding to a bright pixel. When a custom
|
||
@var{shape} is used, @var{cols} and @var{rows} are ignored, the number
|
||
or columns and rows of the read file are assumed instead.
|
||
|
||
The default value for @var{struct_el} is "3x3+0x0/rect".
|
||
|
||
@var{nb_iterations} specifies the number of times the transform is
|
||
applied to the image, and defaults to 1.
|
||
|
||
Follow some example:
|
||
@example
|
||
# use the default values
|
||
ocv=dilate
|
||
|
||
# dilate using a structuring element with a 5x5 cross, iterate two times
|
||
ocv=dilate=5x5+2x2/cross:2
|
||
|
||
# read the shape from the file diamond.shape, iterate two times
|
||
# the file diamond.shape may contain a pattern of characters like this:
|
||
# *
|
||
# ***
|
||
# *****
|
||
# ***
|
||
# *
|
||
# the specified cols and rows are ignored (but not the anchor point coordinates)
|
||
ocv=0x0+2x2/custom=diamond.shape:2
|
||
@end example
|
||
|
||
@subsection erode
|
||
|
||
Erode an image by using a specific structuring element.
|
||
This filter corresponds to the libopencv function @code{cvErode}.
|
||
|
||
The filter accepts the parameters: @var{struct_el}:@var{nb_iterations},
|
||
with the same syntax and semantics as the @ref{dilate} filter.
|
||
|
||
@subsection smooth
|
||
|
||
Smooth the input video.
|
||
|
||
The filter takes the following parameters:
|
||
@var{type}:@var{param1}:@var{param2}:@var{param3}:@var{param4}.
|
||
|
||
@var{type} is the type of smooth filter to apply, and can be one of
|
||
the following values: "blur", "blur_no_scale", "median", "gaussian",
|
||
"bilateral". The default value is "gaussian".
|
||
|
||
@var{param1}, @var{param2}, @var{param3}, and @var{param4} are
|
||
parameters whose meanings depend on smooth type. @var{param1} and
|
||
@var{param2} accept integer positive values or 0, @var{param3} and
|
||
@var{param4} accept float values.
|
||
|
||
The default value for @var{param1} is 3, the default value for the
|
||
other parameters is 0.
|
||
|
||
These parameters correspond to the parameters assigned to the
|
||
libopencv function @code{cvSmooth}.
|
||
|
||
@anchor{overlay}
|
||
@section overlay
|
||
|
||
Overlay one video on top of another.
|
||
|
||
It takes two inputs and one output, the first input is the "main"
|
||
video on which the second input is overlayed.
|
||
|
||
It accepts the parameters: @var{x}:@var{y}[:@var{options}].
|
||
|
||
@var{x} is the x coordinate of the overlayed video on the main video,
|
||
@var{y} is the y coordinate. @var{x} and @var{y} 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
|
||
|
||
@var{options} is an optional list of @var{key}=@var{value} pairs,
|
||
separated by ":".
|
||
|
||
The description of the accepted options follows.
|
||
|
||
@table @option
|
||
@item rgb
|
||
If set to 1, force the filter to accept inputs in the RGB
|
||
color space. Default value is 0.
|
||
@end table
|
||
|
||
Be aware that frames are taken from each input video in timestamp
|
||
order, hence, if their initial timestamps differ, it is a a good idea
|
||
to pass the two inputs through a @var{setpts=PTS-STARTPTS} filter to
|
||
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
|
||
movie=logo.png [logo];
|
||
[in][logo] overlay=10:main_h-overlay_h-10 [out]
|
||
|
||
# insert 2 different transparent PNG logos (second logo on bottom
|
||
# right corner):
|
||
movie=logo1.png [logo1];
|
||
movie=logo2.png [logo2];
|
||
[in][logo1] overlay=10:H-h-10 [in+logo1];
|
||
[in+logo1][logo2] overlay=W-w-10:H-h-10 [out]
|
||
|
||
# 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 in_w, in_h
|
||
the input video width and height
|
||
|
||
@item iw, ih
|
||
same as @var{in_w} and @var{in_h}
|
||
|
||
@item out_w, out_h
|
||
the output width and height, that is the size of the padded area as
|
||
specified by the @var{width} and @var{height} expressions
|
||
|
||
@item ow, oh
|
||
same as @var{out_w} and @var{out_h}
|
||
|
||
@item x, y
|
||
x and y offsets as specified by the @var{x} and @var{y}
|
||
expressions, or NAN if not yet specified
|
||
|
||
@item a
|
||
same as @var{iw} / @var{ih}
|
||
|
||
@item sar
|
||
input sample aspect ratio
|
||
|
||
@item dar
|
||
input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
|
||
|
||
@item hsub, vsub
|
||
horizontal and vertical chroma subsample values. For example for the
|
||
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
||
@end table
|
||
|
||
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"
|
||
|
||
# for anamorphic video, in order to set the output display aspect ratio,
|
||
# it is necessary to use sar in the expression, according to the relation:
|
||
# (ih * X / ih) * sar = output_dar
|
||
# X = output_dar / sar
|
||
pad="ih*16/9/sar: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}[:@var{interl}=@{1|-1@}] and/or convert the image format.
|
||
|
||
The scale filter forces the output display aspect ratio to be the same
|
||
of the input, by changing the output sample aspect ratio.
|
||
|
||
The parameters @var{width} and @var{height} are expressions containing
|
||
the following constants:
|
||
|
||
@table @option
|
||
@item in_w, in_h
|
||
the input width and height
|
||
|
||
@item iw, ih
|
||
same as @var{in_w} and @var{in_h}
|
||
|
||
@item out_w, out_h
|
||
the output (cropped) width and height
|
||
|
||
@item ow, oh
|
||
same as @var{out_w} and @var{out_h}
|
||
|
||
@item a
|
||
same as @var{iw} / @var{ih}
|
||
|
||
@item sar
|
||
input sample aspect ratio
|
||
|
||
@item dar
|
||
input display aspect ratio, it is the same as (@var{iw} / @var{ih}) * @var{sar}
|
||
|
||
@item hsub, vsub
|
||
horizontal and vertical chroma subsample values. For example for the
|
||
pixel format "yuv422p" @var{hsub} is 2 and @var{vsub} is 1.
|
||
@end table
|
||
|
||
If the input image format is different from the format requested by
|
||
the next filter, the scale filter will convert the input to the
|
||
requested format.
|
||
|
||
If the value for @var{width} or @var{height} is 0, the respective input
|
||
size is used for the output.
|
||
|
||
If the value for @var{width} or @var{height} is -1, the scale filter will
|
||
use, for the respective output size, a value that maintains the aspect
|
||
ratio of the input image.
|
||
|
||
The default value of @var{width} and @var{height} is 0.
|
||
|
||
Valid values for the optional parameter @var{interl} are:
|
||
|
||
@table @option
|
||
@item 1
|
||
force interlaced aware scaling
|
||
|
||
@item -1
|
||
select interlaced aware scaling depending on whether the source frames
|
||
are flagged as interlaced or not
|
||
@end table
|
||
|
||
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 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
|
||
|
||
@section setdar, setsar
|
||
|
||
The @code{setdar} filter sets the Display Aspect Ratio for the filter
|
||
output video.
|
||
|
||
This is done by changing the specified Sample (aka Pixel) Aspect
|
||
Ratio, according to the following equation:
|
||
@example
|
||
@var{DAR} = @var{HORIZONTAL_RESOLUTION} / @var{VERTICAL_RESOLUTION} * @var{SAR}
|
||
@end example
|
||
|
||
Keep in mind that the @code{setdar} filter does not modify the pixel
|
||
dimensions of the video frame. Also the display aspect ratio set by
|
||
this filter may be changed by later filters in the filterchain,
|
||
e.g. in case of scaling or if another "setdar" or a "setsar" filter is
|
||
applied.
|
||
|
||
The @code{setsar} filter sets the Sample (aka Pixel) Aspect Ratio for
|
||
the filter output video.
|
||
|
||
Note that as a consequence of the application of this filter, the
|
||
output display aspect ratio will change according to the equation
|
||
above.
|
||
|
||
Keep in mind that the sample aspect ratio set by the @code{setsar}
|
||
filter may be changed by later filters in the filterchain, e.g. if
|
||
another "setsar" or a "setdar" filter is applied.
|
||
|
||
The @code{setdar} and @code{setsar} filters accept a parameter string
|
||
which represents the wanted aspect ratio. The parameter can
|
||
be a floating point number string, an expression, or a string of the form
|
||
@var{num}:@var{den}, where @var{num} and @var{den} are the numerator
|
||
and denominator of the aspect ratio. If the parameter is not
|
||
specified, it is assumed the value "0:1".
|
||
|
||
For example to change the display aspect ratio to 16:9, specify:
|
||
@example
|
||
setdar=16:9
|
||
@end example
|
||
|
||
The example above is equivalent to:
|
||
@example
|
||
setdar=1.77777
|
||
@end example
|
||
|
||
To change the sample aspect ratio to 10:11, specify:
|
||
@example
|
||
setsar=10:11
|
||
@end example
|
||
|
||
@section setfield
|
||
|
||
Force field for the output video frame.
|
||
|
||
The @code{setfield} filter marks the interlace type field for the
|
||
output frames. It does not change the input frame, but only sets the
|
||
corresponding property, which affects how the frame is treated by
|
||
followig filters (e.g. @code{fieldorder} or @code{yadif}).
|
||
|
||
It accepts a parameter representing an integer or a string, which can
|
||
assume the following values:
|
||
@table @samp
|
||
@item -1, auto
|
||
Keep the same field property.
|
||
|
||
@item 0, bff
|
||
Mark the frame as bottom-field-first.
|
||
|
||
@item 1, tff
|
||
Mark the frame as top-field-first.
|
||
@end table
|
||
|
||
@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 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
|
||
|
||
@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 "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 (printed in hexadecimal) of all the planes of the input frame
|
||
|
||
@item plane_checksum
|
||
Adler-32 checksum (printed in hexadecimal) of each plane of the input frame,
|
||
expressed in the form "[@var{c0} @var{c1} @var{c2} @var{c3}]"
|
||
@end table
|
||
|
||
@section slicify
|
||
|
||
Pass the images of input video on to next video filter as multiple
|
||
slices.
|
||
|
||
@example
|
||
ffmpeg -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
|
||
|
||
Pass on the input video to two outputs. Both outputs are identical to
|
||
the input video.
|
||
|
||
For example:
|
||
@example
|
||
[in] split [splitout1][splitout2];
|
||
[splitout1] crop=100:100:0:0 [cropout];
|
||
[splitout2] pad=200:200:100:100 [padout];
|
||
@end example
|
||
|
||
will create two separate outputs from the same input, one cropped and
|
||
one padded.
|
||
|
||
@section swapuv
|
||
Swap U & V plane.
|
||
|
||
@section thumbnail
|
||
Select the most representative frame in a given sequence of consecutive frames.
|
||
|
||
It accepts as argument the frames batch size to analyze (default @var{N}=100);
|
||
in a set of @var{N} frames, the filter will pick one of them, and then handle
|
||
the next batch of @var{N} frames until the end.
|
||
|
||
Since the filter keeps track of the whole frames sequence, a bigger @var{N}
|
||
value will result in a higher memory usage, so a high value is not recommended.
|
||
|
||
The following example extract one picture each 50 frames:
|
||
@example
|
||
thumbnail=50
|
||
@end example
|
||
|
||
Complete example of a thumbnail creation with @command{ffmpeg}:
|
||
@example
|
||
ffmpeg -i in.avi -vf thumbnail,scale=300:200 -frames:v 1 out.png
|
||
@end example
|
||
|
||
@section tile
|
||
|
||
Tile several successive frames together.
|
||
|
||
It accepts as argument the tile size (i.e. the number of lines and columns)
|
||
in the form "@var{w}x@var{h}".
|
||
|
||
For example, produce 8×8 PNG tiles of all keyframes (@option{-skip_frame
|
||
nokey}) in a movie:
|
||
@example
|
||
ffmpeg -skip_frame nokey -i file.avi -vf 'scale=128:72,tile=8x8' -an -vsync 0 keyframes%03d.png
|
||
@end example
|
||
The @option{-vsync 0} is necessary to prevent @command{ffmpeg} from
|
||
duplicating each output frame to accomodate the originally detected frame
|
||
rate.
|
||
|
||
@section tinterlace
|
||
|
||
Perform various types of temporal field interlacing.
|
||
|
||
Frames are counted starting from 1, so the first input frame is
|
||
considered odd.
|
||
|
||
This filter accepts a single parameter specifying the mode. Available
|
||
modes are:
|
||
|
||
@table @samp
|
||
@item 0
|
||
Move odd frames into the upper field, even into the lower field,
|
||
generating a double height frame at half framerate.
|
||
|
||
@item 1
|
||
Only output even frames, odd frames are dropped, generating a frame with
|
||
unchanged height at half framerate.
|
||
|
||
@item 2
|
||
Only output odd frames, even frames are dropped, generating a frame with
|
||
unchanged height at half framerate.
|
||
|
||
@item 3
|
||
Expand each frame to full height, but pad alternate lines with black,
|
||
generating a frame with double height at the same input framerate.
|
||
|
||
@item 4
|
||
Interleave the upper field from odd frames with the lower field from
|
||
even frames, generating a frame with unchanged height at half framerate.
|
||
|
||
@item 5
|
||
Interleave the lower field from odd frames with the upper field from
|
||
even frames, generating a frame with unchanged height at half framerate.
|
||
@end table
|
||
|
||
Default mode is 0.
|
||
|
||
@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 chroma_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{ffmpeg}
|
||
ffmpeg -i in.avi -vf "unsharp" out.mp4
|
||
@end example
|
||
|
||
@section vflip
|
||
|
||
Flip the input video vertically.
|
||
|
||
@example
|
||
ffmpeg -i in.avi -vf "vflip" out.avi
|
||
@end example
|
||
|
||
@section yadif
|
||
|
||
Deinterlace the input video ("yadif" means "yet another deinterlacing
|
||
filter").
|
||
|
||
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}:@var{scale_params}
|
||
|
||
All the parameters but @var{scale_params} 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.
|
||
|
||
@item scale_params
|
||
Specify the optional parameters to be used for the scale filter which
|
||
is automatically inserted when an input change is detected in the
|
||
input size or format.
|
||
@end table
|
||
|
||
For example:
|
||
@example
|
||
buffer=320:240:yuv410p:1:24:1:1
|
||
@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=320:240:6:1:24:1:1
|
||
@end example
|
||
|
||
@section cellauto
|
||
|
||
Create a pattern generated by an elementary cellular automaton.
|
||
|
||
The initial state of the cellular automaton can be defined through the
|
||
@option{filename}, and @option{pattern} options. If such options are
|
||
not specified an initial state is created randomly.
|
||
|
||
At each new frame a new row in the video is filled with the result of
|
||
the cellular automaton next generation. The behavior when the whole
|
||
frame is filled is defined by the @option{scroll} option.
|
||
|
||
This source accepts a list of options in the form of
|
||
@var{key}=@var{value} pairs separated by ":". A description of the
|
||
accepted options follows.
|
||
|
||
@table @option
|
||
@item filename, f
|
||
Read the initial cellular automaton state, i.e. the starting row, from
|
||
the specified file.
|
||
In the file, each non-whitespace character is considered an alive
|
||
cell, a newline will terminate the row, and further characters in the
|
||
file will be ignored.
|
||
|
||
@item pattern, p
|
||
Read the initial cellular automaton state, i.e. the starting row, from
|
||
the specified string.
|
||
|
||
Each non-whitespace character in the string is considered an alive
|
||
cell, a newline will terminate the row, and further characters in the
|
||
string will be ignored.
|
||
|
||
@item rate, r
|
||
Set the video rate, that is the number of frames generated per second.
|
||
Default is 25.
|
||
|
||
@item random_fill_ratio, ratio
|
||
Set the random fill ratio for the initial cellular automaton row. It
|
||
is a floating point number value ranging from 0 to 1, defaults to
|
||
1/PHI.
|
||
|
||
This option is ignored when a file or a pattern is specified.
|
||
|
||
@item random_seed, seed
|
||
Set the seed for filling randomly the initial row, must be an integer
|
||
included between 0 and UINT32_MAX. If not specified, or if explicitly
|
||
set to -1, the filter will try to use a good random seed on a best
|
||
effort basis.
|
||
|
||
@item rule
|
||
Set the cellular automaton rule, it is a number ranging from 0 to 255.
|
||
Default value is 110.
|
||
|
||
@item size, s
|
||
Set the size of the output video.
|
||
|
||
If @option{filename} or @option{pattern} is specified, the size is set
|
||
by default to the width of the specified initial state row, and the
|
||
height is set to @var{width} * PHI.
|
||
|
||
If @option{size} is set, it must contain the width of the specified
|
||
pattern string, and the specified pattern will be centered in the
|
||
larger row.
|
||
|
||
If a filename or a pattern string is not specified, the size value
|
||
defaults to "320x518" (used for a randomly generated initial state).
|
||
|
||
@item scroll
|
||
If set to 1, scroll the output upward when all the rows in the output
|
||
have been already filled. If set to 0, the new generated row will be
|
||
written over the top row just after the bottom row is filled.
|
||
Defaults to 1.
|
||
|
||
@item start_full, full
|
||
If set to 1, completely fill the output with generated rows before
|
||
outputting the first frame.
|
||
This is the default behavior, for disabling set the value to 0.
|
||
|
||
@item stitch
|
||
If set to 1, stitch the left and right row edges together.
|
||
This is the default behavior, for disabling set the value to 0.
|
||
@end table
|
||
|
||
@subsection Examples
|
||
|
||
@itemize
|
||
@item
|
||
Read the initial state from @file{pattern}, and specify an output of
|
||
size 200x400.
|
||
@example
|
||
cellauto=f=pattern:s=200x400
|
||
@end example
|
||
|
||
@item
|
||
Generate a random initial row with a width of 200 cells, with a fill
|
||
ratio of 2/3:
|
||
@example
|
||
cellauto=ratio=2/3:s=200x200
|
||
@end example
|
||
|
||
@item
|
||
Create a pattern generated by rule 18 starting by a single alive cell
|
||
centered on an initial row with width 100:
|
||
@example
|
||
cellauto=p=@@:s=100x400:full=0:rule=18
|
||
@end example
|
||
|
||
@item
|
||
Specify a more elaborated initial pattern:
|
||
@example
|
||
cellauto=p='@@@@ @@ @@@@':s=100x400:full=0:rule=18
|
||
@end example
|
||
|
||
@end itemize
|
||
|
||
@section 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
|
||
@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".
|
||
|
||
@item loop
|
||
Specifies how many times to read the video stream in sequence.
|
||
If the value is less than 1, the stream will be read again and again.
|
||
Default value is "1".
|
||
|
||
Note that when the movie is looped the source timestamps are not
|
||
changed, so it will generate non monotonically increasing timestamps.
|
||
@end table
|
||
|
||
This filter allows to overlay a second video on top of main input of
|
||
a filtergraph as shown in this graph:
|
||
@example
|
||
input -----------> deltapts0 --> overlay --> output
|
||
^
|
||
|
|
||
movie --> scale--> deltapts1 -------+
|
||
@end example
|
||
|
||
Some examples follow:
|
||
@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 mptestsrc
|
||
|
||
Generate various test patterns, as generated by the MPlayer test filter.
|
||
|
||
The size of the generated video is fixed, and is 256x256.
|
||
This source is useful in particular for testing encoding features.
|
||
|
||
This source accepts an optional sequence of @var{key}=@var{value} pairs,
|
||
separated by ":". The description of the accepted options follows.
|
||
|
||
@table @option
|
||
|
||
@item rate, r
|
||
Specify the frame rate of the sourced video, as the number of frames
|
||
generated per second. It has to be a string in the format
|
||
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
|
||
number or a valid video frame rate abbreviation. The default value is
|
||
"25".
|
||
|
||
@item duration, d
|
||
Set the video duration of the sourced video. The accepted syntax is:
|
||
@example
|
||
[-]HH[:MM[:SS[.m...]]]
|
||
[-]S+[.m...]
|
||
@end example
|
||
See also the function @code{av_parse_time()}.
|
||
|
||
If not specified, or the expressed duration is negative, the video is
|
||
supposed to be generated forever.
|
||
|
||
@item test, t
|
||
|
||
Set the number or the name of the test to perform. Supported tests are:
|
||
@table @option
|
||
@item dc_luma
|
||
@item dc_chroma
|
||
@item freq_luma
|
||
@item freq_chroma
|
||
@item amp_luma
|
||
@item amp_chroma
|
||
@item cbp
|
||
@item mv
|
||
@item ring1
|
||
@item ring2
|
||
@item all
|
||
@end table
|
||
|
||
Default value is "all", which will cycle through the list of all tests.
|
||
@end table
|
||
|
||
For example the following:
|
||
@example
|
||
testsrc=t=dc_luma
|
||
@end example
|
||
|
||
will generate a "dc_luma" test pattern.
|
||
|
||
@section frei0r_src
|
||
|
||
Provide a frei0r source.
|
||
|
||
To enable compilation of this filter you need to install the frei0r
|
||
header and configure FFmpeg with @code{--enable-frei0r}.
|
||
|
||
The source supports the syntax:
|
||
@example
|
||
@var{size}:@var{rate}:@var{src_name}[@{=|:@}@var{param1}:@var{param2}:...:@var{paramN}]
|
||
@end example
|
||
|
||
@var{size} is the size of the video to generate, may be a string of the
|
||
form @var{width}x@var{height} or a frame size abbreviation.
|
||
@var{rate} is the rate of the video to generate, may be a string of
|
||
the form @var{num}/@var{den} or a frame rate abbreviation.
|
||
@var{src_name} is the name to the frei0r source to load. For more
|
||
information regarding frei0r and how to set the parameters read the
|
||
section @ref{frei0r} in the description of the video filters.
|
||
|
||
Some examples follow:
|
||
@example
|
||
# generate a frei0r partik0l source with size 200x200 and frame rate 10
|
||
# which is overlayed on the overlay filter main input
|
||
frei0r_src=200x200:10:partik0l=1234 [overlay]; [in][overlay] overlay
|
||
@end example
|
||
|
||
@section life
|
||
|
||
Generate a life pattern.
|
||
|
||
This source is based on a generalization of John Conway's life game.
|
||
|
||
The sourced input represents a life grid, each pixel represents a cell
|
||
which can be in one of two possible states, alive or dead. Every cell
|
||
interacts with its eight neighbours, which are the cells that are
|
||
horizontally, vertically, or diagonally adjacent.
|
||
|
||
At each interaction the grid evolves according to the adopted rule,
|
||
which specifies the number of neighbor alive cells which will make a
|
||
cell stay alive or born. The @option{rule} option allows to specify
|
||
the rule to adopt.
|
||
|
||
This source accepts a list of options in the form of
|
||
@var{key}=@var{value} pairs separated by ":". A description of the
|
||
accepted options follows.
|
||
|
||
@table @option
|
||
@item filename, f
|
||
Set the file from which to read the initial grid state. In the file,
|
||
each non-whitespace character is considered an alive cell, and newline
|
||
is used to delimit the end of each row.
|
||
|
||
If this option is not specified, the initial grid is generated
|
||
randomly.
|
||
|
||
@item rate, r
|
||
Set the video rate, that is the number of frames generated per second.
|
||
Default is 25.
|
||
|
||
@item random_fill_ratio, ratio
|
||
Set the random fill ratio for the initial random grid. It is a
|
||
floating point number value ranging from 0 to 1, defaults to 1/PHI.
|
||
It is ignored when a file is specified.
|
||
|
||
@item random_seed, seed
|
||
Set the seed for filling the initial random grid, must be an integer
|
||
included between 0 and UINT32_MAX. If not specified, or if explicitly
|
||
set to -1, the filter will try to use a good random seed on a best
|
||
effort basis.
|
||
|
||
@item rule
|
||
Set the life rule.
|
||
|
||
A rule can be specified with a code of the kind "S@var{NS}/B@var{NB}",
|
||
where @var{NS} and @var{NB} are sequences of numbers in the range 0-8,
|
||
@var{NS} specifies the number of alive neighbor cells which make a
|
||
live cell stay alive, and @var{NB} the number of alive neighbor cells
|
||
which make a dead cell to become alive (i.e. to "born").
|
||
"s" and "b" can be used in place of "S" and "B", respectively.
|
||
|
||
Alternatively a rule can be specified by an 18-bits integer. The 9
|
||
high order bits are used to encode the next cell state if it is alive
|
||
for each number of neighbor alive cells, the low order bits specify
|
||
the rule for "borning" new cells. Higher order bits encode for an
|
||
higher number of neighbor cells.
|
||
For example the number 6153 = @code{(12<<9)+9} specifies a stay alive
|
||
rule of 12 and a born rule of 9, which corresponds to "S23/B03".
|
||
|
||
Default value is "S23/B3", which is the original Conway's game of life
|
||
rule, and will keep a cell alive if it has 2 or 3 neighbor alive
|
||
cells, and will born a new cell if there are three alive cells around
|
||
a dead cell.
|
||
|
||
@item size, s
|
||
Set the size of the output video.
|
||
|
||
If @option{filename} is specified, the size is set by default to the
|
||
same size of the input file. If @option{size} is set, it must contain
|
||
the size specified in the input file, and the initial grid defined in
|
||
that file is centered in the larger resulting area.
|
||
|
||
If a filename is not specified, the size value defaults to "320x240"
|
||
(used for a randomly generated initial grid).
|
||
|
||
@item stitch
|
||
If set to 1, stitch the left and right grid edges together, and the
|
||
top and bottom edges also. Defaults to 1.
|
||
|
||
@item mold
|
||
Set cell mold speed. If set, a dead cell will go from @option{death_color} to
|
||
@option{mold_color} with a step of @option{mold}. @option{mold} can have a
|
||
value from 0 to 255.
|
||
|
||
@item life_color
|
||
Set the color of living (or new born) cells.
|
||
|
||
@item death_color
|
||
Set the color of dead cells. If @option{mold} is set, this is the first color
|
||
used to represent a dead cell.
|
||
|
||
@item mold_color
|
||
Set mold color, for definitely dead and moldy cells.
|
||
@end table
|
||
|
||
@subsection Examples
|
||
|
||
@itemize
|
||
@item
|
||
Read a grid from @file{pattern}, and center it on a grid of size
|
||
300x300 pixels:
|
||
@example
|
||
life=f=pattern:s=300x300
|
||
@end example
|
||
|
||
@item
|
||
Generate a random grid of size 200x200, with a fill ratio of 2/3:
|
||
@example
|
||
life=ratio=2/3:s=200x200
|
||
@end example
|
||
|
||
@item
|
||
Specify a custom rule for evolving a randomly generated grid:
|
||
@example
|
||
life=rule=S14/B34
|
||
@end example
|
||
|
||
@item
|
||
Full example with slow death effect (mold) using @command{ffplay}:
|
||
@example
|
||
ffplay -f lavfi life=s=300x200:mold=10:r=60:ratio=0.1:death_color=#C83232:life_color=#00ff00,scale=1200:800:flags=16
|
||
@end example
|
||
@end itemize
|
||
|
||
@section nullsrc, rgbtestsrc, testsrc
|
||
|
||
The @code{nullsrc} source returns unprocessed video frames. It is
|
||
mainly useful to be employed in analysis / debugging tools, or as the
|
||
source for filters which ignore the input data.
|
||
|
||
The @code{rgbtestsrc} source generates an RGB test pattern useful for
|
||
detecting RGB vs BGR issues. You should see a red, green and blue
|
||
stripe from top to bottom.
|
||
|
||
The @code{testsrc} source generates a test video pattern, showing a
|
||
color pattern, a scrolling gradient and a timestamp. This is mainly
|
||
intended for testing purposes.
|
||
|
||
These sources accept an optional sequence of @var{key}=@var{value} pairs,
|
||
separated by ":". The description of the accepted options follows.
|
||
|
||
@table @option
|
||
|
||
@item size, s
|
||
Specify the size of the sourced video, it may be a string of the form
|
||
@var{width}x@var{height}, or the name of a size abbreviation. The
|
||
default value is "320x240".
|
||
|
||
@item rate, r
|
||
Specify the frame rate of the sourced video, as the number of frames
|
||
generated per second. It has to be a string in the format
|
||
@var{frame_rate_num}/@var{frame_rate_den}, an integer number, a float
|
||
number or a valid video frame rate abbreviation. The default value is
|
||
"25".
|
||
|
||
@item sar
|
||
Set the sample aspect ratio of the sourced video.
|
||
|
||
@item duration, d
|
||
Set the video duration of the sourced video. The accepted syntax is:
|
||
@example
|
||
[-]HH[:MM[:SS[.m...]]]
|
||
[-]S+[.m...]
|
||
@end example
|
||
See also the function @code{av_parse_time()}.
|
||
|
||
If not specified, or the expressed duration is negative, the video is
|
||
supposed to be generated forever.
|
||
|
||
@item decimals, n
|
||
Set the number of decimals to show in the timestamp, only used in the
|
||
@code{testsrc} source.
|
||
|
||
The displayed timestamp value will correspond to the original
|
||
timestamp value multiplied by the power of 10 of the specified
|
||
value. Default value is 0.
|
||
@end table
|
||
|
||
For example the following:
|
||
@example
|
||
testsrc=duration=5.3:size=qcif:rate=10
|
||
@end example
|
||
|
||
will generate a video with a duration of 5.3 seconds, with size
|
||
176x144 and a frame rate of 10 frames per second.
|
||
|
||
If the input content is to be ignored, @code{nullsrc} can be used. The
|
||
following command generates noise in the luminance plane by employing
|
||
the @code{mp=geq} filter:
|
||
@example
|
||
nullsrc=s=256x256, mp=geq=random(1)*255:128:128
|
||
@end example
|
||
|
||
@c man end VIDEO SOURCES
|
||
|
||
@chapter Video Sinks
|
||
@c man begin VIDEO SINKS
|
||
|
||
Below is a description of the currently available video sinks.
|
||
|
||
@section buffersink
|
||
|
||
Buffer video frames, and make them available to the end of the filter
|
||
graph.
|
||
|
||
This sink is mainly intended for a programmatic use, in particular
|
||
through the interface defined in @file{libavfilter/buffersink.h}.
|
||
|
||
It does not require a string parameter in input, but you need to
|
||
specify a pointer to a list of supported pixel formats terminated by
|
||
-1 in the opaque parameter provided to @code{avfilter_init_filter}
|
||
when initializing this sink.
|
||
|
||
@section nullsink
|
||
|
||
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
|