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authorAlex Converse <alex.converse@gmail.com>2012-06-08 18:42:53 -0700
committerAlex Converse <alex.converse@gmail.com>2012-06-22 13:55:58 -0700
commit41e637e44902246efa17babf26e9be8a4a519e6f (patch)
treeb63208f4423f4f7475afc5e945e1d2853151881a /doc
parentdc07fb6f7b8fe0f7febdd89e21d23ac50ae920ec (diff)
lavfi: Add the af_channelmap audio channel mapping filter.
Inspired by MPlayer's af_channels filter and SoX's remix effect.
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diff --git a/doc/filters.texi b/doc/filters.texi
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@@ -232,6 +232,39 @@ front_center.wav -map '[LFE]' lfe.wav -map '[SL]' side_left.wav -map '[SR]'
side_right.wav
@end example
+@section channelmap
+Remap input channels to new locations.
+
+This filter accepts the following named parameters:
+@table @option
+@item channel_layout
+Channel layout of the output stream.
+
+@item map
+Map channels from input to output. The argument is a comma-separated list of
+mappings, each in the @code{@var{in_channel}-@var{out_channel}} or
+@var{in_channel} form. @var{in_channel} can be either the name of the input
+channel (e.g. FL for front left) or its index in the input channel layout.
+@var{out_channel} is the name of the output channel or its index in the output
+channel layout. If @var{out_channel} is not given then it is implicitly an
+index, starting with zero and increasing by one for each mapping.
+@end table
+
+If no mapping is present, the filter will implicitly map input channels to
+output channels preserving index.
+
+For example, assuming a 5.1+downmix input MOV file
+@example
+avconv -i in.mov -filter 'channelmap=map=DL-FL\,DR-FR' out.wav
+@end example
+will create an output WAV file tagged as stereo from the downmix channels of
+the input.
+
+To fix a 5.1 WAV improperly encoded in AAC's native channel order
+@example
+avconv -i in.wav -filter 'channelmap=1\,2\,0\,5\,3\,4:channel_layout=5.1' out.wav
+@end example
+
@section join
Join multiple input streams into one multi-channel stream.