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ffmpeg: add -map_channel option.

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Based on an initial work by Baptiste Coudurier.
This commit is contained in:
Clément Bœsch 2011-11-04 18:54:01 +01:00
parent 682e0eaf14
commit f5cd136f2b
15 changed files with 228 additions and 22 deletions
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38
doc/ffmpeg.texi
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@ -721,6 +721,44 @@ ffmpeg -i INPUT -map 0 -map -0:a:1 OUTPUT
Note that using this option disables the default mappings for this output file.
@item -map_channel [@var{input_file_id}.@var{stream_specifier}.@var{channel_id}|-1][:@var{output_file_id}.@var{stream_specifier}]
Map an audio channel from a given input to an output. If
@var{output_file_id}.@var{stream_specifier} are not set, the audio channel will
be mapped on all the audio streams.
Using "-1" instead of
@var{input_file_id}.@var{stream_specifier}.@var{channel_id} will map a muted
channel.
For example, assuming @var{INPUT} is a stereo audio file, you can switch the
two audio channels with the following command:
@example
ffmpeg -i INPUT -map_channel 0.0.1 -map_channel 0.0.0 OUTPUT
@end example
If you want to mute the first channel and keep the second:
@example
ffmpeg -i INPUT -map_channel -1 -map_channel 0.0.1 OUTPUT
@end example
The order of the "-map_channel" option specifies the order of the channels in
the output stream. The output channel layout is guessed from the number of
channels mapped (mono if one "-map_channel", stereo if two, etc.). Using "-ac"
in combination of "-map_channel" makes the channel gain levels to be updated if
channel layouts don't match (for instance two "-map_channel" options and "-ac
6").
You can also extract each channel of an @var{INPUT} to specific outputs; the
following command extract each channel of the audio stream (file 0, stream 0)
to the respective @var{OUTPUT_CH0} and @var{OUTPUT_CH1}:
@example
ffmpeg -i INPUT -map_channel 0.0.0 OUTPUT_CH0 -map_channel 0.0.1 OUTPUT_CH1
@end example
Note that "-map_channel" is currently limited to the scope of one input for
each output; you can't for example use it to pick multiple input audio files
and mix them into one single output.
@item -map_metadata[:@var{metadata_type}][:@var{index}] @var{infile}[:@var{metadata_type}][:@var{index}] (@emph{output,per-metadata})
Set metadata information of the next output file from @var{infile}. Note that
those are file indices (zero-based), not filenames.