[MPlayer-users] mencoder: howto strip/separate left/right audio channel

[Nico Sabbi]

On Monday 17 March 2008 17:09:51 Peter Daum wrote:
> Hi,
>
> I regularly have to deal with DVB-T recordings where 2 totally
> different audio tracks (different languages, description for
> visually impaired people, ...) are packed into the left/right
> channel of 1 stereo audio track.

disgusting

> Since most players don't have the 
> option to select only one stereo channel, the result is totally
> incomprehensible. What i am looking for is a way to either just
> drop 1 channel and create a mono sound track or (better) transform
> the left/right stereo channels into 2 separate (mono) audio tracks,
> preferably without re-encoding the data.
>
> Regarding the 1st possibility (selecting the right channel), I came
> up with:
>
> mencoder in.mpg -o out.mpg -ovc copy -oac lavc -lavcopts acodec=mp2
> -of mpeg \ -mpegopts format=dvd:vaspect=4/3:muxrate=9500 -af
> channels=2:2:1:0:1:1
>

both mencoder and mplayer support -af pan:

-af pan=1:1:1:0:0 for the left channel and -af pan=1:0:0:1:1 for the 
right one

or something like that. pan is very confusing :)