[MEncoder-users] Reencoding ac3 streams problem

[Peter Hartshorn]

Hello all,

I am trying to reencode the ac3 audio from a dvd to a lower bitrate ac3 stream 
with mencoder using the following command:

#  /usr/bin/mencoder dvd://1 -channels 6 -ovc frameno -oac lavc -lavcopts 
acodec=ac3:abitrate=192 -o frameno.avi -mc 0

The problem is that when frameno.avi is played back with the command:

# mplayer -channels 6 frameno.avi

The channels are wrong. I have to append "-af 
channels=6:6:0:0:4:1:2:2:1:3:3:4:5:5" to get the audio back into the right 
channels.

If I use -oac copy to extract the ac3 stream the channels are fine. Is there 
some way of getting lavc not to rearrange the channels. I have tried passing 
"-af channels=6:6:0:0:4:1:2:2:1:3:3:4:5:5" and "-af 
6:6:0:0:1:4:2:2:3:1:4:3:5:5" to mencoder but it had no effect.

Thanking you in advance
Peter Hartshorn.