[MPlayer-users] DVD Playback sound optimisation

[Matt]

I am trying to play back DVDs on my FreeBSD box, it is a 500Mhz AMD K6-II  
with 256MB Ram and an 8MB ATi card. I am using the following as the  
command to launch MPlayer at the moment:

mplayer dvd://4 -dvd-device /cdrom -fs -lavopts lowres=1 -vfm ffmpeg -ao  
oss -vo xv -framedrop -cache 8192

I am running the latest daily snapshot from the CVS.

When I set the sound to null the video playback is perfectly smooth, but  
with the command above it is a bit choppy. I was advised to use "-channels  
6" to prevent load as the CPU converts 6 channels to stereo, but when I  
use this command MPlayer says:

"failed to set audio device to 6 channels
Could not open/initialise audio device -> no sound"

What I would ideally like is to be able to some how dump the other  
channels and just play 2 channels. My sound card is a Creative Sound  
Blaster Live!

I also tried doing "-af channels=6" but that hasn't worked either. Any  
advice for smoother playback would be highly valued. Thanks.