[mythtv-users] Simultaneous AC3/DTS passthrough & stereo analog output

[Bob]

I'm using an Audigy2 in one PC and an SB Live value in another (both 
Debian etch) and I output to a 5.1 speaker system over S/PDIF coax and 
to my headphones (via the TV) over analogue stereo.

I have AC3 passthrough working when I call mplayer with -afm hwac3, (I 
think DTS will work but can't find a test clip) and I can soft decode 
and downmix the AC3 audio with -afm liba52, so that's all great, except 
that with -afm liba52 rear left and right are mixed and I don't get 
anything out of the LFE track.

What I can't do is both at once which would make life easer for SWMBO.

My google search (below) has reviled I'm not alone in wanting this 
(including a number of threads here) but hints that it may not be 
possible, however, my search skills are week so I thought I'd ask.
"ac3 passthrough" "analog (output | stereo | downmix)" (simultaneous | 
"both at" | "same time")

Has anyone got any suggestions on how to get this working?

I can install more than one sound card, so if it can be done but only on 
a second card I'm still interested in the solution

Thanks for any help.

PS: Though the PCs in question aren't MythTV frontends at the moment, 
that is their destiny and since this community seems to be one of the 
most knowledgeable with regard to linux sound issues I thought I'd ask here.

PPS: I asked the same question on the debian-user list 10 days ago but 
with no luck so sorry to those who, like me, are subscribed to both.