[mythtv-users] Not getting Dolby Prologic out of s/pdif

[Marco Nelissen]

>Hi all,
>
>I know there's been loads of posts on s/pdif & 5.1 topics, but I've been 
>bashing my head against this for quite a while and still am stuck :-(  
>
>I'm using the s/pdif output on my VIA 82xx sound card with success when 
>playing DVDs in myth-dvd, all my speakers produce sound and everything is 
>hunkydory.  
>
>However, when watching live tv I'm only getting the front L & R speaker 
>producing (not very good) sound.  I was expecting all the speakers to emit 
>sound in a dolby prologic stylee, or am I mad?  
>
>I have AC3 pass through set in both my Xine config and mythtv settings.  

Dolby Prologic is not the same as AC3. Prologic is 4 channels encoded into
an (analog) stereo signal. AC3 is 5.1 discrete digital channels. Are you
capturing a digital signal that has AC3 audio, or are you capturing using
an analog capture card? If the latter, you're not going to get AC3/5.1, and
the best you could do is to force your receiver/amplifier into prologic
mode rather than plain stereo mode.