[mythtv-users] ALSA and real AC3 passthrough

Chad masterclc at gmail.com
Fri Dec 30 20:53:57 EST 2005

> How would your reciever understand a mix of AC3 and PCM data at the same
> time?  Or were you using two seperate outputs (ie: digital for AC3 and
> analog for MP3/etc)?
> Jeff.

My receiver detects whether it's digital or analog and 'switches'
accordingly from the same input.  My test is from DVD's and AVI's, as
well as from xbox games.  I have my DVD player hooked up to my
receiver via optical, and if a movie is AC3 (Dolby Digital) the
receiver 'clicks' and shows a light that says "Dolby Digital". 
Otherwise, it just outputs with whatever fancy arrangement I pick (all
stereo which outputs the same audio to the L/R to the Rear L/R, or a
surround that is created by the receiver).  Same with Xbox games that
support DD/AC3 audio.

I'm not so lucky however.  I cannot, for the life of me, get any of my
soundcards actually working with their SPDIF ports (digital coax). 
I've tried nearly every setting in alsamixer and dorked with my
/etc/asound.state file, tried different options with ~/.asoundrc but
get nothing, no PCM or AC3.

Just figured I'd clarify how some people probably expect this to work.


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