[mythtv-users] PCM sound card output and volume control question

[Carl Alexander]

I have a setup in which I run digital cables from my Myth box to my AV 
receiver, and it is there where I do my D/A conversion and volume 
control.  My question is, in such a situation how is the linux/Myth 
mixer actually controlling the volume? (Which I guess is the same as 
asking "how is volume regulated on a TOS-link PCM connection?")  If I am 
playing a ripped CD, is the mixer actually molesting the 16-bit samples 
form the raw CD data before sending them out?

What I am getting at is I would like for my digital audio files to be 
passed to my AV receiver and Amp untouched.  I'm quite happy with this 
equipment and don't need a mis-set mixer monkeying around with the 
signal in a way that could impact its dynamic range.  Is there a way I 
can tell myth to completely ignore all mixer settings?  There is no 
level settings on the digital output of my CD player, why here?  I want 
to play my audio, not have a drive-by remastering done to it on the way out.

I am immediately concerned with MythMusic since I am playing with that 
first, but I can see wanting to extend this to DVD playback, HDTV 
playback, etc.

Yes, I see the toggle for pass through of AC-3 audio (which I have set 
but haven't really used since I haven't played with MythDVD yet).  if 
that does what I think it does, I pretty much want that for other 
digital sources as well.


    Thanks.

    --- Carl