[mythtv-users] Where to get a S/PDIF adapter?

Rod Smith mythtv at rodsbooks.com
Fri Feb 2 21:16:03 UTC 2007

On Friday 02 February 2007 14:33, Rich West wrote:
> >>> 
> >>>
> >>> It is a three pin S/PDIF connector where the individual pins can be
> >>> re-arranged to match your motherboard configuration.
> Got the adapter yesterday and started tinkering with it today.  It was
> very easy to re-arrange the pins to match the orientation on my
> motherboard.  Unfortunately, with the Shuttle SK21G, the socket didn't 
> quite match the connector on the SPDIF cable.
> I was able to get 5.1 surround sound out of it almost right away (over
> the optical) via mplayer (no .asoundrc file needed).  I can't seem to
> get MythTV to talk to it at all (either via playing the same DVD video,
> watching a recording, watching live tv, or playing music).  I followed a
> couple of how-to's (I'm running FC5) and a bunch of postings on the list
> in an effort to direct all audio out via the SPDIF adapter, but I
> couldn't get anywhere with it. :(

I see that the Shuttle SK21G uses a VIA chipset. My Biostar PT880 Pro-A7C 
motherboard also uses a VIA chipset, although not exactly the same one. (I've 
got a VIA PT880 PRO/VT8237R chipset for Intel 775, yours has a VIA K8M800CE 
chipset for AMD socket 754. I'm assuming yours uses some variant of the 
VT8237 for sound generation.) When I first tried the bracket with the 2.6.17 
kernel that came with my Ubuntu 6.10 release, I got 5.1 audio out of mplayer 
but only 2-channel audio out of MythTV, even when playing the same DVDs that 
produced 5.1-channel output with mplayer. After upgrading to a 
locally-compiled kernel (using "generic" source code from 
http://www.kernel.org), 5.1 output began working with MythTV. I did need to 
futz with some ALSA mixer settings, though. Here are my /etc/asound.conf 
and /var/lib/alsa/asound.state files:


I don't know for certain that the stuff in the asound.conf file is absolutely 
necessary; I just stopped futzing once everything worked. Also, asound.state 
is found in /etc on some systems. These files may not work exactly as-is for 
you, but they might provide some useful clues. I recommend going through my 
asound.state file section-by-section, comparing it to what you've got, and 
making adjustments based on your local configuration. Back up your own files 
first, of course.

Best of luck getting 5.1 output working. As a worst-case scenario, having the 
bracket might enable you to buy a slightly cheaper sound card with an SPDIF 
header but nt optical output connector compared to buying one with the 
optical output connector.

Rod Smith

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