Forgive me if this is posted somewhere else. I have been searching for a solution for quite some time and hadn't found this exact solution, so I thought I'd post it here for anyone else in my situation.

First of all, my particular Motherboard:
MSI PM8M-V Socket 478 - Onboard VIA8237

Checked for what audio I had
Purchased the RCA JACK AND SPDIF BRACKET and connected it to my motherboard (had to reverse wire pin-out, no big deal)

I had digital out with Windows, so I knew it worked. I tried following the directions on http://www.knoppmythwiki.org/index.php? ... AudioHowTo and that got me half-way. I turned off "AC3 Passthrough" and "Use Mythtv volume controls" and chose /dev/adsp. Still no output.

I then came across this article: http://forums.gentoo.org/viewtopic-t-48 ... ight-.html
I followed these directions and now have digital-out working perfectly!!



I hope this helps someone else!

Knoppmyth rocks!

I to was having the same problem, My sound chipset is via 8237, when I connect the spidf header from my HTPC case, and change the audio to use AC3 passthrough, and set the device to /dev/adsp, all I get is a cracking almost static-like noise. I will first try to reverse the wiring, and then I will attempt this fix.

Thanks for the post, I can't wait to see what happens.


I will post my findings later this evening.

I tried the steps in this post, and everything worked perfectly. But now my sound when switching to /dev/adsp, and enabling AC3 passthrough, gets me a most unagreeable Static like sound. Could I maybe have the wiring reversed. I remeber the header on my HTPC case only had 2 wires, could they be reversed?

I'll try that if you think it will help.

Regards.

Honestly I'm not sure. I noticed when I first tried firing up my machine after hooking up the bracket, I was unable to even boot them machine. I reversed the wires and it turned on. I loaded up an instance of Windows, popped in a DVD and verified that it worked (via SPDIF passthrough)

You might try reversing them. If it still doesn't work, let me know and I'll check out how mine is wired.

Good luck!

BTW, So far the only show I've seen in 5.1 is the PGA Championship this past Saturday. Everything else has been in 2.0. And come to think of it, my DVD's don't play in 5.1 either... I'm using XINE. Strange?

However...It is using the SPDIF regardless, so it's a start!

[EDIT] Try DIS-abling AC3 and DTS passthrough. See if that helps

Last night I went home, and powered down mythbox, and checked the wiring on the SPIDF header on the nmediapc HTPC case (model 200B). It was in fact wired incorrectly. The header pinout, is improperly labeled in the manual, it is laid out thusly:
[o][o][ ] > pin 1 is SPIDF pin 2 is GROUND
On my mobo the header pins are this way:
[o][o][ ][o] > pin 1 SPIDF pin 2 +5V pin 3 not used pin 4 GROUND.

As the header on the case was a 3 pin type, I went and retrieved an old cdrom audio cable, and transferred the pins to it this way:
[o][ ][ ][o] > pin 1 SPIDF pin 4 GROUND.
Now when I switch my receivers audio inputs to Auto it selects digital. However I have no sound. When switching back to analog manually, I get like a staticy clicking with "Enable AC3 passthrough" So the receiver is sensing a digital signal from the mythbox, but I have no sound. I wonder if you could share your "Utilities-Settings" > "Setup" > "General" audio settings, i.e /dev/dsp, /dev/adsp, etc.

Thanks again.

Using R5C7, my settings are this:

Audio output device: /dev/adsp
(not checked) Enable AC3 to SPDIF passthrough
(not checked) Enable DTS to SPDIF passthrough
(not checked) Agressive Sound card Buffering
(not checked) Use internal volume controls

-also-
Important to note, when I run
pvr # alsamixer

I had to make sure that the IEC958 was selected to PCM and that IEC958 Playback was 0. (That's what the inital command line setting did) Or else I had no sound.

Hope that helps!

BTW, are you using coax or optical out?

I will check the settings. I'm sure they are at /dev/dsp. I am using the coaxile (rca) type connection.

I am not sure of the alsaconfig settings, although I beleive last night I had the IEC958 all the way up.

I'll try this tonight.

Thanks

ok, i now have digital output for all mythtv sound. keeping the setting in alsamixer for IEC958 to "0" is the answer. If I try to increase it above "0" the sound goes away. Still no luck with AC3 anything, incluidng Xine. But for now at least all of my sound is digital.

Thanks, I'll keep,working on it.

Glad to hear that worked! Now you're in the same boat as me. If you figure anything out with XINE and AC3, let me know (and vice versa.)

sjerome,
I was browsing google for the Realtek ALC655 and came across this posting. About halfway down the page it mentions the same situation we're facing. He muted the IEC958 channel and it worked, but it's still all in stereo. Maybe there's something someone can glean from this to help us out!

http://forums.whirlpool.net.au/forum-re ... m?t=461197

Good luck

ok in reviewing the link from the last post, and doing some playing around with the alsamixer settings, I have Dolby digital working. It is only a slight modification from your first post.



So now in looking through all the posts and pages, I found one common denominator. hw:0,2 the device known as 0,2 is the default for so many different digital audio devices, I figured why not try it out. After setting the IEC958 device to 2, changing the setup back to /dev/dsp, enabling AC3 and DTS passthrough, and then using alsamixer, setting the IEC958 volume to "0" and insuring its using PCM, now my HDTV is doing Dolby Digital, also by changing the audio settings in xine from "Stereo 2.0" to "Passthrough" my DVD's now playback in 5.1 DolbyDigital as well. By default you do not have the option in xine to modify the audio settings, to enable this option, from the "gui" tab, change "Configuration Experience Level" to "Master of the known universe" and then the audio tab, and video if you are using XvMC, can now be fully tweaked.

This is where I am at for now. Let me know how you make out.

Best Wishes

_________________
Knoppmyth R5D1 - Mythtv .20svn-fixes
HD Frontend/Master Backend
AMD64 3200+-1GB Corsair-800GB LVM PATA/SATA
Biostar GeForce 6100 Motherboard M109
1x Air2Pc rev.2 1x PVR150MCE
Maddog DVD/RW-DL Drive

Sorry for the delay in responding. I've been a bit sidetracked lately. I just had a chance to check the settings you mentioned.

As soon as I set:

and check those settings I see this:
NOTE - Mono: 2 [67%] whereas yours says Mono: 2 [0%]

I checked with alsamixer and muted the IEC958, but this changed it to Mono: 0 [0%]

How did you change that setting? And where did you change the xine settings? (Couldn't find a 'gui' tab)

To set the output to 67%, I used the IEC958 column in alsamixer, it is right beside the 2 IEC958 columns that need unmuted

As to the xine setup, open xine in an xterm. Right click and click the "show GUI" box. This should open the gui up. After it is up, click the settings button, I beleive in the default skin it is the lower left button, all the way on the bottom of the gui, lower most icon (looks like wrenches). The very first tab that shows up, is the "gui" tab. There you should see the drop down box that says "Beginner" change it to "Master of the known universe" then click the audio tab, look for the box that says "stereo" or "2.0" the very last option is "passthrough" That is the ticket.

Let me know how you make out.

_________________
Knoppmyth R5D1 - Mythtv .20svn-fixes
HD Frontend/Master Backend
AMD64 3200+-1GB Corsair-800GB LVM PATA/SATA
Biostar GeForce 6100 Motherboard M109
1x Air2Pc rev.2 1x PVR150MCE
Maddog DVD/RW-DL Drive

Ok, in alsamixer I see three IEC958 columns. Here's what they look like:




I can change the first column to either PCM, Analog I or IEC958 I
I cannot change the 2nd column at all
I can change the 3rd column to either 0, 33, 76 or 100%

As soon as I unmute column 3, I have no more sound...

Thanks for the help!