I have tried to get AC3 passthrough working on multiple motherboards using s/pdif and I have been unsuccessful. I decided to try again on my ASUS M2NPV-VM because I am now recording and watching HD shows and I wanted to get some better sound out. I follow the instructions on knoppmythwiki.org and I just can't get the system to work.

Here's my symptoms:
When I watch SD recordings or live TV everything works fine, and my receiver displays "PCM 48". When I try and watch a DVD in Xine, or a recorded HD program, my receiver displays "DEC EROR" and I don't get any sound.

This is the same problem I've had over multiple versions of Knoppmyth and multiple motherboards. I'm currently trying this with R5D1 and ALSA 1.0.13rc3. My receiver plays surround sound just fine when using s/pdif out of my DVD player. The receiver is a Sony.

Any suggestions on what my problem may be? I'm guessing it's the receiver, but I don't understand why it can play a DVD from my DVD player fine, but not an .iso from my frontend.

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LinHES 8.3, 1 BE, 3 FE

I assume you have purchased and installed the SPDIF add-on card for your ASUS M2NPV-VM motherboard as I believe this is the only way to get digital audio output working. If this is NOT the case then please let us know what your exact setup is.

Have you tried running 'alsamixer' at the command line and making sure your digital output is unmuted?

It sounds like you are using Xine to play DVD's, have you gone into the audio setup menu and set it to 'passthrough'?

Please post what you have set in myth setup for you audio output. I believe the standard is /dev/dsp but that doesn't always work for everyone.

The more information you provide about your setup and what you have already tried the better advice we can give.

Also, have a look through the Digital Audio wiki page:

http://knoppmythwiki.org/index.php?page ... AudioHowTo

Martian

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ABIT NF-M2 nView | Athlon 64 X2 3800+ | 2GB DDR2 800 | HDHomerun | GeForce 6150 (onboard) | WD 640 GB SATA HD | DVD-RW (sata) | StreamZap IR receiver with Logitech Harmony remote

Vizio 37" LCD HDTV (1080p)

Thanks for replying, and I'll try and be clear in my responses.


YES, you are correct.


YES, if I don't do this, I don't get any audio. The fact that I'm getting the "PCM 48" audio when the only cable I have connected the the s/pdif cable tells me that I'm correctly getting sound out of my digital connection.


YES, I did this as well.


/dev/adsp (again, until I do this I do not get any sound out, regardless of HD or not).


That's where I got all my info to set this up from...

To me, it almost seems like the format that the AC3 audio is in is imperceptible to my receiver...

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LinHES 8.3, 1 BE, 3 FE

I think your problem is with /dev/adsp.

I would try changing it to something like ALSA:spdif or ALSA:digital or ALSA:hw:0,0 or maybe ALSA:hw:0,2. Sometimes you can even get away with simply ALSA:default but I think that causes problems with analog tracks.

Perhaps this link will can provide a little bit more insight than my ramblings:

http://www.mythtv.org/wiki/index.php/Co ... ital_Sound

Best of Luck!

Martian

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ABIT NF-M2 nView | Athlon 64 X2 3800+ | 2GB DDR2 800 | HDHomerun | GeForce 6150 (onboard) | WD 640 GB SATA HD | DVD-RW (sata) | StreamZap IR receiver with Logitech Harmony remote

Vizio 37" LCD HDTV (1080p)

post how you fixed this if you have a chance

For me xine worked when I've put mono, strereo and surround 40 and 51: ALSA:plughw:0,2 and passthrough .

My receiver displays Dolby EX for Dolby Digital 5.1 or ES.MTRx6.1 for DTS sources.

mplayer says it uses only 2 channels for output, even if I use -channels 6, same happens with xine.

Does anybody know how to get true DD5.1 or DTS5.1 from sound card?