SPDIF in, 5.1 out - setup questions

[marenka]

I would like to use my computer to manage the 5.1 sound coming out of my DVD player. Here's my setup:

DVD player with coaxial SPDIF output
Computer with M-Audio 24/96 card that has coaxial SPDIF in and an Audigy 2 card with analog 5.1 out.

I would like to have the AC3 output of my DVD player to go through the M-Audio card via SPDIF, then be decoded and output through the Audigy 2 5.1 analog outputs so I can listen on my 5.1 computer speaker setup. I don't want to just play the movies from the computer DVD drive, because the computer is in a different room and I want to use the DVD player's remote control. And I don't want to get an additional AV receiver and another set of speakers.

Is there a way to have my computer function as an AC3 decoder with the hardware I have?

[edDV]

I would like to use my computer to manage the 5.1 sound coming out of my DVD player. Here's my setup:

DVD player with coaxial SPDIF output
Computer with M-Audio 24/96 card that has coaxial SPDIF in and an Audigy 2 card with analog 5.1 out.

I would like to have the AC3 output of my DVD player to go through the M-Audio card via SPDIF, then be decoded and output through the Audigy 2 5.1 analog outputs so I can listen on my 5.1 computer speaker setup. I don't want to just play the movies from the computer DVD drive, because the computer is in a different room and I want to use the DVD player's remote control. And I don't want to get an additional AV receiver and another set of speakers.

Is there a way to have my computer function as an AC3 decoder with the hardware I have?

I assume you have asked Creative for support. Hard to answer without putting same hardware in a machine. It seems if your speaker system has a AC3 decoder then you are set to go. If the speaker system doesn't have a AC3 decoder where do you have one?

[greymalkin]

audigy 2 decodes AC3 5.1 and DVD-Audio

[guns1inger]

The issue appears to be how to route the spdif input through to the audiology card. I would look at the drivers settings for the m-audio card. There is a tab specific to spdif, and the card does support pass through for both AC3 and DTS input via this channel. I have gleaned this just from m-audio's website. How it works in practice is up to you to discover.

[marenka]

I've figured out how to set up the M-Audio card to pass through the AC3. And the Augdigy 2 card will decode 5.1 sound from a DVD (or else PowerDVD is doing the decoding). I can play a Divx file with 5.1 AC3 audio, but the audio track has to pass through AC3Filter to be decoded. My speakers do not decode 5.1 themselves.

I wonder if what I need is a full featured audio editing program which will allow me to set input and output streams. The driver settings for the 2 cards don't seem to come together well enough to link the output of one to the input of the other. I was wondering if the correct set of filters set up in GraphEdit would do the trick. When I tried to do that using the M-Audio card from the "Audio Capture Sources" filter list, then AC3Filter from "DirectShow Filters" then SB Audigy from the "Audio Renderers" filters, linking the output to input pins gives the message "These filters cannot agree on a connection". I can link the Capture (output) pin of M-Audio SPDIF to the Audigy input pin directly, but I just get digital noise out of the speakers.

[edDV]

I've figured out how to set up the M-Audio card to pass through the AC3. And the Augdigy 2 card will decode 5.1 sound from a DVD (or else PowerDVD is doing the decoding). I can play a Divx file with 5.1 AC3 audio, but the audio track has to pass through AC3Filter to be decoded. My speakers do not decode 5.1 themselves.

I wonder if what I need is a full featured audio editing program which will allow me to set input and output streams. The driver settings for the 2 cards don't seem to come together well enough to link the output of one to the input of the other. I was wondering if the correct set of filters set up in GraphEdit would do the trick. When I tried to do that using the M-Audio card from the "Audio Capture Sources" filter list, then AC3Filter from "DirectShow Filters" then SB Audigy from the "Audio Renderers" filters, linking the output to input pins gives the message "These filters cannot agree on a connection". I can link the Capture (output) pin of M-Audio SPDIF to the Audigy input pin directly, but I just get digital noise out of the speakers.

Like guns1inger said, it's a signal routing issue to connect the M-Audio SPDIF input to the Audigy 2 hardware AC-3 decoder. Best people to ask would be upper level Creative CSR's or find an Audigy 2 experts forum.

[marenka]

I made some progress. I needed to change the Audio Setup on my DVD player. I changed the Digital Output setting from "All" to "PCM Only", and now the GraphEdit patch from M-Audio SPDIF capture to SB Audigy renderer does give me the correct audio signal. The only problem is that there is a significant (nearly a second) delay in the audio stream before the Audigy card plays it.

[edDV]

I made some progress. I needed to change the Audio Setup on my DVD player. I changed the Digital Output setting from "All" to "PCM Only", and now the GraphEdit patch from M-Audio SPDIF capture to SB Audigy renderer does give me the correct audio signal. The only problem is that there is a significant (nearly a second) delay in the audio stream before the Audigy card plays it.

I bet the PCM is only 2 Channels as well. I think you are up against AC-3 input lockouts to prevent it from being used as a generalized AC-3 decoder.

Best to ask an Audigy expert.

[marenka]

Thanks, I'll see if I can find a solution from an Audigy expert. You're right that the PCM input is only 2 channels. I read the box of my M-Audio card a bit more carefully. It supports surround-encoded AC-3 and DTS pass-through, but Windows XP required for Dolby Digital and DTS "pass-through" and I am using Windows 2000.

Even if I can't get this particular setup to work, I'm interested if others have been successful using audio cards for doing their multichannel sound decoding from an external source using SPDIF in.

[guns1inger]

Given the routing you are going to have to do, I suspect that the delay is something you may not resolve. Good luck though.