ATI 5850: Game audio over HDMI?

[AndyKH]

Hi

I've been reading up on ATI 5850 graphics cards, but I can't figure out exactly how the audio over HDMI functionality works.
Before I continue, I should mention that I don't care much for the HD audio bitstreaming capabilities when watching Bluray movies - I have a dedicated BD player for that. Rather I'm interested to know how it handles outputting multi channel audio from games over HDMI when I occasionally move the computer from the office to the living room for some big screen gaming. It should also be noted that I plan to get the cheapest Auzentech X-fi card I can find for playing EAX games (through alchemy on Win7) or OpenAL games.

It is my impression that the 5850 actually functions like a seperate audio card with much the same capabilities as onboard sound on motherboards, and that I will have to select the ATI audio device whenever I want to use it.
However, how does this leave me when playing games EAX or OpenAL games? Is it somehow possible to transfer the processed multichannel sound from the X-fi card to the 5850 card, or will I simply loose hardware 3D sound when using the HDMI audio ouput?

Btw, I'm aware of the Auzentech Theater HD (IIRC) card that can add audio to a HDMI signal, but I find it rather expensive.

 

[postmortemIA]

Auzentech X-fi card have optical out,. that way you preserve positional audio.

I've ran ATi 4870 audio pass-through to HDMI TV set which then goes to receiver, and it works fine. Most today games don't use EAX, they use some custom software implementation that runs fine on onboard sound cards.

 

[Zap]

It has onboard audio so you will not be getting sound from your Auzentech.

 

[nenforcer]

I'm under the impression that it just passes through audio over the HDMI link and does not do any audio processing of its own.

I can see this working when playing a Bluray it just passes the audio to a TV or to a receiver which then does the Dolby Digital or DTS processing at the other end.

I'm not sure how it would work for something that is using either DirectSound / DirectSound3D or OpenAL (which just translates into UAA or DirectSound calls?). Does this imply you must have a sound card (either onboard or discrete) to process these commands but it could get altered going over HDMI?

I don't believe either Geforce or Radeon video cards implement the software stack like a true hardware accelerated sound card, they just pass the data over HDMI.

 

[Pooptacular]

I run HDMI from my 5850 to my receiver specifically for 5.1 sound. It works great. As far as I'm aware the 5850 just passes through the sound to my receiver. My receiver shows that it is receiving 5.1 PCM. I don't know about EAX support nor really care. I get 5.1 PCM on all of my pc games and thats what matters.

I asked about this before I purchased my 5850 and it seems no one posts about this stuff, I had to buy it to find out if it would even work fine, I am not sure why but whatever, it works.

Also, if your running HDMI out from a Playstation 3 to your receiver, it works exactly the same way. My receiver shows 5.1 PCM.

 

[Bipedal Humanoid]

No it doesn't merely pass through the audio, at least not from the soundcard. Using audio via HDMI renders my soundcard useless (ie, no equalizer control, no EAX-like features, no Dolby ProLogic etc)

You can use either your soundcard OR the 5850's onboard audio chip.

I'm still trying to find more detail and specs on ATI's soundchip. For example, whether it carries Dolby Digital/ DTS signal and what the bit rate is (likely 16bit).

EDIT:

From the 5850 specs:

Integrated HD audio controller

Output protected high bit rate 7.1 channel surround sound over HDMI with no additional cables required
Supports AC-3, AAC, Dolby TrueHD and DTS Master Audio formats

 

[lamedude]

It can carry 192KHZ 24bit PCM if you have any DVD-Audio to listen too. Right click volume in taskbar,playback devices,right click AMD HDMI Output,properties,advanced.