Dolby Digital - am I right in thinking

[lovedaddy]

Was thinking about upgrading to a whole new system. Was wanting a soundcard that can produce true DD5.1 streams. (Ut2003 and Doom3 I think are going to support this).

Have been looking about the net, and whilst the SBLives! and various onboard soundcards seem to be able to output 5.1 streams (say in a pre-rendered sequence), they are only capable of producing 4 channel audio on the fly (basically DirectSound3D).

Am I right in thinking that only the nForce is able to produce on the fly, real time encoded 5.1 audio streams to output to a digital decoder?

Thanks in advance.

 

[Embattle]

I know my Audigy outputs, via optical out, to my DigiTheatre decoder box. As long as the Decoder box recognises a DD5.1 stream it automatically switches to AC3.

 

[lovedaddy]

Aye, I was almost positive that the Lives etc can output a pre-coded stream, but I'm still wondering, are they able to encode a stream (say relating to whats going off in game).

 

[Embattle]

The Digital out that's fixed at 48 kHz can be used for stereo, 2-speaker 3D sound, Live!Surround (like Dolby Prologic but for all games using 3D sound) and AC-3 pass-thru. Creative's official answer is it cannot be used for DTS pass-thru with current drivers but it works just fine which makes sense since its just passing a digital stream. We think its simply a matter that until something has been testing and tested by Creative, "not supported" is a way of avoiding having to answer questions on this feature.

More here:

http://www.3dsoundsurge.com/reviews/Live/Live-p9.html

Games might be different.

 

[Embattle]

I guess as long as UT2003 has the option to select SPDIF I'll be fine

 

[lovedaddy]

Mmmm, not too convinced. The DVD's have the streams incoded into the regular 2-channel stream. The SBlive aint coding anything there. If you play halo on the xbox, things like the shells that fire from your gun are sourced in realtime in 5.1 (and its amazing).

 

[Embattle]

There seems to be three parts to decoding DD....Drivers, Hardware and software and tbh I wasn't impressed with the decoding ability of the Audigy although now I just have it pass thru to the Digi box which does a good job.

 

[lovedaddy]

http://www.msicomputer.com/msiforms/k7n2.asp

"For digital music enthusiasts the NVIDIA SoundStorm audio solution also incorporates the industry’s only real-time Dolby® Digital encoder that can take any 2D or 3D audio source and output it digitally, through a single cable, to your home theater system"

 

[Embattle]

I would have my doubts about it achieving accurate DD.

 

[lovedaddy]

It's dolby digital certified, they generally dont give that out unless its upto scratch.

 

[Embattle]

Originally posted by lovedaddy
It's dolby digital certified, they generally dont give that out unless its upto scratch.

True but it's still no guarantee it will work properly with every 2D or 3D audio source.