2900XT AUDIO question

G

goud

Limp Gawd
Joined
Apr 18, 2005
Messages
220
Yes, audio question.
In the facts sheet on the 2900 I keep seeing audio support, I am fuzzy on what this means;
What I think I know is that the HDMI output on the 2900 will include audio content.

Questions;
Does this mean a HDMI output from a 8800 card does not do this?
Also how does the 2900 get that audio content?
1.some sort of connection to your audio subsystem or...
2. direct digital audio decode on the video card


Thanks
 
There isn't a connection.

I think it more or less captures the output from the audio mixer using software similar to what Total Recorder does.
 
The 2900 cards HDMI sound thing is indeed bit fussy, but there should indeed be a sound "controller" integrated to the R600 core.

Answers to your guestions:

No G8* card can do HDMI sound as 2900 and upcoming low/middle range ATI cards do, this is unique to ATI cards. HDMI sound may be possible with other cards by method in lower picture, but needs hardware support and external cabling.

Previous HDMI method

How R600 handles the HDMI I cannot explain in detail as my knowledge hits the wall. Hopefully these pictures help abit:

2900 HDMI audio controller

2900 audio driver

So to my understanding, the sound is produced on R600 cards sound controller which is integrated to the GPU. I might very well be wrong and happy to be corrected. This is how I have understanded the thing from couple reviews.
 
Great post response thanks
Now I am confused on my video card choice, thought I was going GTX but this audio thing seems important.....
 
goud said:
Great post response thanks
Now I am confused on my video card choice, thought I was going GTX but this audio thing seems important.....
Click to expand...

Well the R600 audio is only important if you definetly want to use one cable as in HDMI. You can always use 8800 card to output video signal via DVI and 5.1 sound via S/PDIF. This archieves (8800 & S/PDIF) the same result with two cables as R600 does with single HDMI cable.

ATI has toutted alot that their system is totally compatible with Vista and upcoming HD video standards if that matters anything.

edit:

I must add a question, what kind of a system are you planning to build? Gaming or HTPC machine or a little bit of both?
 
The 2900HD (as I already stated in the other thread of yours, just trying to make sure the point is made) does not approach 8800 GTX performance levels, particularly if you want to run mid to high levels of AA and AF. It bogs down terribly in some applications.

Yes, you will need a second cable for the 8800GTX, as it will not support sound via HDMI, but you will get the same sound quality, so there is no real loss there.
 
Unfortunately so. HDMI 1.0 and above support up to eight channels of PCM at up to 24-bit/192kHz, but AMD decided that they did not wish to support this. Even S/PDIF, a much older consumer-grade digital audio interface, supports up to two channels up to 24-bit/48kHz, and most every motherboard codec supports S/PDIF output via TOSLINK.

One problem with many receivers (if not all), however, is that you will not be able to pull a video feed from the HDMI input and pull audio from the S/PDIF input. So, in some cases, this combined video+audio stream will be a requirement for usable HDMI input.

There are other products on the horizon that will input a DVI signal and output multichannel audio up to 24/192kHz via HDMI (with full EAX 5.0 and so on), but this actually has not been officially announced, nor will it be inexpensive.
 
phide said:
Unfortunately so. HDMI 1.0 and above support up to eight channels of PCM at up to 24-bit/192kHz, but AMD decided that they did not wish to support this.
Click to expand...
Well, I guess this leaves the door wide open for someone else to implement it.
Even S/PDIF, a much older consumer-grade digital audio interface, supports up to two channels up to 24-bit/48kHz, and most every motherboard codec supports S/PDIF output via TOSLINK.
Click to expand...
Actually SPDIF can do 24bit/96kHz.
One problem with many receivers (if not all), however, is that you will not be able to pull a video feed from the HDMI input and pull audio from the S/PDIF input. So, in some cases, this combined video+audio stream will be a requirement for usable HDMI input.
Click to expand...
What? I'm not aware of a single receiver that has a HDMI input that can't use the video from the HDMI input and audio from an SPDIF input. My Pioneer Elite 84TXSi can do this. In fact I'm doing it right now as I'm watching a HD-DVD.
 
Stereodude said:
Actually SPDIF can do 24bit/96kHz.
Click to expand...
My belief is that 96 kHz is not outlined in IEC 61937, which makes it non-standard. There is no way to declare 96 kHz as the sampling rate with the channel status bits, as only AES/EBU allows the sampling rate to be undefined. As to whether S/PDIF "supports" 96 kHz is iffy. Leaving some of the CS bits open is something of a tricky proposition, in my opinion.

Stereodude said:
My Pioneer Elite 84TXSi can do this. In fact I'm doing it right now as I'm watching a HD-DVD.
Click to expand...
Then I stand corrected. I've been told a number of times that many receivers do not support this, though it's possibly related to HDCP limitations. If R600 (or whatever chip is handling this work) is spitting HDCP-protected content full-time, this might not work, and I guess understandably so.
 
Great information here, thank you. I think for me, bottom line is I don't see needing HDMI(with audio) support so I think I will go GTX however the performance results I have seen do NOT show the GTX to be greatly superior 10-15% performance gain tops but I am running 1900x1200 so I think that might make a difference.

One thing I think I have learned is that should you want to use HDMI you will have to have a reciever to make the 8800 work, this is a big additional expense and I think makes the 2900 a MUCH better HTPC choice, IMHO
On second thought if Iam doing HTPC I would probably have a reciever in the mix anyway.....so this might not be such a big advantage? I think I have just figured out the final piece of my equation, audio on HDMI is really a not needed feature(for a PC), 8800GTX here I come.....
 
phide said:
My belief is that 96 kHz is not outlined in IEC 61937, which makes it non-standard. There is no way to declare 96 kHz as the sampling rate with the channel status bits, as only AES/EBU allows the sampling rate to be undefined. As to whether S/PDIF "supports" 96 kHz is iffy. Leaving some of the CS bits open is something of a tricky proposition, in my opinion.
Click to expand...
Well, either way I've got a DSP that outputs 24/96 via SPDIF and every receiver I've had will accept it. :eek:
 
goud said:
On second thought if Iam doing HTPC I would probably have a reciever in the mix anyway.....so this might not be such a big advantage?
Click to expand...
Bingo - though a receiver is not really necessary with PC speaker sets.

HDMI is great for digital transport, but not the way AMD implemented it. Then again, it's HDCP-compliant, so that will end up being a big deal at some point. If you want to play HDCP-protected content in Vista, and output digitally, that capability is necessary, or at least I'm pretty damn sure it is.

Stereodude said:
Well, either way I've got a DSP that outputs 24/96 via SPDIF and every receiver I've had will accept it. :eek:
Click to expand...
Many will ignore the relevant header bits and operate in a native 96 kHz mode, while others may skip bits, downsample (not sure how prevalent this is) or simply won't work at all. Ignoring the channel status bits doesn't flag a device as non-compliant per se, but not all devices will play along.

The divide between AES/EBU and S/PDIF never should have happened, but with Sony being a big part of the picture, most aren't afraid to skirt around the standards a bit to get things to work as they should.
 
goud said:
Great information here, thank you. I think for me, bottom line is I don't see needing HDMI(with audio) support so I think I will go GTX however the performance results I have seen do NOT show the GTX to be greatly superior 10-15% performance gain tops but I am running 1900x1200 so I think that might make a difference.

One thing I think I have learned is that should you want to use HDMI you will have to have a reciever to make the 8800 work, this is a big additional expense and I think makes the 2900 a MUCH better HTPC choice, IMHO
On second thought if Iam doing HTPC I would probably have a reciever in the mix anyway.....so this might not be such a big advantage? I think I have just figured out the final piece of my equation, audio on HDMI is really a not needed feature(for a PC), 8800GTX here I come.....
Click to expand...

The GTX may not beat out the 2900HD by a huge margin in all things... but the things it does beat it out in (particularly with AA and AF at mid to high levels) it wins by a mile. Neverwinter Nights 2 comes to mind.
 
No G8* card can do HDMI sound as 2900 and upcoming low/middle range ATI cards do, this is unique to ATI cards. HDMI sound may be possible with other cards by method in lower picture, but needs hardware support and external cabling.
Click to expand...

At work and at trade shows I have seen 8600 cards with on-board HDMI (no DVI adapter as used by ATI) and it does indeed output audio as one would expect.
 
Lomic said:
At work and at trade shows I have seen 8600 cards with on-board HDMI (no DVI adapter as used by ATI) and it does indeed output audio as one would expect.
Click to expand...

Ok stand corrected there, did read 8600 reviews without too much consentration :)

One guestion, did it need somekinda cabling between the card and the audio card/codec/controller as the picture suggestes here:

External spdif cabling?
 
I have a 7 year old Sony 5.1 digi/analogue amp that supports 96KHz digital.
I used it for a long time at 96KHz with a Sound Storm chipset and it worked fine.
Only downside being the Amps onboard computer isnt fast enough to do a lot of the DSP functions so its almost like a straight through 5.1 analogue connection.

So the spec for 96KHz was developed enough at Sony to work well 7 years ago.
I cant vouch for other mfrs.

fyi :)
 
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