HD Decoding Confusion

[StephenP]

Hi,

I'm planning on building a fairly simple htpc and am having a hard time figuring out if the Ati 2400 and 2600 family of cards are equally good at the decoding. I want an ati card because it does the audio decoding for the hdmi on board which means it can output the new hd audio formats (nvidia relies on the sound card and the signal carries through spdif which doesn't have the bandwidth to handle the new formats).

Thanx in advance!

 

[cmdrdredd]

Bad news for you. HDMI via PCs CANNOT handle the new DolbyTrueHD and DTS HD audio signals. You can only bitstream Dolby Digital Plus and standard DTS.

If you want TrueHD and DTS HD you have to use the analog outputs from your soundcard to your receiver and let the software (PowerDVD for example) decode the audio for you. As you said Spdif will not do HD audio either.


When it comes to video both cards will handle it the same. They have the same UVD that will process the video stream.

I researched this for a long time before I found out that the decoding is in software and passed through your soundcard's analog outputs. If you want HD audio you have to do it this way.

 

[StephenP]

I see, thanks a lot!

So, pc hdmi does not take advantage of the increaced bandwidth offered by the hdmi interface and does not output the new full res audio formats digitally... That kinda sux if you have an a/v amp that can handl the new formats as I trust the hardcoded decoding of the amp more then the software decoding and analog outputs of a soundcard.

 

[scott9343]

so if one is just going to be using the vid card for hd, no gaming, there is no benefit to picking the 2600 over the 2400?

 

[heyheybooboo]

Originally posted by: scott9343
so if one is just going to be using the vid card for hd, no gaming, there is no benefit to picking the 2600 over the 2400?

Not a great deal maybe 5% less CPU utilization.

 

[cmdrdredd]

Originally posted by: StephenP
I see, thanks a lot!

So, pc hdmi does not take advantage of the increaced bandwidth offered by the hdmi interface and does not output the new full res audio formats digitally... That kinda sux if you have an a/v amp that can handl the new formats as I trust the hardcoded decoding of the amp more then the software decoding and analog outputs of a soundcard.

Well, it has to do with the HDCP and whatever other protections are involved. Supposedly the companies who create the decoding software are working with Dolby labs and Digital Theater Systems to come up with a way to protect the audio stream from a PC. Right now it can't.