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Pierre B. · Nov 17, 2003, 07:29 AM

Well, it appears that the new DVD player in Panther, relies still on the CPU to do its decoding. However, all (I think) current Apple hardware is equipped with GPU's capable to decode MPEG-2. I wonder why Apple does not offer at least as option hardware MPEG-2 decoding in the new DVD player. The benefit from freeing the CPU is quite obvious. Does anyone know why? Are there third-party solutions enabling hardware decoding?

Ludovic Hirlimann · Nov 17, 2003, 08:57 AM

Originally posted by Pierre B.:
Well, it appears that the new DVD player in Panther, relies still on the CPU to do its decoding. However, all (I think) current Apple hardware is equipped with GPU's capable to decode MPEG-2. I wonder why Apple does not offer at least as option hardware MPEG-2 decoding in the new DVD player. The benefit from freeing the CPU is quite obvious. Does anyone know why? Are there third-party solutions enabling hardware decoding?

Why don't you give some feedback to Apple ?
Maybe because they need to support legacy hardware with not DVD enabled GPUs.

Big Mac · Nov 17, 2003, 03:38 PM

Originally posted by Ludovic Hirlimann:
Why don't you give some feedback to Apple ?
Maybe because they need to support legacy hardware with not DVD enabled GPUs.

No, I don't believe that's the case. If it were, then Apple could simply have DVD Player support hardware decoding on certain machines but not on others. Apple used to include hardware DVD decoding in its older hardware, but then it shifted to software completely. I don't know why this is the case, but it seems like a conscious decision was made not to rely on hardware. It really doesn't make sense to me either, but maybe it makes things easier for Apple's programmers.

bmedina · Nov 17, 2003, 07:54 PM

The shift to Quartz Extreme changed everything. DVD Player.app still takes advantage of hardware support where available, but no cards have full MPEG2 decoder subsystems anymore.

Pierre B. · 02:01 AM

Originally posted by bmedina:
The shift to Quartz Extreme changed everything.

Yes, but still DVD player eats up about 30-35% of CPU cycles.

DVD Player.app still takes advantage of hardware support where available, but no cards have full MPEG2 decoder subsystems anymore.

Sure they have (unless you include audio). Look for example the VPE tech. brief of the Geforce4 Go used in the powerbooks. nVidia claims that a Geforce4 Go can reduce CPU utilisation, during DVD playback, from 45% which is typical in a notebook, to less than 15%. So it is possible, simply Apple chose to not do so. The problem could be differences in implementation of the decoding algoritmhs according to the vendor (ATI or nVidia), so completely relying on software gives a simple (although not efficient in a notebook) solution. But I am not sure.

Certainly, Quartz Extreme is the right direction, but I have the feeling that current notebook GPU's can further improve the DVD playback experience.

bmedina · Nov 18, 2003, 10:33 AM

I meant Quartz Extreme changed things for the worse. Features that are supported in the 2D pipelines of video cards are no longer available. Since Quartz uses the 3D pipeline of the video card, support for DVD playback hardware has to be availabe for that mode.

And the link you showed states that their implementation does not allow full playback MPEG2 without a CPU hit. You'll find that the new DVD Player.app also uses some hardware features to assist in decode.