We do have rdar://6430376 listed for the issue originally mentioned at the start of this thread. We created a special version of the QCTV example for demonstration.

Greetings,

Florian Albrecht
Boinx Software.


On 10.02.2009, at 05:10, Troy Koelling wrote:

Of course it never hurts to have duplicate bug reports filed so the decision makers know what priority to give, however this is a known problem from the last time it came up.

Sent from my iPhone

On Feb 9, 2009, at 7:01 PM, Michael Diehr <[email protected]> wrote:

Is anyone able to submit a proper bug report on this? I'd be happy to try, but I think my report would be lacking in details "QC on NVIDIA chips is bad, mkay...uh...pls fix it"?

I'd hope that a proper bug report, one that suggest the right fix(es) could get some attention?

On Feb 9, 2009, at 3:15 PM, vade wrote:

A little birdy mentioned this has to do with the image channel ordering, and that the ATI drivers automatically swap the channels to the necessary ordering to make things faster, using a shader on the GPU. Apparently, something is sub optimal with ATI for this.

Maybe its specific to QCs opaque handing of images (QCImage datatype), but ive head that this holds true for other apps.

your tests seem to confirm this, and my testing on a colleagues new MBP is that while its faster than the older NV 8600M hardware, my x1600 still stomps it for CI/Video pipeline processing.

The Raw GL calls though (vertex drawing/filling etc), are much much faster than my x1600, so its a give and take.

On Feb 9, 2009, at 4:36 PM, Michael Diehr wrote:

Your benchmarks corelate with vram also. Have you tried 8600M with the same vram as the ati cards?


We are just testing the ones we have, and don't have that particular combo.

The tests we are doing should not be taxing VRAM, i.e. we are using 720x480 internal pictures which works out to under 2MB per image, and only a dozen or so images max. So I don't think we are running out of VRAM.

I just ran another test comparing the ATI 1...@256mb vs. the NVIDIA 8600 @ 128MB, this time doing a very simple test (3 video inputs overlayed). Results: ATI = 30fps, NVIDIA = 18fps. Again, 3 x 2MB per frame images should not be getting anywhere near to 128MB VRAM total.

Now, perhaps the 256MB version of the 8600 has not only larger VRAM but faster VRAM as well, in which case it'd perform better? Still, my gut feel is that the NVIDIA chips or drivers are not well suited for QC based on what I've seen.


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