Reynod :
An excellent read though Andrew.
Please give us an update in a few months to see if there has been any noticeable improvements ... keep your base files for reference.
I would imagine Quicksynch is now a major plus for those interested in rendering ... and AMD and NVidia have some work to do.
I appreciate the time and effort you put into the research and the depth of the article.
Thanks,
Will do, but I think overall this article sums up everything in a way that it's relavant for months to come. (Well, it's my hope it did anyways). "In a worst-case scenario, hardware acceleration gives you 75% of the quality and a minor speed up versus processor-only transcoding. In a best-case scenario, you are getting 99% of the quality, and running up to 400% faster than a processor working on its own." The difference is that in a few months, the worse case will likely be up to 80%, 90%, or even 99%.
There is always going to be some sort of trade off, and for the majority of us, 99% quality preservation at 4x the speed is well worth the benefit. The problem is that there is virtually no way to compare transcoding software or even GPGPU hardware (or software) without introducing new variables to testing. You need to accept all the variables and treat the problem like a puzzle grid.
I would add there is so much more to image quality than what we talked about. We didn't even discuss LCD hardware or colorspace. I think this article changes the game a bit. I think we have gotten so use to seeing tearing, blocking, or some video artifact and then we simply blame the video encoder without a second thought.
If you read many of the sandy bridge articles on the web, people were simply saying "that video looks fuzzy" in very specific cases and then labeled Quick Sync or CUDA poor at transcoding as a result. While the video they saw was fuzzy, that doesn't automatically make it a transcoding error. It could have been a renderer or decoder problem. For example, if bitrate dropped off suddenly, its possible that a specific decoder wasn't cable of keeping up. This was a major point we were trying to make. Those automatic claims are invalid if they didn't cross check the problem to isolate decoders and renderers.
Hell, you can't even rely on the same trancode path. If you rerun a trancode, the randomness (due to parallelism) can cause an visible error you didn't see in the first transcode, even if you use the same hardware and software config
Cheers,
Andrew Ku
TomsHardware.com
, Fix your links. 
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