Pixel shader to encode/decode videos

[tcchiu]

http://www.ati.com/products/RadeonX1800/specs.html
"Seamless integration of pixel shaders with video in real time"

It's said that Avivo uses pixel shaders to decode the video. I am curious which part in the decoding process is done by the pixel shader. Could it be de-blocking ("Pixel Optimization" in FULLSTREAM whitepaper)?

http://www.chip.de/artikel/c1_artikel_17670022.html?tid1=9227&tid2=0
"We assume that the XCode tool mainly utilizes the programmable pixel shader units for it’s number-crunching."

What exactly the "number-crunching" thing might be?

[Simon F]

I am curious which part in the decoding process is done by the pixel shader.
I would imagine that

Motion Compensation
(Possibly)IDCT
Deblocking/Deringing

...would be candidates.

[Dave Baumann]

I believe YUV colourspace conversion is one(?).

[Rys]

Deblocking is part fixed, part programmable, rest on the CPU, iDCT is fixed function and doesn't use the programmable hardware or CPU.

Motion comp is programmable assisted, but not the entire process. YUV colourspace conversion is done using a shader program on every ATI part that has at least PS1.1 ability.

All of that is as far as I know, and only for ATI parts </disclaimer>