It would be nice if you could give us an idea of what it will take to get support for this in, say, the r600g driver. I am under the impression that the ideal for Gallium3D is that you don't need any driver-side work in order to support things like this. Of course, given the relative youth of Gallium3D, one could imagine that this MPEG4 Part 2 support might exercise the drivers in ways they haven't been exercised before, necessitating new code and bugfixes. I would appreciate it if somebody could list at least some of those necessary features and bugfixes.
My 8 years old machine can decode high definition DivX/XviD/MPEG4p2 on the CPU without breaking a sweat; doing this on a modern machine is a joke resource-wise.
If someone's doing this for fun - fair enough, but it is a waste of time and resources which could have been allocated elsewhere. (*cough* H264 decoding *cough*)
YOU are useless.
In order to perform mpeg4p2 decoding, you need to implement A, B, C, D, E, F, and G.
In order to perform H264 decoding, you need to implement A, B, C, D, E, F, G, H, I, J, K, and L.
So you start by implementing A->G, which has to be done ANYWAY, test it, and then do the rest.