General consensus is that implementing shader-based video decode over Gallium3D makes more sense than doing a hardware-specific implementation for every different GPU family. The current focus on 3D work reflects that :
Classic 3D => Gallium3D => video decode over Gallium3D
One thing I haven't had time to check is whether XvMC can be useful for H.264 and VC-1 if only the MC portion of the API were used (ie not IDCT, where the MPEG-2 coefficients definitely won't work). My guess is that XvMC in its current form simply won't fit with the newer video formats, so there's a strong argument for implementing a Gallium3D backend directly in the existing decoder stacks.
Last edited by bridgman; 09-08-2009 at 08:33 AM.