Talk:GSoC - GPU Assisted Video Decoding
What about Motion Compensation?
Checkout this other GSoC project which aims to implement GPU Assisted Video Decoding by implemning XvMC support into Gallium 3D. Maybe you could look into doing the same but instead implement VAAPI into Gallium 3D and then write your GLSL Pixel Shaders for VAAPI? http://www.bitblit.org/gsoc/gallium3d_xvmc.shtml