/me does not understand, if the vdpau one already does more than xvmc, why is it reported as slower than xv?
Most people are currently only testing the yuv->rgb and scaling part of vdpau, since this works with all supported codecs.
This stages of the rendering pipeline are just a bit slower than Xv because of the debugging overhead. If you compile the state tracker without debugging support, it should be slightly faster because we don't need to call the x server to display every frame.
But the real improvement comes only when you enable more decoding stages, with mplayer provide the "-vc ffmpeg12vdpau" option for example.
DivX and XviD are implementations of MPEG-4 Part 2, sometimes referred to as MPEG-4 ASP/SP and closely related to H.263. Decoding it is not a challenge even for low-end CPUs, though hardware acceleration is desirable where battery power must be preserved.
MPEG-4 Part 10 or H.264, sometimes referred to as MPEG-4 AVC, is what taxes even modern and fast CPUs. High-bitrate 1080p content usually requires a multithreaded implementation or hardware acceleration.