[afhof]

His blog is very insightful. There is also another great post where he talks about how to cheat on video comparison tests ( http://x264dev.multimedia.cx/archives/472 ). One of the things brought up in there is for still frame comparisons. If the frame came from an I frame rather than a B* or P frame in the output video, the test will be unfair.

*VP8 doesn't have B frames, similar to the h.264 baseline profile.