As the lead developer, I can say quite confidently that the encoder matters a huge amount more than the standard. See: http://x264dev.multimedia.cx/wp-content

As the lead developer, I can say quite confidently that the encoder matters a huge amount more than the standard. See: http://x264dev.multimedia.cx/wp-content/uploads/2009/08/quality_chart1.png http://x264dev.multimedia.cx/wp-content/uploads/2009/08/qual... http://x264dev.multimedia.cx/?p=164 http://x264dev.multimedia.cx/?p=164 http://x264dev.multimedia.cx/?p=102 http://x264dev.multimedia.cx/?p=102 As you can see, a bad H.264 encoder (e.g. Apple's) can barely compete with Xvid. The entirety of my work on x264 is contained in the past 2 years of development. The psychovisual optimizations alone probably account for at least a 50-70% improvement in compression quality.