MOSCOW: The Graphics and Media Lab at Moscow State University recently released the results of its comparison of Google’s WebM VP8 codec with MPEG-4/H.264. VP8 is a royalty-free, open-source codec recently released by Google for compressing online video. H.264 encoders are fee-based.
The release of VP8 sparked an ongoing debate about its quality compared to that of H.264. The Moscow lab used an MPEG-4 x264 encoder for the tests, which involved movie clips and HDTV, and used the structural similarity index, or SSIM. (Image is a frame from the movie “Troy,” used for sharp scene changes and difficulty in compressing small details.)
“Bitrate handling for the VP8 encoder for HDTV is quite good, except the ‘Troy’ sequence at low bitrates,” the results said. With regard to movies: “When comparing VP8 and x264, VP8… shows five to 25 [times] lower encoding speed with 20 to 30 percent lower quality at average. For example, x264 high-speed preset is faster and has higher quality than any of VP8 presets at average.”