They (xiph) did a mistake when measuring the psnr. That lowered the results by more than 4 dB for x264.
"Turns he out he did everything correctly... but he used ffmpeg for outputting the raw y4m file to have its quality measured by dump_psnr (but not for theora). Apparently, ffmpeg flags the output chroma as "420mpeg2" instead of "420", which results in over 4db of PSNR being slashed off of x264's results unfairly."
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I would have guessed it was it only VLC that mac users download from sourceforge... I have many friends with mac's, and they all use VLC.
They (xiph) did a mistake when measuring the psnr. That lowered the results by more than 4 dB for x264.
"Turns he out he did everything correctly... but he used ffmpeg for outputting the raw y4m file to have its quality measured by dump_psnr (but not for theora). Apparently, ffmpeg flags the output chroma as "420mpeg2" instead of "420", which results in over 4db of PSNR being slashed off of x264's results unfairly."
http://www.reddit.com/r/programming/comments/8iphn/theora_encoder_improvments_comparable_to_h264/?sort=hot