[MPlayer-users] one-pass encoding results better than two-pass

Matyas Sustik mplayer.list at sustik.com
Mon Jan 5 06:34:03 CET 2009

I have encoded a 1080i broadcast using the following filters:


with bitrate set to 3000.  On a 20 seconds long sample the one pass encoding
produced a file with 8703945 bytes and quality:
x264 [info]: SSIM Mean Y:0.9805128
x264 [info]: PSNR Mean Y:44.861 U:48.798 V:49.399 Avg:45.849 Global:45.537

The two pass encoding (same filter and x264enc options) produced a file with
9437678 bytes.
x264 [info]: SSIM Mean Y:0.9803121
x264 [info]: PSNR Mean Y:44.632 U:48.669 V:49.280 Avg:45.642 Global:45.489

So it would seem from this experiment that the one pass encoding produced a
smaller file with the same or better quality.  (Visual inspection cannot tell
them apart.)  Am I doing something wrong?  This is not what one would expect,
right?  Should I rerun this with other samples?  The current one had a lot of
fast moving actions.

Every hardware eventually breaks.  Every software eventually works.

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