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

[Guillaume POIRIER]

Hi,

On Mon, Jan 5, 2009 at 6:34 AM, Matyas Sustik <mplayer.list at sustik.com> wrote:
> I have encoded a 1080i broadcast using the following filters:
>
> pp=ci,crop=1904:1072:10:0,hqdn3d=4:3:6,softskip,scale=952:536:0:0:0.00:0.60,harddup
>
> 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
> kb/s:3259.63
>
> 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
> kb/s:3068.16
>
> 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.

I think you should try to work out this problem on x264's mailing list.

Guillaume
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