[Ffmpeg-cvslog] CVS: ffmpeg/libavcodec ratecontrol.c, 1.50, 1.51 mpegvideo.c, 1.494, 1.495 mpegvideo.h, 1.227, 1.228

[Guillaume POIRIER]

Hi,

On 12/27/05, Corey Hickey <bugfood-ml at fatooh.org> wrote:
> Michael Niedermayer CVS wrote:
> > Update of /cvsroot/ffmpeg/ffmpeg/libavcodec
> > In directory mail:/var2/tmp/cvs-serv5393
> >
> > Modified Files:
> >       ratecontrol.c mpegvideo.c mpegvideo.h
> > Log Message:
> > use correct qp & lambda for ME on the second pass
>
> Now that I'm done fixing my car... :)
> ...I'm finally getting around to testing Michael's recent improvements.
> More updates from me will come over the next few days.
>
> -----------------------------------------------------------------
> for i in 1:turbo 2 ; do
>   time mencoder ~/dumpstream/matrix.vob -aid 128 -oac copy \
>   -vf crop=718:356:0:60,scale=640:272 -sws 9 -ovc lavc -lavcopts \
> vcodec=mpeg4:vbitrate=581:psnr:vpass=$i:mbd=2:mv0:trell:cbp:\
> precmp=2:cmp=2:subcmp=2:predia=2:dia=2:preme=2:vme=5:v4mv:\
> last_pred=2:vqcomp=0.6:vmax_b_frames=2:qpel -ofps 24000/1001 \
>   -o test.avi
> done
>
> -----------------------------------------------------------------
> before:
>
> (pass 1)
> PSNR: Y:40.03, Cb:44.35, Cr:44.66, All:41.08
> user    34m12.485s
>
> (pass 2)
> PSNR: Y:42.10, Cb:45.16, Cr:45.86, All:42.96
> user    188m44.869s
>
> -----------------------------------------------------------------
> after:
>
> (pass 1)
> PSNR: Y:40.03, Cb:44.35, Cr:44.66, All:41.08
> user    34m38.232s
>
> (pass 2)
> PSNR: Y:42.11, Cb:45.17, Cr:45.86, All:42.98
> user    188m52.138s
>
> -----------------------------------------------------------------
> The differences in encoding time are negligible -- I'm using this
> machine for random other stuff meanwhile, so the margin of error is
> probably a few minutes large.
>
> In accordance with what Michael wrote, there isn't a significant quality
> improvement. Though the "before" and "after" encodes are visibly
> different in high motion scenes, I can't really say which is better.

Good, that's quite nice! I note that you did not use latest bframe
strategy (=2). I also note that the improvement is not as huge as in
the commit message:

hmm did i mess the scaling of these up at some point?
anyway, this change decreases bitrate and increase PSNR by ~1.00 on my
test file, other files also benefit significantly

Is your build from before or after this commit?

Guillaume
--
Life is pleasant. Death is peaceful. It's the transition that's troublesome.
    Isaac Asimov (1920 - 1992)

MPlayer's doc is offline. Find some fresh one here:
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http://tuxrip.free.fr//MPlayer-DOCS-HTML/fr/