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

[Corey Hickey]

Guillaume POIRIER 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?

I'm comparing builds with and without each specific commit to which I
reply -- so, right before and right after. I haven't gotten up to the
commit you mention.

I'm ignoring vb_strategy=2, bidir_refine, and brd_scale until I catch up
with the present. Then, I'll test the impact of each new feature.

-Corey