[Ffmpeg-cvslog] CVS: ffmpeg/libavcodec mpegvideo.c,1.496,1.497

Corey Hickey bugfood-ml
Tue Dec 27 18:19:03 CET 2005

Michael Niedermayer CVS wrote:
> Update of /cvsroot/ffmpeg/ffmpeg/libavcodec
> In directory mail:/var2/tmp/cvs-serv20080/libavcodec
> Modified Files:
> 	mpegvideo.c 
> Log Message:
> improved lambda/qp guessing for motion estimation RD in first pass
> this only affects encoding with bframes and rate control

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 \
last_pred=2:vqcomp=0.6:vmax_b_frames=2:qpel -ofps 24000/1001 \
  -o test.avi


(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


(pass 1)
PSNR: Y:40.05, Cb:44.34, Cr:44.64, All:41.09
user    34m55.052s

(pass 2)
PSNR: Y:42.10, Cb:45.17, Cr:45.85, All:42.97
user    190m5.245s


As is to be expected, low motion scenes look identical. I thought high
motion scenes looked nearly identical as well, until I ran into a couple
places that looked much worse after this patch. I'm uploading four
representative screenshots (two before, two after) to:


I'm on a slow dial-up connection right now, so this message might reach
the mailing list a few minutes before the upload finishes.

I haven't checked any later commits; these problems might disappear when
I try them.


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