[MPlayer-users] lavc psnr mixup

Michael Niedermayer michaelni at gmx.at
Wed Sep 8 12:12:44 CEST 2004


On Wednesday 08 September 2004 00:48, Loren Merritt wrote:
> The PSNR values in the psnr_*.log generated by mencoder/lavc seem to be
> matched up to the wrong frame numbers. This occurs consistently on all
> input videos and all lavcopts, including different vcodec's.
> The offset is (3 + vmax_b_frames), and happens in display order, even
> though stats are output in encoded order.
> The other stats (qp, size, frame type) are matched to the correct
> frame number.
> The PSNRs that get bumped off the end due to this offset are not used
> when calculating the PSNR summary printed by mencoder, but the "inf"s
> inserted at the beginning are also not counted in that summary.
> I had a quick look in the source, but couldn't find anywhere (either
> in ve_lavc.c or in libavcodec/) that the psnr computations referred to
> any frame other than the current.
> Version:
> MEncoder dev-CVS-040906-23:51-3.3.1 (C) 2000-2004 MPlayer Team
> Example:
> I constructed a video of 8 identical high complexity frames followed by 8
> identical low complexity frames.
> $> mencoder in.avi -ovc lavc -lavcopts vqscale=2:psnr:keyint=1
> $> cat psnr_150806.log
>      0, 2.00,  65322, inf, inf, inf, inf I
>      1, 2.00,  65322, inf, inf, inf, inf I
>      2, 2.00,  65322, inf, inf, inf, inf I

should be fixed

level[i]= get_vlc(); i+=get_vlc();  (violates patent EP0266049)
median(mv[y-1][x], mv[y][x-1], mv[y+1][x+1]); (violates patent #5,905,535)
buf[i]= qp - buf[i-1];    (violates patent #?)
for more examples, see http://mplayerhq.hu/~michael/patent.html
stop it, see http://petition.eurolinux.org & http://petition.ffii.org/eubsa/en

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