[MPlayer-users] lavc vs. xvid (and improving lavc quality)

[Jan Knutar]

> I never use postproc and I never see blocks. BTW perhaps you're
> (stupidly) using vqscale= rather than bitrate/2pass encoding. There
> may very well be a bug in the constant-quantizer code that's ruining
> quality, since none of us who encode the right way (2pass) are
> noticing any problem whatsoever...

Lavc makes it easy to shoot yourself in the foot:

-lavcopts vcodec=mpeg4:mbd=2:v4mv:trell:cbp:qprd:vqscale=2
=> Results in broken stream with lots of artifacts
-lavcopts vcodec=mpeg4:mbd=2:v4mv:trell:cbp:vqscale=2
=> ok!
-lavcopts vcodec=mpeg4:mbd=2:v4mv:trell:cbp:qprd:vbitrate=8000 (2 pass)
=> ok!