[MEncoder-users] MPEG2 quality

[Levente Novák]

On Mon, 2007-03-05 at 22:14 +0100, Reimar Döffinger wrote:
> Hello,
> On Mon, Mar 05, 2007 at 09:45:17PM +0100, Konrad Dubiel wrote:
> > When encoding DV video into MPEG2 I get blocky compression artifacts
> > in flat coloured areas. They are clearly visible and very annoying.
> > 
> > My -lavcopts are:
> > vcodec=mpeg2video:\
> > trell:mbd=2:precmp=2:subcmp=2:cmp=2:dia=-10:predia=-10:cbp:mv0:\
> > vqmin=1:lmin=1:dc=10:vstrict=0:\
> > vrc_buf_size=1835:\
> > keyint=12:\
> > vrc_maxrate=9800:\
> > vbitrate=8000:\
> > aspect=16/9:\
> > acodec=ac3:abitrate=224
> > 
> > Is this really the best quality mencoder can achieve? It is very poor
> > when compared to MainActor for example.
> 
> I really wonder where you got those from, many of those are likely to
> decrease quality, esp. the dia, predia, dc, vqmin, lmin options seem
> like a very bad idea. About the cmp settings I have my doubts as well.
> But anyway, one-pass bitrate-based encoding will almost always result in
> crap, you must do at least two passes.
> And why not using vmax_b_frames and vb_strategy?
> 

These are the options suggested by the docs of MPlayer/MEncoder
(encoding guide), which are supposed to _increase_ the quality.

Levente