[MPlayer-dev-eng] check recommended MPEG2 encoding options

[Jeff Clagg]

On Tue, Mar 06, 2007 at 10:12:28AM -0800, RC wrote:
> On Tue, 6 Mar 2007 00:43:25 +0100
> Reimar D?ffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> wrote:
> 
> > -lavcopts
> > vcodec=mpeg2video:vrc_buf_size=1835:vrc_maxrate=9800:vbitrate=8000:\
> > keyint=15:trell:mbd=2:precmp=2:subcmp=2:cmp=2:dia=-10:predia=-10:cbp:
> > mv0:\ vqmin=1:lmin=1:dc=10:vstrict=0
> > 
> > Can someone double-check this a bit?
> 
> It's completely wrong, and I have no idea why it was suggested.
> 
> The most glaring mistake is using *cmp=2, which causes extreme
> blockiness.  Practically no stand-alone DVD/SVCD/VCD players do
> postprocessing, so it's just going to look horrible, no matter what.
> The default (cmp=0) will look far better.  Either that or *cmp=3 should
> be recomended.
> 
> cbp and mv0 also appear to make blockiness worse in my tests (but not
> by much).  No idea about dc.

If I can pipe in - the main "usefulness" of dc=10 here is to waste bits 
in exchange for a relatively tiny quality gain. It's probably not worth 
it, but may satisfy the "I want to fill up every sector of the DVD" 
crowd.