[MEncoder-users] Fwd: Questions on Mencoder performace

[Phil Ehrens]

Dominik 'Rathann' Mierzejewski wrote:
> > 
> > None of these things will give you as big a performance boost as
> > switching from xvid to lavc will. Using '-oac copy' will also give
> > you a performance (and quality) boost. Good starting options for
> > lavc:
> > 
> > -lavcopts vcodec=mpeg4:nr=1000:mbd=2:v4mv:trell:vpass=N:vbitrate=1800
> 
> nr=1000 is a bit too much. I wouldn't go higher than 400, 600 tops.
> I'd also add mv0 and cbp to the mix.

I've done pretty extensive testing of nr, and 1000 has not been too
much on very clean dvd source, very noisy dvd source, or any dvd
source at all. So, for transcoding from dvd source, I would continue
to recommend nr=1000. All my tests were 2-pass encodes to lavc
mpeg4. There were NO detectible artifacts. If you use nr on single
pass encodes the behaviour is bizarre, I don't recommend it.

mv0 and cbp look interesting, I don't know how I overlooked them!
I'm testing them now. They look like they are potentially useful
in my single pass mpeg4 -> dvd transcodes as well.

It certainly would be nice to know quantitatively what the different
effect is between nr=100, nr=1000, and nr=10000.