[MEncoder-users] lavc option nr

[Rich Felker]

On Mon, Jun 20, 2005 at 09:08:24PM -0700, RC wrote:
> On Mon, 20 Jun 2005 23:10:09 +0200
> Jan Paul Schmidt <jps at fundament.org> wrote:
> 
> > At the GOP boundaries a high quantiziser is used and it 
> > looks like the picture have a sort of pump effect
> 
> nr seems to confuse the ratecontrol.  Try your sample after 2 or 3
> passes (not just one) and it should use a higher quantizers there, and
> looks much better.   
> 
> nr works perfectly with vqscale= if you need to do single-pass
> encoding for some reason.
> 
> I don't know what a "pump effect" is.

(S)VCD sucks bad and requires very constricted bitrates. Thus
constant-qp is not an option, and 2pass is very wasteful.

For what it's worth, I always had this "pump effect" problem even
without nr. My solution was:

-lavcopts vi_qfactor=0.1:vi_qoffset=1.5

Basically this just forces all I frames to have qp around 2-4. :)

Rich