[MEncoder-users] Why use TOOLS/calcbpp.pl and scale ?

Phil Ehrens phil at slug.org
Thu Mar 2 18:10:22 CET 2006

RC wrote:
> On Thu, 2 Mar 2006 14:43:50 +0000
> Martin Collins <martin at mkcollins.org> wrote:
> > > 4)use a denoiser filter (optional)
> > 
> > It usually saves bits but costs time.
> "-lavcopts nr" uses practically no time, and, IMHO, looks far, far
> better than any values for hqdn3d.

Note that the behavior of nr is very different in 1-pass and 2-pass
modes. In 2-pass mode it is a brilliant thing. In 1-pass mode it is
an interesting "decimation with filtering" operation that sometimes
works wonderfully and sometimes creates strange artifacts.

For single pass encodes hqdn3d will behave as expected. I sometimes
use nr in single pass encodes to reduce the size of my output, since
that is a reliable side effect of nr in single-pass mode.

It would be interesting to hear an analysis of nr's behavior in
single and multi pass modes by it's author.

Note that I do not consider nr's single pass behavior as a bug.
I believe that nr was intended to be used for multipass encoding.

If I am wrong, which I may very well be, I would like very much
to be told right by someone who understands nr well.

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