[MEncoder-users] two pass encoding with pullup

[Guillaume Poirier]

On Apr 5, 2005 4:26 PM, Guillaume Poirier <poirierg at gmail.com> wrote:
> Hi,
> 
> On Apr 5, 2005 3:10 PM, Winterbird <winterbird at anime-avatar.net> wrote:
> > Hans-Carl Oberdalhoff wrote:
> > >Am Dienstag, 5. April 2005 08:58 schrieb Winterbird:
> > >You should also leave the bitrate (rather: all lavc-options) the same on both
> > >passes!
> > >Only exception: If you want the first pass to be fast, you can use the
> > >"turbo"-option on it. This will deactivate cpu-intensive options, without
> > >screwing 2pass up.
> > >
> > >
> > OK... Acctually I thought that the bitrate didn't really matter in the
> > first pass...
> 
> It does, but not _that_ much. Please have a look at Loren's
> explanation of how to tweak 2-pass rate control at
> http://www.mplayerhq.hu/DOCS/tech/encoding-tips.txt
> Basically, you might what to encode first pass at constant quant if
> the final movie ends up being encoded with a similar average quant,
> and if you tweak a bit the option vqcomp.
> As far as I'm concerned, I encode first pass with a constant quant of
> 2, and set vqcomp to 0.7.
> Then in the second (an up) passes, I use the "normal" bitrate.
> That might be suboptimal, but I've been quite happy with the results I've had.

That wasn't clear I think, but vqcomp=0.7 is to be set in all passes AFAIK.

Guillaume