[XviD-devel] [BUG] BFrame encoder doesn't force intra for 1st frame

[Michael Militzer]

Hi,

----- Original Message -----
From: "Christoph Lampert" <chl@math.uni-bonn.de>
To: <xvid-devel@xvid.org>
Sent: Wednesday, August 07, 2002 5:26 AM
Subject: Re: [XviD-devel] [BUG] BFrame encoder doesn't force intra for 1st
frame


> On Wed, 7 Aug 2002, Dirk Knop wrote:
>
> > Hi,
> >
> > peter ross wrote:
> >
> > > questions
> > > ---------
> > > - is anyone working on vfw codec_2pass_update() this week/weekend?
> > > this patch will change a few things.
> > > - do we want BFRAME mv-hinting??
> > >
> > I think MV hint support even for bframes would be nice, later on the
> > users would complain if they can't use it with bframes, I'm quite sure
> > about that.
>
> Especially since B-frame ME is (and will stay, even after
> optimization) much slower than P-frame ME.

I'm not sure if MV hint (as it's now) is really that good (I remember Daniel
reported that encodings using MV hint are about 5 - 10% worse than without).

I ask myself if it wouldn't give better results to do the first pass with a
lower quality mode with integer ME only (that's quality=3, right?), which
should be relatively fast and then do a normal second pass with high quality
(quality 5 or 6). This could be nearly as fast as hinted ME and could give
better results. (I suppose that sizes of quality 3 encoded frames are simply
equally larger than their equivalent quality 5 encoded ones, so the size
predictability (and quantizer calculations) for the second pass could still
work pretty well if the formula is adopted a little bit...)

Michael