[XviD-devel] motion compensation->inter4v->BFRAMES->chroma bug?

[Marc FD]

I can do some screen-shots, give an .avi with the problematics passages (in
vertical only or horizontal only motion !!!!) or give you more info if you
need.
a another version without BFRAMES activated did not create artifacts...
I've tried to add frame_drop_ratio support (in core & vfw) without BFRAMES
flag, but it's harder than i thought.....

MarcFD  marc.fd@libertysurf.fr

> > > It seems that there is a bug of some sort. It's in motion compensation
> > > (I'm pretty sure of it), when it handles chroma components in inter4v
> > > mode AND BFRAMES is #defined.
> >
> > > If I force all macroblocks to be inter - no bug.
> > > If I force all macroblocks to be inter4v - no bug. (!)
> > > If I mix them in any way (even random) - ugly bugs show up. They are
> > > in chroma only. They dissappear if I force block-based uv
compensation.
> >
> > It was the no-halfpel fix. Inter blocks always had block-based
> > compensation (so that no-halfpel mode works) but inter4v had
> > image-based.
> >
> > The mix does not mix. Don't ask me why. You have to use block based
> > for both, or image based for both.
> >
> > Radek
>
> ARGH !!
> I'm getting chroma bugs too, and they seem related to ME too  !!!
> dunno exactly where it comes from (need to sleep before i check that ;)
> i was using a BFRAMES build with some other changes...
> in encoding everything set to defaults....
> it's killing me, because the build i've made gived me 10% improvements
> in compressibility at quant2 vs Koepi's (because of the content : anime)
> AND I DONT NEED BFRAMES. in fact i wanted to use frame_drop_ratio and
> i need BFRAMES for that. i would be very happy if you fix it.
>
> sad&asleep,
> MarcFD  marc.fd@libertysurf.fr
>