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

["Radoslaw 'sysKin' Czyz" <syskin@xxxxxxxxxxx>]

Hi

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.

It looks like chroma components are taken from random memory
positions.

I removed this part with #ifdef BFRAMES, changed it to "#else" part
(i.e. changed image-based to block-based compensation ) and the
artifacts are gone. 

However, I'm still not very sure if the bug is really there:
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.

I definitely have no idea what this compensation is all about (why
changing for B frames ??), so I'd need someone who knows it to take a
look and check if there is no stupid mistake.

I'll try to look at it myself, too

Radek