Re[2]: [XviD-devel] Global Motion Compensation

[Radek 'sysKin' Czyz]

> since you seem to develop in windows you could easily "abuse" ffdshow to
> check whether you're doing things right, just use normal halfpel ME and
> add your GMC, set FourCC to DX50 - if it decodes correct you could
> assume your implementation is correct, too ;) (or use momusys decoder on
> raw bitstream...)

Koepi, you overestimate me ;)
All I did is a function which finds a camera-panning vector and
prints it to a file :P

I'm just happy it appears to do that correctly.

I have no idea how to put this information to the bitstream - well I'm
pretty sure there is a bit which says if the VOP is GMC-ed, followed
by some values. There also must be another bit in every macroblock
(mcsel or sth)... Well I do have Video Verification Model o I'll look
for it.

> the 1-3 reference points are in 1/2 pel resolution
> btw, these referenece points specify the corners of the new image in the
> reference image

Hmm OK. So if there is only one point (translation), I have a halfpel
resolution? Is the GMC referece picture made by interpolation (so it
would just be a copy of REf, REfH, RefV, RefHV in halfpel mode - and
we have to re-compute halfpel reference in qpel mode?)) or there is
some special filter (well I guess not).

Radek