Re[5]: [XviD-devel] GMC

Wed, 6 Nov 2002 01:05:59 +1030

Hi,

> We cannot "turn off" GMC. But if GMC is enabled we still can choose to use
> P_VOPs (which don't have support for GMC) or S_VOPs (which have support).
> This _must_ be supported by the decoder!

>> Anyway, it seems we can't turn GMC off for the time being...

> Maybe your routine didn't check if the VOP was S-VOP or P-VOP?
> The _decoder_ surely should check, because S-VOPs have to be decoded
> differently. Btw. which decoder do you use?

Yes it checked. I have no idea what caused this. I decoded with
ffdshow and divx5, with identical effect.

> In my oppinion any frame with GMC should have at least as many NOT_CODED
> blocks as without GMC. Otherwise it's "bad".

You're right, I'll try to alter my GME search to maximize number of
blocks with SAD below skip threshold. I can play with it - current
version is just a skeleton so that I have any GMC vector at all.

Currently, my function gives an astionishing 0.05% filesize decrease ;P

I can now 100% confirm that there is a chroma shift when using gmced
macroblocks :(

Radek