[M4IF Technotes] size of block required from the reference frame for GMC?

[Deepali Arya]

Hi,
Thanks for the response to the conformance question. It makes a lot of sense
when the requirements are put explicitly like that.
I also have a question about the GMC implementation in advanced simple
profile (ASP).  What is the largest block of reference data that can be
required for GMC  ( i assume this would be the case of affine transformation
)? For eg. the maximum predictor block size that half-pel motion
compensation would need would be 17x17 for 1-MV case. Can such a limit be
put on the GMC predictor data too ? I have run the ASP verification
bitstreams in the reference decoder, and came up with a block size of 22x22
for GMC - but such a size is not intutive from the warping functions, and I
was curious if I can put a maximum limit on the block needed?
Thanks.
Deepali Arya
Improv Systems Inc, Beverly.
Email: deepalia   improvsys.com
Tel:  (978) 927-0555 x18