[FFmpeg-devel] ZMBV Improved Motion Estimation

[Michael Niedermayer]

On Sun, May 11, 2008 at 02:55:43PM -0700, Jason Garrett-Glaser wrote:
> > if(histogram[0] || src[-stride]!=src2[-stride2])
> >    sum += 256*(bw*bh - histogram[0]);
> > return sum;
> >
> > should achive the same without the larger memset()
> 
> Does ZMBV support blocks larger than 16x16? 

yes


> If so, this (and the
> current code, too) will break for such blocks.

yes

The question is how much do we gain from larger blocks?
If its nothing or negligible then i think its better if we just
ignore larger blocks and not bother coming up with complex or slow
code ...

Also note that for smaller blocks the memset(0) will eat the overwhelming
majority of the time. zeroing 256 elements vs. a loop with 4*4 iterations ...

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

There will always be a question for which you do not know the correct awnser.
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