[FFmpeg-devel] [PATCH] MMX VP3 Loop Filter
Wed Oct 8 07:59:27 CEST 2008
On Oct 7, 2008, at 5:43 AM, Jason Garrett-Glaser wrote:
>> Here's an 8-bit version. However, checking for the C fallback
>> negates the
>> small speedup on my Penryn compared to the 16-bit version.
> Most of the code is still 16-bit. Are you sure this can't be done
> x264-style with emulation of extra bits and 8-bit math (reference for
> an example of how to do this: common/x86/deblock-a.asm in x264 tree)?
> This would eliminate the need for all unpacks, all packs, and all
> multiplication, and probably increase speed dramatically. I strongly
> suspect that it can be done, as the deblocking formulas seem very
> similar to those used in H.264.
It seems like you're right; the only difference between DEBLOCK_P0_Q0
and VP3 is a *3 vs. a *4 in H.264.
I don't quite fully understand x264's implementation, so it'll take
another bit to adapt it.
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