[FFmpeg-devel] [PATCH] VP8 MMX optimizations (MC and IDCT dc_add)

Ronald S. Bultje rsbultje
Tue Jun 22 21:35:40 CEST 2010


Hi,

as per $subj.

Speed gain:
- dc_add goes from 1800 to 1350 cycles (where 1150 is overhead,
measured as empty asm func), so about 3-3.5x faster.
- The MC functions are each about 4-5x faster (I only measured the 4x4
ones, the rest I assume are similarly faster but not measured).
- Total time spent on a shell-script that decodes the whole testsuite
(vp8-test-vectors-r1, file 001-017) including shell overhead and
everything goers from 2.3 to 2.1 seconds with these applied.

Results are bit-identical, and this is my first MMX/etc. ever! Thanks
to Jason for teaching me. ;-).

Ronald
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