[FFmpeg-devel] MMX version for put_no_rnd_h264_chroma_mc8_c

Christophe GISQUET christophe.gisquet
Sun Jul 8 12:20:35 CEST 2007


Kostya a ?crit :
> It could be made from put_rnd_h264_chroma_mc8_* by simply changing one
> instruction or constant but I was busy with other things to do it myself.
> Thanks for your work.

>From comparing the normal and no_rnd version, this indeed boils down to
a constant used for rounding, 32 or 28.

Using the code found in  dsputil_h264_template_mmx.c yields here ~2150

Using my implementation without the copy and linear filter optimizations
is 2900. Adding them brings it down to 2100, but that may vary from one
computer to another, so the difference might be discarded. Patch
attached that should help testing that.

So the next step would be how to integrate this, currently done by
copy'n'editing at the end of h264dsp_mmx.c. Having a common function
with an additional parameter to specify which rounder to use is a
possibility, but that would also affect the put_avg case.

Best regards,
Christophe GISQUET
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