[FFmpeg-devel] [PATCH] modification of the MMX H264 MC chroma functions to support RV40

Mathieu Velten matmaul
Thu Dec 25 18:03:32 CET 2008

2008/12/23 Mathieu Velten <matmaul at gmail.com>:
> 2008/12/23 Michael Niedermayer <michaelni at gmx.at>:
>>> or use a bigger rv40_bias table and use a shift to find the >>3
>>> variant in the table ?
>> yes
> I still don't know how to do.
> I don't want to use the rv40 table inside dsputil_h264_template_mmx.c
> if possible to do not pollute h264 code with a rv40 table.
> I can use a bigger table before the call of the function and I pass
> rng_reg and rng_reg_div_8 as arguments, but I am not sure it will be
> faster.

I don't think a single instruction which is only for the 1 dimensional
case and which is only execute once per function call (not in the for)
is a big deal, and it will be a mess if I try to use a table.

attached a cleaner patch (remove non related code, I will add this
code in a much proper way in a later patch).

I ported the h264 qpel mmx optimizations to the rv40 decoder, I will
submit a patch as soon as this one is accepted.
about 23% overall speed-up for my trunk against the current svn :)

Mathieu Velten
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