[FFmpeg-devel] [PATCH] Further optimization for vp3.c:unpack_vlcs()

Michael Niedermayer michaelni
Sun Sep 20 12:13:17 CEST 2009


On Sat, Sep 19, 2009 at 11:38:31PM -0700, Mike Melanson wrote:
> Reimar had a good idea with this patch:
>
> http://lists.mplayerhq.hu/pipermail/ffmpeg-devel/2008-June/047993.html
>
> I got rid of a bunch of other structure dereferences in the inner loop. For 
> one sample I was using (and profiling the calls to the unpack_vlcs() for 
> the DC coefficients), these are the before and after numbers:
>
> original:
> 3019769 dezicycles in unpack_vlcs (DC coeffs), 2048 runs, 0 skips
>
> faster:
> 2894529 dezicycles in unpack_vlcs (DC coeffs), 2048 runs, 0 skips
>
> Further, when using OProfile, I see unpack_vlcs()'s overall percentage drop 
> from 44.1% -> 41.9% when decoding the first 15 seconds of Big Buck 
> Bunny/1080p.
>
> -- 
>     -Mike Melanson

>  vp3.c |   24 +++++++++++++++---------

you are maintainer of the file, so i dont think i have to review this :)

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

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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