[FFmpeg-devel] [PATCH 3/5] lavfi/gradfun: fix dithering in MMX code.

Michael Niedermayer michaelni at gmx.at
Tue Dec 11 08:13:52 CET 2012


On Tue, Dec 11, 2012 at 01:21:58AM +0100, Clément Bœsch wrote:
> On Fri, Dec 07, 2012 at 08:50:48AM +0100, Reimar Döffinger wrote:
> > "Clément Bœsch" <ubitux at gmail.com> wrote:
> > 
> > >Current dithering only use the first 4w instead of the whole 8 random
> > >values.
> > 
> > I think you should benchmark it, I suspect leaving the comparison in the middle instead of having the C version handle more pixels might be faster.
> 
> Yes indeed, with a width=719 it's indeed a little faster to add a
> comparison in the middle.
> 
> Note: the dithers+4 is a little ugly, any suggestion welcome (and a later
> commit to at least make it close to *dithers might be a good idea)

"r"(dithers)
and address based on that
the 2 as its now after the patch might also cause problems for some
gcc on x86-32

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

it is not once nor twice but times without number that the same ideas make
their appearance in the world. -- Aristotle
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