[FFmpeg-devel] [RFC] integer.h overhaul

Stefano Sabatini stefasab at gmail.com
Sat Oct 13 00:30:12 CEST 2012


On date Friday 2012-10-12 05:28:58 +0200, Michael Niedermayer encoded:
> On Thu, Oct 11, 2012 at 10:47:36AM +0200, Stefano Sabatini wrote:
[...]
> > Implemented the first suggestion (which has the nice property that no
> > API/ABI is even exposed).
> 
> > Problem is, the code is too slow, xface
> > takes several seconds to encode an image, which is not acceptable.
> 

> I dont think the original xface code is that slow (given its age if i
> dont misremember that), so why dont you use that ?
> but i didnt search/look at the code so maybe theres some problem iam
> unaware of
> 
> integer.c/h isnt optimized to be used as an arithmetic coder

The original code is fast since it implements a specialized algorithm
(it just operate on bigint+uint8_t). I tried to rely on a more generic
algorithm and leverage already existing code, but eventually came to
the conclusion that a specialized algorithm is good enough (and
possibly the only fast enough solution) for my purposes.

Patch dropped.
-- 
FFmpeg = Frenzy and Friendly Majestic Proud Entertaining Goblin


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