[Ffmpeg-devel] [PATCH] Vorbis sse fix

[Balatoni Denes]

Hi!

h?tf? 30 m?jus 2005 02.05-kor Rich Felker ezeket a bolcs gondolatokat 
fogalmazta meg:
> On Sun, May 29, 2005 at 11:51:20PM +0200, Diego Biurrun wrote:
> > On Sun, May 29, 2005 at 09:34:11PM +0200, Balatoni Denes wrote:
> > > This patch fixes xmmintrin.h support detection for me (gcc 3.3.6
> > > (Debian 1:3.3.6-5)), and adjusts the vorbis decoder so that buffers are
> > > adequately aligned. The decoder - by my estimation - is roughly 10 %
> > > faster then the reference implementation on my p4.
> >
> > Are you referring to libvorbis?  I assume yes.
> >
> > Has anybody else benchmarked ffvorbis?
>
> I dunno, about tremor is roughly 50% faster than libvorbis, at least
> with the low-precision mode enabled.

Yes, that explanation is here:
http://en.wikipedia.org/wiki/Amd#NexGen_.2F_K6
where it says "While it matched (generally beating) the Pentium II/III in 
integer operations, the FPU was a non-pipelined serial design and could not 
compete with Intel's more advanced FPU architecture."

On another note eg. most personal music players (or what are they called, like 
ipod etc.) don't have an FPU, so of courtse a fixed-point implementation 
would be good to have. The only thing left is writing a fast integer imdct 
from scratch.

>
> Rich

bye
Denes

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