[FFmpeg-devel] [Issue 664] [PATCH] Fix AAC PNS Scaling

[Michael Niedermayer]

On Fri, Oct 10, 2008 at 12:15:30PM +0100, Robert Swain wrote:
> 2008/10/8 Michael Niedermayer <michaelni at gmx.at>:
> 
> [...]
> 
> > so it seems the gcc version makes a very significant difference as well
> 
> It seems there isn't really a good all-round solution here. What shall
> we do? I would be inclined to look toward the future and use doubles
> for the sums and sqrtf() as this performs best on a modern CPU with
> GCC 4.3, but what do you think? I suppose less powerful older cpus
> would need better performance more, but obviously ideally we would
> want to use whatever is best on the machine in question. Maybe a macro
> and configure time testing/identification and mapping based on CPU?

Iam still thinking that 1 second of normalized random vectors might be
worth considering. That would avoid the sqrt() completely unless iam
missing something.

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

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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