[FFmpeg-devel] [PATCH] AMR-WB Decoder

[Michael Niedermayer]

On Sun, Sep 19, 2010 at 10:47:23AM +0100, M?ns Rullg?rd wrote:
> "Ronald S. Bultje" <rsbultje at gmail.com> writes:
> 
> > Hi,
> >
> > 2010/9/18 Marcelo Galv?o P?voa <marspeoplester at gmail.com>:
> >> On 18 September 2010 22:27, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> >>> What "random" number generator does the ref decoder use? Is it an algo
> >>> that you can copy, or is it literally "random()"?
> >>
> >> It is simple:
> >>
> >> Word16 D_UTIL_random(Word16 *seed)
> >> {
> >> ? /*static Word16 seed = 21845;*/
> >> ? *seed = (Word16)(*seed * 31821L + 13849L);
> >> ? return(*seed);
> >> }
> >
> > So why don't we use that also
> 
> Using a better RNG probably gives better output, even if it deviates
> from the reference.

that is possible but not guranteed, a mathematically better rng might
very well sound worse than a mathematically less random generator.
ultimately if we (mostly mentor) consider this important than we should
do a blind listening test.
If people prefer one that should be used otherwise the simpler generator/
bit identical generator should be used

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

Concerning the gods, I have no means of knowing whether they exist or not
or of what sort they may be, because of the obscurity of the subject, and
the brevity of human life -- Protagoras
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