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

Måns Rullgård mans
Mon Sep 20 22:40:09 CEST 2010


Michael Niedermayer <michaelni at gmx.at> writes:

> 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.

I meant better in the context of this application, not necessarily in
any mathematical sense.

-- 
M?ns Rullg?rd
mans at mansr.com



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