[FFmpeg-soc] [soc]: r3046 - in aac: aac.c aac.h

[Robert Swain]

2008/8/7 Reimar Doeffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>:
> On Wed, Aug 06, 2008 at 09:21:32PM -0400, Justin Ruggles wrote:
>> superdump wrote:
>> > Author: superdump
>> > Date: Wed Aug  6 12:00:44 2008
>> > New Revision: 3046
>> >
>> > Log:
>> > Use a simple LCG as recommended in libavutil/lfg.* rather than Mersenne Twister
>> > as such noise is good enough (sounds the same to my ears on a 1 second sample)
>> > and calculation is faster
>>
>> Why not add that to libavutil as well?  I would like to use it for AC-3.

It could be added with little difficulty. Should it go into
libavutil/lcg.(c|h)? The code will be _very_ short. :)

> In that case though I think it would be nice if there was some additional information
> on the particular numbers used, and also mentioning that the last bit is always alternating
> for this kind of generator (so if possible, only the upper bits should be used).
> Believing some random guy on the internet: http://random.mat.sbg.ac.at/~charly/server/node3.html
> 2147001325*a+715136305
> at least has some statistics, I could not find any for the current numbers on a quick search.

A quick search for 'LCG 1013904223' throws a number of results. This
LCG is apparently from Numerical Recipes. I should probably >>16 the
values returned by lcg_random().

Rob