opus - Apr 2011 - Inside the psydecay_init function

Good Morning;

Fo this portion of code in the psydecay_init( ) of CELT (psy.c)?:

decayR[i]=Q15ONE*power(0.1f,deriv)?? /commented: decay corresponding to -10 
dB/Bark.

decayL[i]=Q15ONE*power(0.0031623f,deriv)?? /commented: decay corresponding to 
-25 dB/Bark.


Why 0.1 (or 0.0031623)?is being raised to the power of deriv? what is the 
meaning of this? why 0.1(or 0.0031623) ?not other number? is it?? related?to 
(-10, -25 respectively) how?we get it?!

Why Q15ONE (which is either 32767 or 1.0f, as I have observed it in the code) is
being multiplyied by the term also?

Thank you?for your attention,

Osama.
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> Why 0.1 (or 0.0031623) is being raised to the power of deriv? what is
> the meaning of this? why 0.1(or 0.0031623) not other number? is it
> related to (-10, -25 respectively) how we get it?!
-10 dB in a linear scale is 10^(-10/10) = 0.1
-25 dB in a linear scale is 10^(-25/10) = 0.0031623
> Why Q15ONE (which is either 32767 or 1.0f, as I have observed it in the
> code) is being multiplyied by the term also?
Presumably to give it the proper scaling for fixed-point.

However, this entire file, including this function, has been removed 
from the current version of the code.