[vorbis] Date: Wed, 10 Mar 2004 16:15:12 +0530

[Leena]

Hello !!

   While reading I am facing lot of problems . Doing reserve enginnering
without any document is
really putting in trouble . ( that is not the case in ac3 , mp3 ) .

 The problems are ---->

1. How physcoacoustic  model is generated . I was reading noise masking .
   I have understood that FFT of 2048 samples is used for finding tone
masking .
    And MDCT of same samples is used for noise masking .

    Now while caluculating noise masking , logmdct input is used . And
function
     bark_noise_hybridmp is called . In that function some mathematical
computation is done and
     noise is calculate . ( noise[i] = R - offset )

     Can anyone explain me what is the funda behind it .

<p>2.  NOw about overlap and add .
     I know very well how overlap add solves the aliasing problem afer IMDCT
. I have checked it
     matematically .

     Now here , when there is overlapping of unequal size window , ie
short - long - short .  the window
     shape is modified . I am clear with that ...But I am not getting the
original data after IMDCT and overlap add .
     Can anyone explain me this ..?

<p><p>   Thanks & reagrds

   Leena

<p>--- >8 ----
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