[vorbis] hello !!

Leena leena.padgaonkar at patni.com
Sun Feb 22 23:03:36 PST 2004



    Hi !!

<p>    I am just now reading Vorbis I specifications .

   I ahve some quries in that regading overlap add and sqaure polar mapping
.

   I am writting this mail with the hope that ,some one will resolve my
quries.

<p>   1. After IMDCT , to remove the aliasing , we do overlap and add . For
that the
      window should have following properties ------------->
        hk = h2n-1-k and
        (hk* hk) + (hk+n * hk+n)  = 1 .    when 2n is the input block size
for MDCT in encoder .

     THis is very imp requirement of overlap add in MDCT .

<p>     What about overlap add in Vorbis ..? What type of winodw  criterias are
there ..? What is
     the winodw function .?

<p> 2.    I am very clear about how the aliasing goes in overlap add in equal
sized winodw . But
     I am not getting how it is canelled in large winodw following short
window ..?
     Can any one tell me taht mathematically..?

<p> 3.   In suare polar mapping how the spatial information is split in point
and diffuse images ..?

<p><p>   Thanks & regards

<p>  Leena

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