[Vorbis-dev] sample, windows & vbr

[Monty]

On Thu, Jun 16, 2005 at 05:04:28PM -0700, Mario Antonius wrote:
> Hi, I'm a newbie to audio compression. And I have
> several question about ogg.
> 
> 1. How many bits a vorbis sample take ? 

There is no native bit size.  Internally, the reference encoder and
decoder use floats.

> like the mp3 ? CMIIW

mp3 also has no native word size.  You're proabably just thinking of a
specific encoder.

> 2. How do a decoder recognize how many sample it takes
> in a second ? does it related with the code books ? 

A deocoder simply turns each packets back into a set number of
samples.  The samples/second is set in the header.

> 4. Does vorbis use VBR ?

Vorbis is natively VBR.  ABR/BBR/CBR are implemented out of the VBR algorithms.

> 3. What is function of the Windows ? and what is the
> output of the windows ?

Windows are used in short-time spectral analysis manipulation.  The
simple answer to your question is answered in most undergrad level
signals classes.  The long answer is still the subject pf PHD theses
today. :-)

Monty