[Vorbis-dev] sample, windows & vbr

[Ralph Giles]

On Thu, Jun 16, 2005 at 05:04:28PM -0700, Mario Antonius wrote:

> 1. How many bits a vorbis sample take ? does the
> sample size 16 bits ? like the mp3 ? CMIIW

Vorbis is natively floating point and can in theory represent well over 
120 dB of dynamic range. Most people feed it 16 bit-per-channel samples
though.

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

Yes. The first packet contains the sample rate and number of channels
for the data the follows.

> 4. Does vorbis use VBR ?

Yes, vorbis is natively VBR. The reference encoder has some support for 
producing "CBR" streams with a more even bitrate.

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

The windows reduce transform and lapping artefacts between coded
blocks. See the paper referenced from the spec for technical details.

Hope that's some help,
 -r