[vorbis-dev] Questions about window sizes

[stoffke at directbox.com]

Hello,
I have a few questions about the block size in ogg vorbis
1. The allowed blocksizes are powers of two between 64 and 8192 Samples.
As I understood , there are  fixed sizes for long and short blocks . 
The encoder can pick any allowed value for long blocks and onother value, that must 
be smaller or equal to the first one, for short blocks.
On which base does the encoder choose the size for long/short blocks ?
Why are there so many possible blocksizes - would it be necessary
to analyze the entire track to find the out, which sizes fits best ?

2. How does the encoder decide , whether to use short or long blocks during encoding ?
In earlier versions, it was done "by 4 parallel bandpass filters that detect energy surges",
but Monty said it will be changed. 
(http://www.xiph.org/archives/vorbis-dev/200109/0054.html )

Thanks
Stoffke

<p>--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.