[vorbis] intro to compressed audio tutorial

[fungus]

Graham Mitchell wrote:
>
>http://cs.leander.isd.tenet.edu/~mitchell/vorbis_intro.html
>

<p>One correction: In the "Why?" paragraph it says the loudest
volume is 65535. It isn't, it's 32767 - the numbers are
signed so they go from -32768 to +32767.

<p>"I don't know really know the difference between ABR and VBR,
  which one Vorbis uses by default, and which is better.
  Corrections welcomed."

VBR simply uses as many bits as are needed for the quality
requirements without considering the resulting bitrate.

Average bit rate (ABR) says that the bitrate over an
interval of time must be within certain limits. Individual
data blocks may have more or less than 128kbits, but the
average block size must be 128kbits. This is needed for
streaming where you have bandwidth constraints. You can
increase overall quality by passing surplus bits from
one block to another, so long as you maintain the average
rate then the buffering in the player will smooth things
out.

<p><p>
-- 
<\___/>
/ O O \
\_____/  FTB.

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