Vorbis dev - Oct 2009 - How to get the actual bitrate?

Dear all:
  I'm a developer in china, and i really want to know how to calculate a ogg
audio file's bitrate and then i can get the duration by file size.
  thanks very much for your answer.
                                                   Best wishes. 
                                                   Aaron Jie.
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??? escreveu:
> Dear all:
>   I'm a developer in china, and i really want to know how to calculate
a ogg audio file's bitrate and then i can get the duration by file size.
>   thanks very much for your answer.
See, most of ogg vorbis files have variable bitrate, so the way to
calculate its mean bitrate -- the only significant bitrate when speaking
of the whole stream -- is size/duration, what imply you must know the
duration beforehand.

I'm afraid you can't know the duration of the stream by just looking at
the file size, since even libvorbis must be able to seek through the
stream to be able to determine it's duration.

-- 
Lucas Clemente Vella
lvella at gmail.com