Return the Ogg page with the absolute index index,
independent from the logical structure of this stream or if the
index parameter is -1, the next Ogg page is returned.
This method should only be used by implementations of LogicalOggStream
to access the raw pages.
Sets this stream's (and its logical stream's) position to the granule
position. The next packet read from any logical stream will be the
first packet beginning on the first page with a granule position higher
than the argument.
At the moment, this method only works correctly for Ogg files with
a single logical Vorbis stream, and due to the different interpretations
of the granule position, depending on mixed content, this method will
never be able to work for mixed streams. Chained and interleaved streams are
also not yet supported. Actually, this method is only a hack to support
seeking from JMF, but may of course be abused otherwise too :)