There are several data structures used to hold file and bitstream information during vorbisfile decoding.
All the vorbisfile specific data structures are declared in "vorbis/vorbisfile.h" or "vorbis/codec.h".
When using vorbisfile, we usually won't need to know about most of the contents of these data structures, but it may be helpful to understand what they contain.
This structure represents the basic file information. It contains
a pointer to the physical file or bitstream and various information about that bitstream.
This structure contains the file comments. It contains
a pointer to unlimited user comments, information about the number of comments, and a vendor description.