Ogg Vorbis File Format

Offset   Length   Contents
[ 0      4 bytes  "OggS"
  4      1 byte   Stream structure version (0x00)
  5      1 byte   Packet flag:
                    bit 0:  true if page continued
                    bit 1:  true if first page
                    bit 2:  true if last page
                    bit 3..7: reserved
  6      8 bytes  The end pcm sample position (64bit integer)
 14      4 bytes  Stream serial number
 18      4 bytes  Page number
 22      4 bytes  Check sum
 26      1 byte   Number of segments(s)
 27     (s)bytes  Sengment table
 27+(s) (b)bytes  Body (b := header[27] + header[27+1] + ... + header[27+s-1])
]*