The 'File type' frame indicates which type of audio this tag defines.
The following types and refinements are defined:
MIME MIME type follows
MPG MPEG Audio
/1 MPEG 1/2 layer I
/2 MPEG 1/2 layer II
/3 MPEG 1/2 layer III
/2.5 MPEG 2.5
/AAC Advanced audio compression
VQF Transform-domain Weighted Interleave Vector Quantisation
PCM Pulse Code Modulated audio
but other types may be used, but not for these types though. This is
used in a similar way to the predefined types in the "TMED"
frame,
but without parentheses. If this frame is not present audio type is
assumed to be "MPG".
@author Eric Farng
@version $Revision: 1.4 $