Music File Format
structure of a .mus file
|Offset00:||BYTE the value 0x00 (i think this indicates that this is a .mus file, picture files are identified by 02)|
|Offset01:||BYTE the value 0x01 (i believe this is the number of music sequences in the file. there is a similar byte like this in a .pic file, indicating the number of pictures in the file)|
|Offset02:||WORD the length of the musical sequence. This value will be a multiple of 2.|
|Offset04:||music data, with (note,length) pairs until the end of the file|
As far as i've been able to tell, the value 0x08 is C-4 on the midi scale, and increases/decreases in half-steps. 0xFF is a pause. i'm not sure what the lengths are measured in, but 0x20 is a pretty decent quarter note.