Castlevania Music Format

Castlevania Music Format v1.0
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
by Sliver X

Notes
~~~~~
First nibble denotes pitch, second denotes time

First nibble: Range: 0 - B ("C" to "B")
{C C# D D# E F F# G G# A A# B}
{0 1  2 3  4 5 6  7 8  9 A  B} 

Second nibble: 0 - F (0 is fastest, F is slowest)
CX is a rest.

Octaves
~~~~~~~

E0 - E4 (Highest octave to lowest)

E0 is high pitched, E1 is lower, E2 is very low, E3 is barely audiable,
E4 is so low it's silent. (The silent values seem to be used for "drum solos", i.e.
stretches of noise: see Noise Data below for more info)
Remains silent until E8, which is highest again.

Instruments
~~~~~~~~~~~
00 - FF

Instrument sets. x0 is harshest duty cycle, while xF is smoothest. Each range of 16
employs different ASDR techniques (Fade, attack, etc).

An instrument change *must* be preceded by a tempo change (See below), otherwise you'll just
make it a note.

Tempo
~~~~~
D1 - DF (Fastest to slowest) 

Controls the entire speed of the following notes until a new D* is encountred.
D1 is so fast it's retarded, while DF is really slow. Note that D0 is *EXTREMELY* slow.

Noise Data
~~~~~~~~~~
Range: E9 - EA 

This is used for percussion effects. These can be located in any channel's data. The way it
works is that it follows a note definition to determine its speed. So B0E9 would be a very
fast hit, and BFE9 would be a hit followed by a long pause. If you do not precede a noise
byte with a note value, things will get *VERY* badly messed up. It should also be noted that
that the "drum" will sound at the same time as the preceding note. If you're simply wanting
a stretch of percussion, set the octave to E4 beforehand.

E9 sounds like a snare.
EA sounds like a closed high-hat.

Repeating
~~~~~~~~~

FEXXXXXX

FE followed by three bytes is a repeat control. Second byte is the number of times to repeat (FF is infinity), and the third
and fourth are the pointer to loop to. Note that this must come after a note (As opposed to a noise "drum" sound),
otherwise the drums won't repeat. This would mean you can't put a drum effect at the very end of a song.

Figure 1: Triangle/Noise Repeat
*******************************
(FEFF)B59D

Calculating:
~~~~~~~~~~~~

Pointer to Address:
 
 B59D

 Now take the pointer and swap the bytes:

 9DB5

 Now subtract $8000:

 1DB5

 Now add $10:

 1DC5 (Address)

Address to Pointer:

 1DC5

 1DB5

 9DB5

 B59D (Pointer)


MASTER POINTERS
~~~~~~~~~~~~~~~

This is the list of pointers that tells the game where the start of each channel is; these can
be manipulated to move music data elsewhere in ROM, if you can find the space. 

The format is six bytes for Square 1, Square 2, and Triangle, (Two byte pointer per),
then a seperator byte that should not be messed with...

Music
#####

Track 1		Track 2		Track 3		Track 4		Track 5		Track 6 
--------	--------	--------	--------	--------	--------
Sq1: 825	Sq1: 82E	Sq1: 837	Sq1: 840	Sq1: 849	Sq1: 852
Sq2: 828	Sq2: 831	Sq2: 83A	Sq2: 843	Sq2: 84C	Sq2: 855
Tri: 82B	Tri: 834	Tri: 83D	Tri: 846	Tri: 84F	Tri: 858

Track 7		Track 8		Track 9		Track 10	Track 11	Track 12 
--------	--------	--------	--------	--------	--------
Sq1: 85B	Sq1: 864	Sq1: 86D	Sq1: 876	Sq1: 87F	Sq1: 888
Sq2: 85E	Sq2: 867	Sq2: 870	Sq2: 879	Sq2: 882	Sq2: 88B
Tri: 861	Tri: 86A	Tri: 873	Tri: 87C	Tri: 885	Tri: 88E

Track 13	Track 14	Track 15
--------	--------	--------
Sq1: 891	Sq1: 89A	Sq1: 8A3
Sq2: 894	Sq2: 89D	Sq2: 8A6
Tri: 897	Tri: 8A0	Tri: 8A9


Sound effect indexes seem to follow, but are beyond the scope of this document.