-
Notifications
You must be signed in to change notification settings - Fork 0
/
Final Fantasy II (NES) Music Format.txt
287 lines (222 loc) · 19 KB
/
Final Fantasy II (NES) Music Format.txt
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
FINAL FANTASY II (NES) MUSIC FORMAT
v1.0
By Justin Olbrantz (Quantam)
The permanent home of this specification and others, with the latest updates, is https://github.com/TheRealQuantam/RetroDocs.
The Final Fantasy II sound engine, just like the game itself, sits directly between Final Fantasy and Final Fantasy III, showing a clear intermediate step between predecessor and successor. Although Toshiaki Imai's Final Fantasy engine and the subsequent engines by Hiroshi Nakamura all appear to be distinct codebases, the continuity of features and music encoding is unmistakable, and for the most part music composed in earlier engines can be converted to work on later engines.
The FF2 engine is not entirely abstracted from the NES' Audio Processing Unit hardware. In particular, the FF2 engine allows partial direct access to the ctrl 1 ($4000, $4004, etc.) register. The details of this will be discussed under the corresponding command. For further information see a proper APU programming reference such as https://www.nesdev.org/wiki/APU_registers
Basic Features:
- Compact single-byte notes and rests
+ Staff notation style divisive rhythm system
- 6-octave chromatic scale from C2 (65.4 Hz) to B7 (7457 Hz) for square wave (triangle is 1 octave lower)
- 16 note lengths from whole notes through 64th notes with dots and triplets for some lengths
- Length tie to create arbitrary lengths
- High-precision tempo from 2 to 360 BPM
+ Complex timbre support
Square channels: Duty cycle, channel volume, fade out, volume envelope, and linear period pitch envelope
Triangle channel: Linear period pitch envelope
- 3 channels - square 1 and 2 and triangle - each with separate event sequences
- Single-level unnested loops, with loop break points possible for "play twice" loops
- Has the unusual feature that when a new non-looping track (e.g. a fanfare) is begun the position in the previous track is preserved and is automatically restored when the non-looping track ends.
Major Differences with Final Fantasy:
- 2 additional octaves
- Proper tempo system
- Proper implementation of rests and tied length
+ Multiple envelope changes
- Envelopes no longer required
- Can specify channel volume in addition to volume envelope
- The addition of pitch envelopes
- Support for (short) looping envelopes allowing pitch slide, vibrato, and tremolo
- Introduction of the "odd loop break" mechanic
- Ability to resume the previous track when interrupted with a non-looping track
Some general notes in interpreting this specification:
- All word (16-bit) values in the format are little-endian, with the least-significant byte preceding the most-significant.
- All values are unsigned unless noted otherwise.
- All numbers preceded by $ are hex, and in general unless they represent byte strings or addresses most numbers without $ are in decimal.
- Byte values are generally shown as hex "ab" where "a" is the high nibble and "b" is the low nibble (standard mathematical digit ordering). However, when it is necessary to show bit fields, bytes are shown in binary as "abcd efgh" (mathematical order); in bit fields "-" means that the value of the bit does not matter in the given context.
- Many command lists (e.g. channel data commands) are encoded ambiguously, where 1 value could be interpreted as multiple different commands (e.g. 00 could match 0n). These lists are ordered such that the first matching command is the correct interpretation.
MUSIC FORMAT
Track Header Structure:
+0 word[3]: Channel data addresses in order of square 1, square 2, triangle, or $ffff if none
Note that if a track lacks all 3 channels (the Silence track) it also lacks an end of track command, and consequently maintains silence without triggering reload of the previously playing track.
Channel Data Format
Notes and rests are encoded as single-byte events of the format kL. For notes, k is 0-$b, corresponding to C-B within the current octave, and L is the length the note should play before continuing.
Key number: 0 1 2 3 4 5 6 7 8 9 $a $b
Key: C C# D D# E F F# G G# A A# B
Events of the format dL are tied lengths. These events serve to continue the previous note and extend its length by L time. Unlike in FF3, tied lengths need not immediately follow their notes, and other events may come between them. It is thus possible to make some modifications to the note as it is playing, though some care must be taken with this because not everything is made to work in such a way; e.g. the current envelope positions will only be reset by the start of a new note, NOT by a change to a different envelope.
Finally, rests have the form cL. Unlike in FF1, rests in FF2 behave as expected and properly silence the preceding note.
In all cases L is a length code from the following table:
whole half 4th 8th 16th 32nd 64th
Normal note lengths: 0 2 5 8 $b $d
Dotted note lengths: 1 3 6 9
Triplet note lengths: 4 7 $a $c $e $f
In addition to notes, rests, and tied lengths, the following commands are defined:
e0 tt: Set global tempo to t * 2 BPM. Defaults to 75 (150 BPM). MUST NOT exceed 180 (360 BPM).
e1-ef: Set square wave channel volume to 1 ($e1)-15 ($ef). Defaults to 15. IGNORED if channel has no volume envelope (in this case command $f6 can be used to set the volume by directly setting the ctrl 1 register). This MUST NOT be used on the triangle channel.
f0-f5: Set current octave to 0 ($f0)-5 ($f5). Octave 0 begins at C2 for square wave, while triangle wave is 1 octave lower. Has no default, and MUST be set prior to playing notes.
f6 CC vv ww pp qq: Set timbre and envelopes. Set ctrl 1 to C, set volume envelope address to w:v ($ffff if none) and pitch envelope address to q:p ($ffff if none).
For square wave channels C has the form dd1v xxxx (default of $30):
d: Duty cycle: 12.5% (0), 25% (1), 50% (2), 75% (3)
v: Determines how to interpret x. Must be set if a volume envelope is used.
x: If v is set, the volume for the channel (ignored if a volume envelope is used). If v is clear, volume fades out from 15 to 0 at a rate of 1 volume every x+1 quarter-frames.
For triangle channel C is largely irrelevant and can be left as $80 (the default).
f7 nn: Begin loop and set loop counter to n (> 0)
f8-fb: Begin loop and set loop counter to 2 ($f8)-5 ($fb)
fc xx yy: End loop. Decrement loop counter and if not 0 go to y:x, else end loop and continue.
fd xx yy: Odd loop break. If loop counter is odd (1, 3, etc.) end loop and go to y:x, else continue.
fe xx yy: Go to y:x
ff: End track and on the next frame resume previous track if any
Note that the global nature of the end of track command means that only the first channel's data to reach its end need be explicitly terminated and the other channels will be stopped as well. However, there is a 1 frame delay between track ending and silencing of channels/resuming of the previously playing track. This means that on the terminal frame all channels will be processed even after 1 channel reaches an end of track command; if multiple channels end on exactly the same frame, all such channels must be explicitly terminated to avoid executing invalid data.
Examples
Square wave:
F6 B0 37 BD FF FF: Set timbre and envelopes
1:d = 2: Set duty cycle to 50%
1:v = 1: Set volume (actual volume is ignored because a volume envelope is set)
w:v = $bd37: Set volume envelope address to $bd37
q:p = $ffff: No pitch envelope
E0 32: Set global tempo
n = $32: Set tempo to $32*2=100 BPM
F1: Set current octave to 1 (starting at C3)
0B: Play note
k = 0: C key
L = $b: 16th note
CB: Rest
L = $b: 16th note
E1: Set channel volume to 1
F8: Begin loop and set loop counter to 2
FC 2E A0: Odd loop break
y:x = $a02e: If loop counter is odd (second playthrough) end loop and go to $a02e
FC 0A A0: End loop
y:x = $a00a: Decrement loop counter and if not 0 go to $a00a, else end loop
Triangle:
F6 FF FF FF E4 BE: Set timbre and envelopes
C = $ff: C doesn't really matter for triangle
w:v = $ffff: No volume envelope. Triangle can't use one anyway.
q:p = $bee4: Set pitch envelope address to $bee4
Loop Shenanigans
Overly clever hackers may notice that the fact that the end loop command (as well as odd loop break) specifies an explicit address means the loop need not return to where it began; in fact it need not form a loop at all. Thus the end loop command is essentially an if-then-else statement: decrement the loop counter and if not 0 go to x, else continue; and these commands can be strung together to function like a switch-case structure. This can be abused for a number of purposes, to name a few:
- Loops that repeat a different number of times depending on whether they're in the first or subsequent playthrough of the track. Here the loop simply needs to have different loop counter values set the first time it's run vs. when the track loops.
- Subroutines. A non-looping block of music data can be reached from multiple locations with different loop counter values, and 1 or more end loop commands can be used to return to different locations depending on the value of the loop counter. Though note that using a subroutine in too many places will have a performance impact due to the multiple end loop commands needed.
ENVELOPES
Volume and pitch envelopes have almost identical structure and semantics: an array of byte-sized entries of the form Lv that apply a value v then wait for L frames till the next entry, terminated either by a 0 entry or a loop entry. The only difference is that pitch envelope values are signed and relative while volume values are not. Unlike FF1 and FF3, in FF2 envelopes are identified by address, not index; this makes it easy to add arbitrary new envelopes.
Volume Envelopes
Volume Envelope Format:
00: End of envelope
0o: Loop. Subtract o from current envelope offset in bytes.
Lv: Set envelope volume to v and wait L frames
Volume envelope volume values are independent of the channel volume, and the final volume written to the hardware is floor(channel volume * envelope volume / 15). In the event that a volume envelope does not reach 0 volume, the volume last written to the hardware will be left in place until the next envelope change or rest.
It is interesting to note that while looping volume envelopes are supported, no volume envelopes in FF2 use this feature.
For example:
2F 2E 2D 2C 2B 2A 29 28 27 26 25 24 23 22 21 10 00
2F: Set envelope volume to $f for 2 frames
2E: Set envelope volume to $e for 2 frames
...
10: Set envelope volume to 0 for 1 frame
00: End of envelope
This is a straightforward decay envelope that begins at max volume and fades out at a rate of 1 volume every 2 frames.
1B 1C 1D 1E 1F 1E 1D 1C 1B 1A 19 18 17 26 25 24 23 22 21 10 00
A slightly more complicated envelope that has an attack from $b to $f at a rate of 1 volume/frame, a first decay from $f-6 at a rate of 1 volume/frame, and finally a second decay from 6-0 at 1 volume every 2 frames.
Pitch Envelopes
Pitch Envelope Format:
00: End of envelope
0o: Loop. Subtract o from current envelope offset in bytes.
LLLL nooo: Modify pitch period by n:o (in sign-magnitude format) and wait L frames; if n subtract o (increase pitch), else add o (decrease pitch).
Pitch envelopes directly modify the current wave period and are period-relative, e.g. in a pitch slide (repeating pitch change in 1 direction) the pitch change will accelerate over time when period is decreasing (rising pitch) and decelerate when period is increasing (falling pitch).
1 quirk of the APU is that updates to the high byte of the period retrigger synthesis of the note that is currently playing, which can cause noticeable artifacts. To avoid this the pitch envelope is not allowed to modify the high period byte, and period values are clamped to their nearest $100 boundaries. This has 2 unexpected side effects.
The direct and cumulative modification of the period has the side effect that the base pitch can be shifted due to clamping at the high/low points of the envelope. E.g. if a vibrato envelope has the repeating sequence +2, -2, -2, +2 (+/- 2) but the current period is $1ff and +2 would cause a boundary crossing, the result will be $1ff + 2 = $1ff, and then $1ff - 4 + 2 = $1fd, NOT $1ff; the center frequency has shifted.
Worse is that pitch slides will abruptly stop at the nearest $100 boundary. Working around these jarring stops is left as an exercise to the composer.
Examples
F0 49 41 02
F0: Set period offset to +0 for $f frames
49: Set period offset to -1 for 4 frames
41: Set period offset to +1 for 4 frames
02: Loop back 2 entries
This is a vibrato envelope with a delay of 15 frames, a depth (peak to peak) of 1 period unit, and a period of 8 frames (7.5 Hz).
49 42 4A 42 4A 42 4B 44 4C 02
This is a vibrato envelope with period of 8 (7.5 Hz) but a depth that grows from 1 to 8 over 28 frames (~0.5 sec).
11 01
A trivial falling pitch slide that increases period at a rate of 1/frame. As previously mentioned, the fall in pitch will decelerate over time; e.g. at A440 pitch will decrease at a rate of 6.8 cents/frame, while at A880 pitch will decrease at a rate of 3.4 cents/frame. Except for 1 little detail: the period register value for A440 is $fd, and A880 is $1fa, just short of a $100 boundary; thus in reality this envelope will have little effect on an A440 or A880 note.
SOUND EFFECTS
As with FF1, FF2 does not have a dedicated mechanism or format for playing sound effects, and most sound effects are played ad hoc. 5 sound effects, however, are actually non-looping music tracks, as can be seen in the track table.
ADDITIONAL TABLES
All addresses are in the CPU address space, and all music data is in bank $d at address $8000. The file offset = addr + 0x2c010.
Note/Rest Length Table in Ticks:
0: Whole (96)
1: Dotted half (72)
2: Half (48)
3: Dotted 4th (36)
4: Triplet half (32)
5: 4th (24)
6: Dotted 8th (18)
7: Triplet 4th (16)
8: 8th (12)
9: Dotted 16th (9)
a: Triplet 8th (8)
b: 16th (6)
c: Triplet 16th (4)
d: 32nd (3)
e: Triplet 32nd (2)
f: Triplet 64th (1)
Track Table
Table of track header addresses: $9e0d ($35e1d)
The Main Theme is assigned 3 different track numbers. It's possible these may be used in different areas, but I don't know where.
Track Name HdrA Sq1A Sq1FO Sq2A Sq2FO TriA TriFO
0 (0) Silence 9e4b: ffff ffff ffff
1 (1) Prelude 9e51: 9e57 (35e67) 9f57 (35f67) ffff
2 (2) Sound Effect 1 9f62: 9f68 (35f78) 9f7c (35f8c) ffff
3 (3) Chocobo Theme 9f87: 9f8d (35f9d) 9fcc (35fdc) 9fe1 (35ff1)
4 (4) Main Theme 9ff2: 9ff8 (36008) a04b (3605b) a056 (36066)
5 (5) Main Theme 9ff2: 9ff8 (36008) a04b (3605b) a056 (36066)
6 (6) Main Theme 9ff2: 9ff8 (36008) a04b (3605b) a056 (36066)
7 (7) Fanfare a167: a16d (3617d) a197 (361a7) a1b5 (361c5)
8 (8) Sound Effect 2 a1c4: a1ca (361da) a1eb (361fb) ffff
9 (9) Sound Effect 3 a20d: a213 (36223) a234 (36244) ffff
10 (a) Join the Party! a255: a25b (3626b) a279 (36289) a299 (362a9)
11 (b) Castle Pandemonium a2a0: a2a6 (362b6) a303 (36313) a3e8 (363f8)
12 (c) Ancient Castle a465: a46b (3647b) a4c9 (364d9) a564 (36574)
13 (d) Tower of the Magi a5eb: a5f1 (36601) a6a0 (366b0) a734 (36744)
14 (e) Imperial Army Theme a7ba: a7c0 (367d0) a85d (3686d) a8da (368ea)
15 (f) Dungeon a99b: a9a1 (369b1) aa9a (36aaa) aada (36aea)
16 (10) Town ab0b: ab11 (36b21) ab9b (36bab) ac25 (36c35)
17 (11) The Rebel Army ac5a: ac60 (36c70) acc7 (36cd7) ad0b (36d1b)
18 (12) Battle Theme ad5a: ad60 (36d70) ae5e (36e6e) af53 (36f63)
19 (13) Battle Theme 2 b030: b036 (37046) b1c6 (371d6) b3a7 (373b7)
20 (14) Sound Effect 4 b510: b516 (37526) b521 (37531) ffff
21 (15) Victory b52a: b530 (37540) b596 (375a6) b5f5 (37605)
22 (16) Game Over b64a: b650 (37660) b678 (37688) b6c4 (376d4)
23 (17) The Princess's Seduction b6d5: b6db (376eb) b703 (37713) b70f (3771f)
24 (18) Revival b74d: b753 (37763) b772 (37782) b77e (3778e)
25 (19) Reunion b785: b78b (3779b) b7b1 (377c1) b816 (37826)
26 (1a) Escape! b826: b82c (3783c) b860 (37870) b874 (37884)
27 (1b) Waltz b8a0: b8a6 (378b6) b8e0 (378f0) b93f (3794f)
28 (1c) The Emperor's Rebirth b980: b986 (37996) b9b0 (379c0) b9cc (379dc)
29 (1d) Finale b9e1: b9e7 (379f7) bb3d (37b4d) bc78 (37c88)
30 (1e) Sound Effect 5 bce2: bce8 (37cf8) ffff ffff
The code that accesses the track table:
986E LDA $9E0D,X
9871 STA $C8
9873 LDA $9E0E,X
9876 STA $C9
Volume Envelopes
In an attempt to be more intuitive, pairs show volume on the left side and length on the right side. Terminal 00 bytes are not shown, but can be assumed as no volume envelopes loop.
bd04 (37d14): 15:2 14:2 13:2 12:2 11:2 10:2 9:2 8:2 7:2 6:2 5:2 4:2 3:2 2:2 1:2 0:1
bd15 (37d25): 15:2 14:2 13:2 12:2 11:2 10:2 9:2 8:2 7:3 6:4 5:4 4:4 3:4 2:4 1:4 0:1
bd26 (37d36): 15:2 14:2 13:2 12:2 11:2 10:2 9:2 8:6 7:7 6:8 5:8 4:9 3:11 2:13 1:15 0:1
bd37 (37d47): 15:2 13:2 11:2 9:2 7:2 5:5 4:9 3:11 2:13 1:15 0:1
bd43 (37d53): 5:1 6:1 7:1 8:1 9:2 10:2 11:2 12:2 13:2 15:2 13:2 15:2 13:2 15:2 13:2 15:2 13:2 15:2 13:2 15:2 13:2 15:2 13:2 15:2 13:2 12:4 11:4 10:4 9:5 8:5 7:5 6:6 5:6 4:6 3:7 2:7 1:7 0:1
bd6a (37d7a): 7:1 9:1 11:1 13:1 15:2 14:2 15:2 14:2 15:2 14:2 15:2 14:2 15:2 13:2 11:2 14:2 12:2 10:2 13:2 11:2 9:2 12:2 10:2 8:2 11:2 9:2 7:2 10:2 8:2 6:2 9:2 7:2 5:2 8:2 6:2 4:2 7:2 5:2 3:2 6:2 4:2 2:2 5:2 3:2 1:2 0:1
bd99 (37da9): 6:1 15:1 8:1 15:1 10:1 15:1 11:1 15:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 15:1 13:1 14:1 12:1 11:3 9:3 7:3 5:3 3:3 1:3 0:1
bdd2 (37de2): 15:1 6:1 8:1 9:1 10:1 11:1 12:1 13:1 14:1 15:2 14:2 13:2 14:2 15:2 14:2 13:2 14:2 15:2 14:2 13:2 14:2 15:2 14:2 13:2 14:2 15:2 14:2 13:2 14:2 15:2 14:2 13:2 14:2 15:2 14:2 13:2 14:2 15:2 14:2 11:3 9:3 7:3 5:3 3:3 1:3 0:1
be66 (37e76): 6:1 3:1 6:1 8:1 10:1 12:1 14:1 15:2 13:1 14:1 12:1 15:3 13:1 14:1 12:1 15:15 15:12 14:2 13:2 12:2 11:2 10:2 9:2 8:2 7:2 6:2 5:2 4:2 3:2 2:2 1:2 0:1
be87 (37e97): 3:2 5:2 7:2 9:2 11:2 13:2 15:3 12:3 15:3 12:3 15:3 12:3 15:3 11:3 14:3 10:3 13:3 9:3 12:3 8:3 11:3 7:3 10:3 6:3 9:3 5:3 8:3 4:3 7:3 3:3 6:3 2:3 5:3 1:3 4:3 3:3 2:3 1:3 0:1
beaf (37ebf): 11:1 12:1 13:1 14:1 15:1 14:1 13:1 12:1 11:1 10:1 9:1 8:1 7:1 6:2 5:2 4:2 3:2 2:2 1:2 0:1
Pitch Envelopes
Pairs show period offset on the left side and length on the right. Loops are indicated with structures like -2->1 which show the relative byte offset on the left side and the new absolute offset on the right. Terminal 00 bytes are not shown for non-looping envelopes.
bec4 (37ed4): +0:4 +1:15
bec7 (37ed7): +0:15 -1:4 +1:4 -2->1
becb (37edb): +0:7 -1:3 +2:3 -2:3 +2:3 -2:3 +2:3 -3:3 +4:3 -4:3 -2->8
bedd (37eed): -1:4 +1:4 -2->0
bee0 (37ef0): -1:15 -1:4 +1:4 -2->1
bee4 (37ef4): -1:4 +2:4 -2:4 +2:4 -2:4 +2:4 -3:4 +4:4 -4:4 -2->7
bef9 (37f09): -2:15
befb (37f0b): +1:1 -1->0
befd (37f0d): +3:1 +1:1 -1->1