Audioseq

Audioseq contains data for playing the game's sequenced music. The sequenced music in the Zelda 64 games follows a MIDI type format which is a slightly updated version of that used in earlier games like Super Mario 64.

Moving Audioseq

To move the Audioseq file to another location in ROM, you will need to correct its entry in the file table, update the assembly code used to load sequences from the file, and update the CRC. This can be found at 0xB5A4AC (Debug ROM) and looks like:

3C05 xxxx 24A5 yyyy

In MIPS assembly:

LUI       $A1,xxxx
ADDIU     $A1,$A1,yyyy

• x = upper half of address
• y = lower half of address

Sequence Pointer Table

code (File)
Sequence Table List

Version	Offset	VRom		VRam
Debug	1386A0	00BCC6A0	00BCCD90	80155500	80155BF0
NTSC 1.0	102AD0	00B89AD0	00B8A1C0	80113B70	80114260
NTSC 1.1	102C90	00B89C90	00B8A380	80113D30	80114420
NTSC 1.2	102B40	00B89B40	00B8A230	80114220	80114910
PAL 1.0	100290	00B89290	00B89980	80111970	80112060
PAL 1.1	1002D0	00B892D0	00B899C0	801119B0	801120A0
JP GC	1021F0	00B881F0	00B888E0	801130D0	801137C0
JP MQ	1021D0	00B881D0	00B888C0	801130B0	801137A0
USA GC	1021D0	00B881D0	00B888C0	801130B0	801137A0
USA MQ	1021B0	00B881B0	00B888A0	80113090	80113780
PAL GC	0FF9C0	00B879C0	00B880B0	801108C0	80110FB0
PAL MQ	0FF9A0	00B879A0	00B88090	801108A0	80110F90
JP Collection	1021D0	00B881D0	00B888C0	801130B0	801137A0

The sequence pointer table begins with an 0x10 byte header:

/* 0x00 */ short NumberOfSequences = 0x6E;
/* 0x04 */ int AudioSeq_StartAddress; //ram only
/* 0x08-0x0F is padded to 0 */

Following that is a record for each sequence in the table:

xxxxxxxx yyyyyyyy uuaa 0000 00000000

• x = Pointer to the start of the sequence in the sequenced music file. In rom, this value is an offset relative to the start of the file, while in ram, this value will be converted into the VRom address that the sequence is located at
• y = Length of the sequence, in bytes.
• u = Unknown. Value set to 0x02
• a = Sequence Type, affects memory allocation. 0x00 is Hyrule Field, 0x01 is fanfares, 0x02 is BGM

Format

There are generally three different parts to the sequences:

Sequence Header
This is the part of the sequence that controls things such as master volume, tempo and loop settings.

Channel Header
Controls volume, pan, etc. and points to music data to be played back on each channel.

Music Data
Contains the data for which notes should be played, their velocity, length, etc.

From here, all numbers will be given in hexadecimal unless stated otherwise.

Sequence Header Commands

Command	Description
D3 xx	Seems to be something to do with the sequence type or format; for Super Mario 64, xx is usually 80, for Zelda 64, xx is usually 20.
D5 xx	Unknown. xx usually takes the value of 32. For sequences that don't play any music xx is 46.
D7 xxxx	Enables channels given by xxxx (boolean, each channel is one bit).
9x yyyy	Points to a channel header offset. x is the channel number (0 - F) and yyyy is the offset of that channel's header relative to the start of the sequence file.
DB xx	Master volume control, xx is the volume.
DD xx	Tempo control, xx is the tempo value in beats per minute.
CC yyxx	Unknown. yy starts at zero and increases each time the command appears, xx is (always?) 73.
FD xx / FD yyyy	Timestamp (number of 'ticks' to wait before the next command is read, relative to tempo), variable length. If xx goes above 7F, add 8000 to it to get yyyy.
FB xxxx	Offset to loop from, xxxx is the offset relative to the start of the sequence file.
D6 xxxx	Disables channels given by xxxx.
FF	Marks the end of the sequence header.

Some sequences have the following data after the first four bytes of their sequence header. Its purpose is currently unknown but it may be to do with continuing playback mid-sequence after returning to the area from a house/shop:
D7FFFF 8776CCFF7786F3 vv F2 ww C801F3 xx [C801FA yyyy] FB zzzz

v, w and x are unknowns, y and z seem to be pointers to 9x commands for different parts of the sequence within the sequence header. The part in square brackets is repeated in some sequences.

Channel Header Commands

Command	Purpose	Variables
C4	Initialises the channel for music playback
8x yyyy	Points to music data to be played on the current channel	x is 'note layer' to be used (8 - B). A maximum of four note layers can be loaded per channel. y is the offset of the music data to be played, relative to the start of the sequence file.
DF xx (yy)	Channel volume	x is the volume value y is a timestamp used between control changes (when the volume is changing constantly)
DD xx	Channel pan	x is the pan amount, 00 = hard left, 3F = centre, 7F = hard right
E9 xx	Priority. Unknown how it is used	x = ?
D4 xx	Effects level (echo)	x is the effect amount
D8 xx (yy)	Vibrato	x Vibrato amount. Higher values can produce odd sounds. y is a timestamp used between control changes
D3 xx (yy)	Pitch bend	x Pitch bend amount, signed. y is a timestamp used between control changes
C2 xx	Transposition	x is the number of semitones to transpose by. Signed value
C1 xx	Sets the instrument number	x instrument number to be used for the current channel
FD xx / FD yyyy	Timestamp (see sequence header commands).
FF	Marks the end of the channel header.

Music Data

Things get a little more complicated here.

Command	Format	Description	Values	Notes
nn (0x00 to 0x3F)	tt(tt)vvgg	Play note	n = Note value t = Variable length timestamp v = Note velocity g = Gate time
nn (0x40 to 0x7F)	tt(tt) vv		n = Note value + 40 t = Variable length timestamp v = Note velocity	Gate time is the same as was used for the previous play note command.
nn (0x80 to 0xBF)	vv gg		n = Note value + 80 v = Note velocity g = Gate time	Timestamp is the same as was used for the previous play note command.
C0	xx, or yyyy	Timestamp / rest	x or y is the variable length timestamp value	Used when no music needs to be played for a set amount of time
FC	xxxx	Jump to offset	x is offset relative to the start of the sequence file to jump to	Plays the data from there until it reaches the next FF command
FF		Terminator		Marks the end of the current music data.

Note: It seems that some of the channel header commands are valid for use in the music data but the only one that's really useful is the C2 command (transposition).

Differences with the Super Mario 64 format

In Super Mario 64, the 8x yyyy command appears as:

9x yyyy

Where x is the 'note layer' to use (0 - 3) and yyyy is the offset to load music data from relative to the start of the sequence file.
Super Mario 64 does not use the E9 (priority) command and does not seem to be compatible with the way Zelda 64 does control changes. There may be other differences but this has not been looked into fully as of yet.

Tips for converting from MIDI

Zelda note value = MIDI note value - 0x15
Zelda timestamp = (MIDI timestamp/0x80)*0x18

Instrument Sets

There is no master instrument index in Zelda 64 as there is for MIDI sequences, instead there are different instrument sets that contain the instruments needed to play each sequence. The instrument set a sequence uses is not defined in the sequence itself but is defined externally. The lookup table for this data is retrieved in a rather unusual way:

In the Debug Rom for example, address BCC4E0 acts as the start address to the table. In order to reach the instrument set record, the game reads the halfword at BCC4E0 + (SequenceId * 2), then adds that to BCC4E0 to reach the appropriate record. Fortunately, this calculation can be simplified as being Table Start (BCC4E0 for debug) + DD + (SequenceId * 2) for all but sequence 0, where you'll have to subtract the result by 1.

nnii*

• n is number of Instrument Sets within the record
• i is the Instrument Set number for the Sequence

code (File)
Instrument Sets

Version	Offset	VRom		VRam
Debug	1384E0	00BCC4E0	?	80155340	?
NTSC 1.0	102910	00B89910	?	801139B0	?

Here's a list of which sequences use which instrument sets:

OoT instrument sets list

Instrument Set Number	Purpose	Dependent Sequences
0x00	Ocarina songs	0x44 0x45 0x46 0x47 0x48 0x49
0x01	Actor Sounds	none
0x02	Nature Sounds	0x01
0x03	Hyrule Field	0x02 0x03 0x04 0x05 0x06 0x07 0x08 0x09 0x0A 0x0B 0x0C 0x0D 0x0E 0x0F 0x10 0x11 0x12 0x13 0x14 0x15 0x16 0x17 0x19 0x1A 0x1B 0x1F 0x21 0x23 0x2B 0x2D 0x31 0x32 0x38 0x3B 0x43 0x4A 0x51 0x52 0x53 0x54 0x62 0x6C
0x04	Deku Tree	0x1C
0x05	Market	0x1D 0x3E
0x06	Title Screen	0x1E
0x07	Jabu Jabu's Belly	0x26
0x08	Kakariko Village (guitar)	0x27 0x4C
0x09	Fairy Fountain	0x28 0x29 0x3A 0x3D 0x4B 0x4F 0x57 0x66 0x6A
0x0A	Fire Temple	0x2A
0x0B	Dodongo's Cavern	0x18
0x0C	Forest Temple	0x2C
0x0D	Lon Lon Ranch	0x2F
0x0E	Goron City	0x30
0x0F	Kokiri Forest	0x3C
0x10	Spirit Temple	0x3F
0x11	Horse Race	0x40 0x41 0x42
0x12	Warp songs (ocarina songs 2)	0x25 0x33 0x34 0x35 0x36 0x37 0x59
0x13	Goddess Cutscene	0x4D 0x56 0x5D
0x14	Shooting Gallery	0x4E
0x15	Zora's Domain	0x50
0x16	Shop	0x55
0x17	Ice Cavern	0x58
0x18	Shadow Temple	0x5B
0x19	Water Temple	0x5C
0x1A	Blank?	none
0x1B	Gerudo Valley	0x5F
0x1C	Lakeside Laboratory	0x60
0x1D	Kotake and Koume's Theme	0x61
0x1E	Ganon's Castle (organ)	0x2E
0x1F	Inside Ganon's Castle	0x63
0x20	Ganondorf Battle/Boss Battle 2	0x5E 0x64 0x65 0x6B
0x21	Ending sequence 1	0x67 0x69
0x22	Ending sequence 2	0x68
0x23	Game Over/Fanfares	0x20 0x22 0x24 0x39
0x24	Owl	0x5A

Legacy Credits

messiaen, DeathBasket - Sequence format
messiaen - pointer table format
DeathBasket - Instrument set lists for OoT and MM
DeathBasket - Writing this