BMS (File Format)

File Format

BMS files are Binary Music Sequences that store commands for the audio engine to play notes, similar to the MIDI file format.

Data

BMS files contain raw instructions for the audio engine. There are no headers or filesize checks. Each instruction (OpCode) stands for its own function in the engine. The following table lists all JAudio2 OpCodes that have functions in SMG2:

OpCode	Function (SMG/SMG2)	Usage	Example	Description
00 01 02 ... 7D 7E 7F		{OpCode[1]} {Voice[1]} {Velocity[1]} OpCode: one byte with range 0x00 through 0x7F. 0x00 = C-1, 0x60 = C4 (middle C), 0x7F = G9. Voice: one byte with range 0x01 through 0x07 (needs testing/verification). Each Voice can only hold one Note. Velocity: one byte with range 0x00 through 0x7F. 0x00 = 0, 0x7F = 127. If the Voice is not 1 - 7, the game will treat this note as a Midi Gate note, and will expect a 4th value that is one or more bytes with range 0x00 through 0xFF. If the leading byte is 0x80 (bit 7 = 1) or greater, another following byte will be taken into account. It is unknown what effects this has on the output	64 02 68 64: Key E4 02: Voice 2 68: Velocity 104	Starts playing a Note with the previously defined Instrument (see E1, E2 and E3).
80	Unknown. Seems to do nothing based on the code...
81 ... 87		{OpCode[1]} OpCode: one byte with range 0x81 through 0x87. 0x81 = Close Voice 1, 0x87 = Close Voice 7.		Stops playing a Note.
88 ... 8F	Unknown
90 ... 9F	Unknown
A0	NULL
A1	NULL
A2	NULL
A3	NULL
A4	NULL
A5	NULL
A6	NULL
A7	NULL
A8	NULL
A9	NULL
AA	NULL
AB	NULL
AC	NULL
AD	NULL
AE	NULL
AF	NULL
B0	Extended Opcode Indicator
B1	JASSeqParser::cmdNoteOn
B2	JASSeqParser::cmdNoteOff
B3	JASSeqParser::cmdNote
B4	JASSeqParser::cmdSetLastNote
B5	NULL
B6	NULL
B7	NULL
B8	JASSeqParser::cmdParamE
B9	JASSeqParser::cmdParamI
BA	JASSeqParser::cmdParamEI
BB	JASSeqParser::cmdParamII
BC	NULL
BD	NULL
BE	NULL
BF	NULL
C0	NULL
C1	JASSeqParser::cmdOpenTrack	{OpCode[1]} {TrackNumber[1]} {Pointer[3]} OpCode: one byte, C1. TrackNumber: one byte with range 0x00 through 0x0F. 0x00 = Track 0, 0x0F = Track 15. Pointer: three bytes with range 0x000000 through 0xFFFFFF. Defines an offset in the file.	C1 04 05 B4 73 C1: OpCode 04: Track 4 05 B4 73: Offset	Creates a Track which can play Notes. Track 15 is usually reserved for Yoshi Drums.
C2	JASSeqParser::cmdCloseTrack
C3	JASSeqParser::cmdCall	{OpCode[1]} {Pointer[3]} OpCode: one byte, C3. Pointer: three bytes with range 0x000000 through 0xFFFFFF. Defines an offset in the file.	C3 00 00 40 C3: OpCode 00 00 40: Offset	Redirects execution to the defined offset. Execution can return with C5.
C4	JASSeqParser::cmdCallF
C5	JASSeqParser::cmdRet	{OpCode[1]} OpCode: one byte, C5.		Returns redirected execution (like from C3) to the initial call.
C6	JASSeqParser::cmdRetF
C7	JASSeqParser::cmdJmp	{OpCode[1]} {Pointer[3]} OpCode: one byte, C7. Pointer: three bytes with range 0x000000 through 0xFFFFFF. Defines an offset in the file.	C7 08 02 34 C7: OpCode 08 02 34: Offset	Redirects execution to the defined offset, used for Loops.
C8	JASSeqParser::cmdJmpF
C9	JASSeqParser::cmdJmpTable
CA	JASSeqParser::cmdCallTable
CB	JASSeqParser::cmdLoopS
CC	JASSeqParser::cmdLoopE
CD	NULL
CE	NULL
CF	NULL
D0	JASSeqParser::cmdReadPort
D1	JASSeqParser::cmdWritePort
D2	JASSeqParser::cmdCheckPortImport
D3	JASSeqParser::cmdCheckPortExport
D4	JASSeqParser::cmdParentWritePort
D5	JASSeqParser::cmdChildWritePort
D6	JASSeqParser::cmdParentReadPort
D7	JASSeqParser::cmdChildReadPort
D8	JASSeqParser::cmdRegLoad
D9	JASSeqParser::cmdReg
DA	JASSeqParser::cmdReg
DB	JASSeqParser::cmdRegUni
DC	JASSeqParser::cmdRegTblLoad
DD	NULL
DE	NULL
DF	NULL
E0	JASSeqParser::cmdTempo	{OpCode[1]} {Unknown[1]} {BPM[1]} OpCode: one byte, E0. Unknown: one byte with unknown range and purpose. BPM: one byte with range 0x00 through 0xFF. 0x78 = 120, F0 = 240.	E0 00 90 E0: OpCode 00: Unknown 90: BPM 144	Defines the tempo (playback speed) of the BMS file.
E1	JASSeqParser::cmdBankPrg	{OpCode[1]} {Bank[1]} {Program[1]} OpCode: one byte, E1. Bank: one byte with range 0x00 through 0xFF. This byte represents a WSYS ID. Program: one byte ranging from 0x00 through 0xFF. This byte represents a LIST entry in the IBNK belonging to the defined WSYS ID.	E1 01 0F E1: OpCode 01: WSYS ID 1 0F: IBNK LIST entry 15 (01 0F is the percussion set for Yoshi Drums)	Defines the Instrument to be used in a Track.
E2	JASSeqParser::cmdBank	{OpCode[1]} {Bank[1]} OpCode: one byte, E2. Bank: one byte with range 0x00 through 0xFF. This byte represents a WSYS ID.	E2 53 E2: OpCode 53: WSYS ID 83 (This bank holds sounds for Megahammer)	Defines the WSYS/IBNK whose sounds are to be used in a Track.
E3	JASSeqParser::cmdPrg	{OpCode[1]} {Program[1]} OpCode: one byte, E3. Program: one byte with range 0x00 through 0xFF. This byte represents a LIST entry in the IBNK belonging to the defined WSYS ID.	E3 0B E3: OpCode 0B: IBNK LIST entry 11 (In relation to Megahammer, this Program holds movement related sounds)	Defines the Keyboard which holds more specific sounds to an IBNK.
E4	NULL
E5	NULL
E6	NULL
E7	JASSeqParser::cmdEnvScaleSet
E8	JASSeqParser::cmdEnvSet
E9	JASSeqParser::cmdSimpleADSR
EA	JASSeqParser::cmdBusConnect
EB	JASSeqParser::cmdIIRCutOff
EC	JASSeqParser::cmdIIRSet
ED	JASSeqParser::cmdFIRSet
EE	NULL
EF	NULL
F0	JASSeqParser::cmdWait	{OpCode[1]} {WaitTime[n]} OpCode: one byte, 0xF0. WaitTime: one or more bytes with range 0x00 through 0xFF. If the leading byte is 0x80 (bit 7 = 1) or greater, another following byte will be taken into account. Time is measured in ticks here.	F0 60 (96 Ticks) F0 81 56 (214 Ticks) F0 83 81 30 (49328 Ticks)	Creates a delay, used to define the length of a Note or gap between Notes.
F1	JASSeqParser::cmdWaitByte
F2	NULL
F3	JASSeqParser::cmdSetIntTable
F4	JASSeqParser::cmdSetInterrupt
F5	JASSeqParser::cmdDisInterrupt
F6	JASSeqParser::cmdRetI
F7	JASSeqParser::cmdClrI
F8	JASSeqParser::cmdIntTimer
F9	JASSeqParser::cmdSyncCPU
FA	NULL
FB	NULL
FC	NULL
FD	JASSeqParser::cmdPrintf
FE	JASSeqParser::cmdNop
FF	JASSeqParser::cmdFinish	{OpCode[1]} OpCode: one byte, 0xFF.		Stops execution of a Track.
B000	NULL
B001	JASSeqParser::cmdDump

Tools

BMS_DEC (converts BMS to MIDI)
JaiSeqX (playback for JAudio1 and JAudio2 BMS files)