VGM commands

From the data offset, a VGM file is one command after another, each a command byte with operands. The stream ends at command 66. An unknown command stops processing; a reserved command must be skipped by its operand count. Timing comes from the wait commands, in samples at 44,100 per second. All codes on this page are hexadecimal. Commands are listed up to specification 1.71.

Chip writes

Each writes to a chip register. aa is the register, dd the value.

Command	Operands	Chip
30	dd	Second SN76489
3F	dd	Second Game Gear PSG stereo
4F	dd	Game Gear PSG stereo, port 06
50	dd	SN76489/SN76496
51	aa dd	YM2413
52, 53	aa dd	YM2612 port 0, port 1
54	aa dd	YM2151
55	aa dd	YM2203
56, 57	aa dd	YM2608 port 0, port 1
58, 59	aa dd	YM2610 port 0, port 1
5A	aa dd	YM3812
5B	aa dd	YM3526
5C	aa dd	Y8950
5D	aa dd	YMZ280B
5E, 5F	aa dd	YMF262 port 0, port 1
A0	aa dd	AY8910
A1	aa dd	YM2413, second chip
A2, A3	aa dd	YM2612 port 0, port 1, second chip
A4	aa dd	YM2151, second chip
A5	aa dd	YM2203, second chip
A6, A7	aa dd	YM2608 port 0, port 1, second chip
A8, A9	aa dd	YM2610 port 0, port 1, second chip
AA	aa dd	YM3812, second chip
AB	aa dd	YM3526, second chip
AC	aa dd	Y8950, second chip
AD	aa dd	YMZ280B, second chip
AE, AF	aa dd	YMF262 port 0, port 1, second chip
B0	aa dd	RF5C68
B1	aa dd	RF5C164
B2	ad dd	PWM: register a, value ddd (d is the top nibble)
B3	aa dd	GameBoy DMG: register 00 is address `FF10`
B4	aa dd	NES APU: 00–1F map to `4000`–`401F`, 20–3E to `4080`–`409E`, 3F to `4023`, 40–7F to `4040`–`407F`
B5	aa dd	MultiPCM
B6	aa dd	uPD7759
B7	aa dd	OKIM6258
B8	aa dd	OKIM6295
B9	aa dd	HuC6280
BA	aa dd	K053260
BB	aa dd	Pokey
BC	aa dd	WonderSwan
BD	aa dd	SAA1099
BE	aa dd	ES5506, 8-bit value
BF	aa dd	GA20
D0	pp aa dd	YMF278B, port pp
D1	pp aa dd	YMF271, port pp
D2	pp aa dd	SCC1, port pp
D3	pp aa dd	K054539, register ppaa
D4	pp aa dd	C140, register ppaa
D5	pp aa dd	ES5503, register ppaa
D6	aa dd ee	ES5506, 16-bit value ddee to register aa
E1	aa bb dd ee	C352, 16-bit value ddee to register aabb

The AY8910 stereo mask is command 31. A second chip that has no command of its own is addressed through bit 7 of the first operand. For Sega PCM, that bit is in the high byte of the memory address.

Memory writes

Command	Operands	Meaning
C0	bb aa dd	Sega PCM: write dd to memory offset aabb
C1	bb aa dd	RF5C68: memory offset aabb
C2	bb aa dd	RF5C164: memory offset aabb
C3	cc bb aa	MultiPCM: set bank offset aabb for channel cc
C4	mm ll rr	QSound: write value mmll to register rr
C5	mm ll dd	SCSP: memory offset mmll
C6	mm ll dd	WonderSwan: memory offset mmll
C7	mm ll dd	VSU: register mmll
C8	mm ll dd	X1-010: memory offset mmll

Waits and flow

Command	Operands	Meaning
61	nn nn	Wait `n` samples, 0 to 65,535.
62		Wait 735 samples: one 60 Hz frame.
63		Wait 882 samples: one 50 Hz frame.
66		End of the sound data.
67	…	Data block.
68	…	PCM RAM write.
70–7F		Wait `n` + 1 samples, `n` being the low nibble (0 to 15).
80–8F		YM2612 port 0 address `2A` write from the data bank, then wait `n` samples (the low nibble, 0 to 15). First chip only.
90–95	…	DAC stream control.
E0	dd dd dd dd	Seek to offset dddddddd in the PCM data bank.

AY8910 stereo mask (command 31)

One operand dd:

Bits	Meaning
0–1	Channel A: 00 off, 01 left, 10 right, 11 centre.
2–3	Channel B, the same.
4–5	Channel C, the same.
6	Chip type: 0 AY8910, 1 YM2203 SSG.
7	Chip number: 0 or 1.

Reserved commands

Commands	Operands to skip
32–3E	1
40–4E	2 (1 until version 1.60)
C9–CF	3
D7–DF	3
E2–FF	4

60, 64, 65, 69 to 6F and 96 to 9F are undefined.

.VGM File Format – Commands

Chip writes

Memory writes

Waits and flow

AY8910 stereo mask (command 31)

Reserved commands