BRSEQ (File Format)

Under Construction

This article is not finished. Help improve it by adding accurate information or correcting grammar and spelling.

BRSEQ (Binary Revolution SEQuence) is a sub file format found in BRSAR files from games like Mario Kart Wii. It corresponds to the music data represented in a MIDI-like file, but in binary. Commands that process changes in attributes such as sound generation and volume change over time are described on this kind of file. Since the sequence data is simply a set of commands, sounds are actually producing using bank data (stored in BRBNK sub files) that corresponds to the sound source data.

File Format

File Header

The file starts with a file header that is 0x20 bytes long.

Offset	Type	Description
0x00	String	File magic. Always RSEQ in ASCII.
0x04	UInt16	Byte order mark (BOM): The value is always 0xFEFF. If value 0xFFFE is read, then the false endian is used. Mario Kart Wii uses nearly always big endian (bytes 0xFE,0xFF).
0x06	UInt16	Version number of the file format.
0x08	UInt32	Length of the file in bytes.
0x0C	UInt16	Length of this header in bytes.
0x0E	UInt16	Number of sections.
0x10	UInt32	Offset to DATA section.
0x14	UInt32	Length of DATA section.
0x18	UInt32	Offset to LABL section.
0x1C	UInt32	Length of LABL section.
0x20	End of this file header

DATA

The DATA starts with a header.

Offset	Type	Description
0x00	String	Section magic. Always DATA in ASCII.
0x04	UInt32	Length of this section.
0x08	UInt32	Length of this header (always 0x0C).

After the header, the sound data is specified. It contains a series of bytes that represent different commands and parameters for the sound. The known commands and the format of their parameters are listed below. The 'Midi' type is a variable length argument whereby the most significant bit is used to tell the reader if the next byte should also be considered. A value of 1aaaaaaa 0bbbbbbb for example is converted to aaaaaaabbbbbbb.

Command	Arguments	Description
<0x80	Byte + Midi	Plays a note. The command is the key (pitch), the first argument the velocity (how hard the key is struck) and the midi variable is the time the key is held.
0x81	Midi	Sets the program number to use (sound idx in the bank file?)
0x89	Byte[3]	Jump to the given offset (relative to the start of the sound data)
0x8a	Byte[3]	Call the given offset (push stack)
0xa0	Cmd + Short[2]	Executes the command of following byte with a random number between the two provided shorts as first argument
0xa1	Cmd + Byte	Executes the command of following byte with the value of a variable at the provided index as argument
0xa2	Cmd + *	Process the following command only if a preceding comparison was true
0xa3	Cmd + * + Short	Add a time factor (ex. fade-in) to operations that support it. The time is provided as an additional short that follows the next command's arguments.
0xa4	Cmd + * + Short	Same as 0xa0, with time factor.
0xa5	Cmd + * + Short	Same as 0xa1, with time factor.
0xb1	Byte	Release (time between a key release and zero amplitude)
0xc1	Byte	Volume
0xc8	Byte	Tie enable
0xd0	Byte	Portamento time
0xd1	Byte	Attack (time until full amplitude is reached)
0xd2	Byte	Decay (time until the sustain amplitude is reached after full amplitude)
0xd3	Byte	Sustain level
0xc9	Byte	Use portamento (pitch sliding time). Use of argument unknown.
0xf0	Byte + Byte + Short	Extended command (see table below)
0xfd	-	Return (pop stack)
0xff	-	End of input

There also exist a number of extended commands. These typically take the form of F0 AA BB CC CC, with AA being the command and B and C being the first and second argument to this command. Preceding 0xa* commands can change the data format of C.

Command	Description
0x80	Variable at index B is set to C (Var[B] = C)
0x81	Var[B] += C
0x82	Var[B] -= C
0x83	Var[B] *= C
0x84	Var[B] /= C
0x85	Var[B] = Var[B] << C (reversed if C is negative)
0x86	Var[B] = random between 0 and C
0x87	Var[B] &= C
0x88	Var[B] OR= C
0x89	Var[B] ^= C
0x8a	Var[B] = ~C
0x8b	Var[B] %= C
0x90	Var[B] == C (comparison)
0x91	Var[B] >= C
0x92	Var[B] > C
0x93	Var[B] <= C
0x94	Var[B] < C
0x95	Var[B] != C

LABL

Offset	Type	Description
0x00	String	Section magic. Always LABL in ASCII.
0x04	UInt32	Length of this section.
0x08	UInt32	N = Number of sound labels.
0x0C	UInt32[N]	Offset to label, relative to offset 0x08 in this header.

This is the label structure.

Offset	Type	Description
0x00	UInt32	Offset to the sound data this label uses. Relative to the end of the DATA header.
0x04	UInt32	L = Length of label string.
0x08	String	Label name.

Tools

The following tools can handle BRSEQ files:

• rseq2midi (Converts BRSEQ to MIDI)