BRSTM (File Format)

This article describes the BRSTM format, the music format used by Mario Kart Wii, Super Smash Bros. Brawl, and many others.

File Header

The file begins with the header, which is 0x64 bytes. All lengths are written in Decimal.

Offset	Size	Description
0x00	4	File identifier: 'RSTM' in ASCII.
0x04	2	Byte order mark. 0xFEFF is the big endian byte order, 0xFFFE is little endian.
0x06	2	Unknown (Usually 01 00)
0x08	4	Length of the file in bytes.
0x0c	2	Length of header in bytes. (Always 00 40)
0x0e	2	Unknown (00 02 in most files).
0x10	4	Offset location of the HEAD section. (Usually 00 00 00 40)
0x14	4	Size of HEAD section in bytes.
0x18	4	Offset location of ADPC section in bytes.
0x1c	4	Size of ADPC section in bytes.
0x20	4	Offset location of DATA section in bytes.
0x24	4	Size of DATA section in bytes.
0x28	24	Unknwon (Consists of only 00)
End of header

Sections

The rest of the file is written like an Adaptive differential pulse code modulation (ADPCM) file.

HEAD

The HEAD section is typically 256 bytes long.

It contains what appears to be a ADPCM Table, followed by a a YN1 & YN2 twice, which may control looping.

The rest is unknown.

ADPC

The ADPC section contains what looks like another table. All lengths are written in decimal.

Offset	Size	Description
0x00	4	Section header: 'ADPC' in ASCII.
0x04	4	Length of section in bytes (Typically 00 00 21 60)
0x08	1216	Null bytes (00)
End of section

DATA

The DATA section contains the ADPCM data, the sounds the file make. All lengths are written in hexadecimal.

Offset	Size	Description
0x00	4	Section header: 'DATA' in ASCII.
0x04	4	Length of section in bytes (L = Section Length)
0x08	4	Unknown (Number of sub-sections in the ADPCM data?)
0x0b	14	Padding/Null Bytes
0x20	L	ADPCM Data
0x30 + L	10	Padding
End of section
End of file