BRSEQ (File Format)
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 | Offset to data (Relative to start of this header). |
Commands
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 VLQ 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 + VLQ | 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. |
| 0x80 | VLQ | Wait. Parameter describes the time (48 = quarter note) |
| 0x81 | VLQ | Sets the program number to use (Instrument ID inside Bank File) |
| 0x88 | Byte + UInt24 | Start another track. First argument is track number, the second one is the offset (relative to the start of the sound data) |
| 0x89 | Int24 | Jump to the given offset (relative to the start of the sound data) |
| 0x8a | Int24 | Call the given offset (push stack) |
| 0xb0 | Byte | Time base (quarter note resolution) |
| 0xb1 | Byte | Envelope Hold |
| 0xb2 | Byte | Monophonic |
| 0xb3 | Byte | Velocity Range (Not supported by Mario Kart Wii) |
| 0xc0 | Byte | Pan |
| 0xc1 | Byte | Volume |
| 0xc2 | Byte | Main Volume |
| 0xc3 | Byte | Transpose |
| 0xc4 | Byte | Pitchbend |
| 0xc5 | Byte | Pitchbend Range |
| 0xc6 | Byte | Priority |
| 0xc7 | Byte | Note Wait enable |
| 0xc8 | Byte | Tie enable |
| 0xc9 | Byte | Use portamento (pitch sliding time). Argument is the start key |
| 0xca | Byte | Modulation Depth |
| 0xcb | Byte | Modulation Speed |
| 0xcc | Byte | Modulation Type |
| 0xcd | Byte | Modulation Range |
| 0xce | Byte | Portamento Speed |
| 0xcf | Byte | Portamento Time |
| 0xd0 | Byte | Attack (time until full amplitude is reached) |
| 0xd1 | Byte | Decay (time until the sustain amplitude is reached after full amplitude) |
| 0xd2 | Byte | Sustain level |
| 0xd3 | Byte | Release (time between a key release and zero amplitude) |
| 0xd4 | Byte | Loop start (Count) |
| 0xd5 | Byte | Volume 2 (Total volume = Volume 1 * Volume 2) |
| 0xd6 | Byte | Print variable (variable index; used for debugging) |
| 0xd7 | Byte | Surround Pan |
| 0xd8 | Byte | LPF cut-off frequency |
| 0xd9 | Byte | FXSend A |
| 0xda | Byte | FXSend B |
| 0xdb | Byte | Main Send |
| 0xdc | Byte | Initial Pan |
| 0xdd | Byte | Mute enable |
| 0xde | Byte | FXSend C |
| 0xdf | Byte | Damper |
| 0xe0 | Int16 | Modulation Delay |
| 0xe1 | Int16 | Change Tempo (Default: 120) |
| 0xe3 | Int16 | Sweep |
| 0xf0 | Byte + Byte + Int16 | Extended command (see table below) |
| 0xfc | - | End loop. |
| 0xfd | - | Return (pop stack) |
| 0xfe | Int16 | Allocate tracks (bitmask, starting from the lowest order bit as Track 0 up to Track 15; Track 0 ignored since it's always allocated) |
| 0xff | - | End of input |
Extended Commands
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 | = 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 |
Prefix Commands
Prefix Commands define modifiers that allow settings to be made with a greater degree of freedom. Prefix Commands can be chained together.
| Command | Arguments | Description |
|---|---|---|
| 0xa0 | Byte[2] | Executes the command of following byte with a random number between the two provided shorts as first argument. |
| 0xa1 | Byte | Executes the command of following byte with the value of a variable at the provided index as argument. |
| 0xa2 | - | Process the following command only if a preceding comparison was true. |
| 0xa3 | * + Int16 | 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 | * + Int16 | Same as 0xa0, with time factor. |
| 0xa5 | * + Int16 | Same as 0xa1, with time factor. |
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)