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BFSEQ File Format
NW > Sound Files > Sequence Sound (FSEQ)
This file contains a sequence sound. A sequence sound specifies which notes should be played at what time using instruments from a bank file.
| Block id | Description |
|---|---|
0x5000 |
Data block |
0x5001 |
Label block |
| Offset | Size | Description |
|---|---|---|
| 0x0 | 4 | Identifier ("INFO") |
| 0x4 | 4 | Block size |
| 0x8 | Data |
A sequence track consists of a stream of commands. These are stored in the data block. Every command starts with a single byte that specifies the type of the command, which is usually followed by one or more parameters (depending on the command).
Time is divided into beats, which are futher divided into ticks. The default number of beats per minute is 120, and the default number of ticks per beat is 48.
Some commands operate on variables. These are accessed by index, and can be divided into the following categories:
| Variable | Description |
|---|---|
| 0 - 15 | Local variables (per sequence file) |
| 16 - 31 | Global variables (shared for all sequence files) |
| 32 - 47 | Track variables (per sequence track) |
| Command | Description |
|---|---|
| 0x0 - 0x7F | Play note |
| 0x80 | Sleep |
| 0x81 | Change instrument |
| 0x88 | Start track |
| 0x89 | Jump |
| 0xB0 | Set ticks per beat |
| 0xE1 | Set beats per minute |
| 0xF0 | Extended command |
| 0xFE | Allocate tracks |
| 0xFF | End |
Some commands take an integer of variable length. This integer is parsed as follows:
def read_varint():
value = 0
while True:
byte = read_u8()
value = (value << 7) | (byte & 0x7F)
if not byte & 0x80:
return valueAll commands between 0 and 127 play a note. The command number specifies the 'key'.
| Type | Description |
|---|---|
| Uint8 | Velocity |
| Varint | Length |
| Type | Description |
|---|---|
| Varint | Number of ticks |
| Type | Description |
|---|---|
| Varint | Instrument index |
| Type | Description |
|---|---|
| Uint8 | Track index |
| Uint24 | Start offset |
This is a simple control flow command.
| Type | Description |
|---|---|
| Uint24 | Offset into data block |
| Type | Description |
|---|---|
| Uint8 | Ticks per beat |
| Type | Description |
|---|---|
| Uint16 | Beats per minute |
This command specifies the number of tracks that are allocated for this sequence sound. If present, this command must be the first command in the data block.
| Type | Description |
|---|---|
| Uint16 | Track mask |
This command stops the current track.
This command starts with a single byte that indicates the type of its subcommand.
| Subcommand | Description |
|---|---|
| 0x80 - 0x8B | Variable operation |
| 0x90 - 0x95 | Variable comparison |
| Type | Description |
|---|---|
| Uint8 | Variable index |
| Int16 | Value |
| Command ID | Description |
|---|---|
| 0x80 | var = value |
| 0x81 | var = var + value |
| 0x82 | var = var - value |
| 0x83 | var = var * value |
| 0x84 | var = var / value |
| 0x85 |
var = var << value (negative value shifts to right instead) |
| 0x86 |
var is set to random value between 0 and value
|
| 0x87 | var = var & value |
| 0x88 | var = var | value |
| 0x89 | var = var ^ value |
| 0x8A | var = ~value |
| 0x8B | var = var % value |
| Type | Description |
|---|---|
| Uint8 | Variable index |
| Int16 | Value |
This command compares a variable with a given value and writes the result (0 or 1) into the internal condition register of the command processor.
| Command ID | Description |
|---|---|
| 0x90 | var == value |
| 0x91 | var >= value |
| 0x92 | var > value |
| 0x93 | var <= value |
| 0x94 | var < value |
| 0x95 | var != value |
| Offset | Size | Description |
|---|---|---|
| 0x0 | 4 | Identifier ("LABL") |
| 0x4 | 4 | Block size |
| 0x8 | 4 | Number of labels |
| 0xC | References to labels (0x5100) |
All labels are aligned to 4 bytes.
| Offset | Size | Description |
|---|---|---|
| 0x0 | 8 | Reference into data block (0x1F00) |
| 0x8 | 4 | Name length without null terminator |
| 0xC | Null-terminated label name |