Difference between revisions of "SND"
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[[Category:Music]] | [[Category:Music]] | ||
The SND file, also known as DTPK, is used for both sequenced music and packages of sound effects.<br> | The SND file, also known as DTPK, is used for both sequenced music and packages of sound effects.<br> | ||
The format is played back via the AM2 AICA driver, located as AICADRV.BIN in the MISC folder on the Dreamcast versions of the game | The format is played back via the AM2 AICA driver, located as AICADRV.BIN in the MISC folder on the Dreamcast versions of the game. | ||
SND File format | SND File format | ||
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AICA Driver Commands | ===AICA Driver=== | ||
The AICA driver is loaded right into the start of AICA RAM at 0. The driver always loads the SND file for music into the hard-coded offset of 0x10000. Subsequent files can be loaded after that, the offset(s) written to a table found at 0xDB00 with 0x20 byte entries per file. The table contains 8 slots, (ends at 0xDC00) and they don't always need to be filled in order. This loaded files table will be further documented later. | |||
===AICA Driver Commands=== | |||
There is a rolling buffer from 0x400 to 0x500 in memory where 4 byte commands are sent to the driver. As each command is executed, the sound driver clears those bytes back to 00. New commands should be sent to the next set of 4 bytes and roll back to 0x400 once you hit 0x500. Commands to be documented when further understood. | |||
Latest revision as of 04:29, 19 March 2021
The SND file, also known as DTPK, is used for both sequenced music and packages of sound effects.
The format is played back via the AM2 AICA driver, located as AICADRV.BIN in the MISC folder on the Dreamcast versions of the game.
SND File format
Header
| Position | Length | Type | Description |
|---|---|---|---|
| 0x00 | 0x04 | string | Identifier 0x4454504B (DTPK) |
| 0x08 | 0x04 | uint | Size of file |
| 0x3C | 0x04 | uint | Location of Sample Table |
Sample Table
| Position | Length | Type | Description |
|---|---|---|---|
| 0x00 | 0x04 | uint | Index of last sample (Add 1 for number of samples) |
| 0x04 | N/A | N/A | First sample entry (0x10 bytes each) |
Sample Entries
| Position | Length | Type | Description |
|---|---|---|---|
| 0x00 | 0x04 | uint | Sample Location & Type packed as follows: |
| & 0x007FFFFF | Sample Offset | ||
| & 0x00800000 | Sample quality. 0 Normal, 1 Half | ||
| & 0x01000000 | Format flag - 0 PCM, 1 ADPCM | ||
| & 0x02000000 | Unknown flag. Is NOT Mono/Stereo | ||
| 0x04 | 0x2 | ushort | Loop start offset from start of sample |
| 0x06 | 0x2 | ushort | Loop end offset from start of sample |
| 0x08 | 0x4 | uint | Related to sample frequency. Either 0 or 0x80. 0x80 = Half sample rate |
| 0x0C | 0xC | uint | Size of sample data |
AICA Driver
The AICA driver is loaded right into the start of AICA RAM at 0. The driver always loads the SND file for music into the hard-coded offset of 0x10000. Subsequent files can be loaded after that, the offset(s) written to a table found at 0xDB00 with 0x20 byte entries per file. The table contains 8 slots, (ends at 0xDC00) and they don't always need to be filled in order. This loaded files table will be further documented later.
AICA Driver Commands
There is a rolling buffer from 0x400 to 0x500 in memory where 4 byte commands are sent to the driver. As each command is executed, the sound driver clears those bytes back to 00. New commands should be sent to the next set of 4 bytes and roll back to 0x400 once you hit 0x500. Commands to be documented when further understood.