AST (File Format)
AST files are audio streams found in several JAudio2 games, including Super Mario Galaxy and Super Mario Galaxy 2. Both games store their AST files in the AudioRes/Stream directory.
For a comprehensive list linking AST files to the Galaxy they're used in, check the List of Music page.
Header
AST file header, 0x40 bytes in length.
| Offset | Type | Description |
|---|---|---|
| 0x00 | String | File magic. STRM in ASCII |
| 0x04 | UInt32 | Size of all blocks. File size - header length (0x40) |
| 0x08 | UInt16 | Audio format: 0 = ADPCM, 1 = PCM16 |
| 0x0A | UInt16 | Bit depth |
| 0x0C | UInt16 | Number of channels |
| 0x0E | UInt16 | Loop enabled: 0x0000 if no loop, 0xFFFF if loop |
| 0x10 | UInt32 | Sample rate |
| 0x14 | UInt32 | Total sample count |
| 0x18 | UInt32 | Loop start in samples |
| 0x1C | UInt32 | Loop end in samples |
| 0x20 | UInt32 | Default data size per channel in a block |
| 0x24 | UInt32 | Unknown. Always 0 |
| 0x28 | UInt32 | Volume. Always 0x7F000000 |
| 0x2C | Byte | Always 0. Likely padding |
| 0x40 | End of header |
BLCK
AST files contain multiple BLCK sections, each containing sound data.
| Offset | Type | Description |
|---|---|---|
| 0x00 | String | Block magic. BLCK in ASCII |
| 0x04 | UInt32 | Block size; the data size per channel in this block |
| 0x08 | UInt16 | ADPCM only: channel 1 last value |
| 0x0A | UInt16 | ADPCM only: channel 1 penult value |
| 0x0C | UInt16 | ADPCM only: channel 2 last value |
| 0x0E | UInt16 | ADPCM only: channel 2 penult value |
| 0x10 | UInt16 | ADPCM only: channel 3 last value |
| 0x12 | UInt16 | ADPCM only: channel 3 penult value |
| 0x14 | UInt16 | ADPCM only: channel 4 last value |
| 0x16 | UInt16 | ADPCM only: channel 4 penult value |
| 0x18 | UInt16 | ADPCM only: channel 5 last value |
| 0x1A | UInt16 | ADPCM only: channel 5 penult value |
| 0x1C | UInt16 | ADPCM only: channel 6 last value |
| 0x1E | UInt16 | ADPCM only: channel 6 penult value |
| 0x20 | Byte | Sound data |
Tools
Tutorials
Luma's Workshop - Changing Background Music
Luma's Workshop - Importing New Music Tracks