AST (File Format)
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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