This document is about the format of Binary CTR Wave files (BCWAV). The
structure is very similar to Microsoft’s Wave file.
Overview
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Microsoft’s WAV structure is RIFF Header which defines the data inside
which is WAVE, then the media player expects a “fmt " chunk and a “data”
chunk. Nintendo’s format uses a CWAV header (no need for a general
structure for media, only wave), which points to an INFO struct (the
equivalent to fmt) and a DATA struct (the equivalent to data).
| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 4 | Magic (CWAV) |
| 0x004 | 2 | Endianness (0xFEFF = little, 0xFFFE = big) |
| 0x006 | 2 | Header Size (0x40 due to
Info Block alignment) |
| 0x008 | 4 | Version (0x02010000) |
| 0x00C | 4 | File Size |
| 0x010 | 2 | Number of Blocks (2) |
| 0x012 | 2 | Reserved |
| 0x014 | 12 | Info Block
Sized Reference (Offset relative to start of file) |
| 0x020 | 12 | Data Block
Sized Reference (Offset relative to start of file) |
| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 4 | Magic |
| 0x004 | 4 | Size |
Block Types
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Info Block
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If encoding is DSP ADPCM:
If encoding is IMA ADPCM:
The info block is aligned to 0x20 bytes.
Encoding
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| VALUE | DESCRIPTION |
|---|
| 0 | PCM8 |
| 1 | PCM16 |
| 2 | DSP ADPCM |
| 3 | IMA ADPCM |
Channel Info
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DSP ADPCM Info
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DSP ADPCM Param
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| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 32 | 16-bit Coefficients |
DSP ADPCM Context
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| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 1 | 4-bit Predictor + 4-bit Scale |
| 0x001 | 1 | Reserved |
| 0x002 | 2 | Previous Sample |
| 0x004 | 2 | Second Previous Sample |
IMA ADPCM Info
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IMA ADPCM Context
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| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 2 | Data |
| 0x002 | 1 | Table Index |
| 0x003 | 1 | Padding |
Data Block
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The data block is aligned to 0x20 bytes, as well as the data field’s
actual sample data.
Reference Table
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| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 4 | Count |
| 0x004 | Count * 8 | References (Offsets relative to Count field) |
Sized Reference
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| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 8 | Reference |
| 0x008 | 4 | Size |
Reference
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| OFFSET | SIZE | DESCRIPTION |
|---|
| 0x000 | 2 | Type ID |
| 0x002 | 2 | Padding |
| 0x004 | 4 | Offset (“null” = 0xFFFFFFFF) |
Reference Types
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Category:File formats