BCWAV

This document is about the format of Binary CTR Wave files (BCWAV). The structure is very similar to Microsoft's Wave file.

Overview[edit]

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).

Header[edit]

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)

Block Header[edit]

OFFSET	SIZE	DESCRIPTION
0x000	4	Magic
0x004	4	Size

Block Types[edit]

MAGIC	TYPE
INFO	Info Block
DATA	Data Block

Info Block[edit]

OFFSET	SIZE	DESCRIPTION
0x000	8	Block Header
0x008	1	Encoding
0x009	1	Loop (0 = don't loop, 1 = loop)
0x00A	2	Padding
0x00C	4	Sample Rate
0x010	4	Loop Start Frame
0x014	4	Loop End Frame
0x018	4	Reserved
0x01C	X	Channel Info Reference Table
X	X	Channel Info Entries

If encoding is DSP ADPCM:

OFFSET	SIZE	DESCRIPTION
X	X	DSP ADPCM Info Entries

If encoding is IMA ADPCM:

OFFSET	SIZE	DESCRIPTION
X	X	IMA ADPCM Info Entries

The info block is aligned to 0x20 bytes.

Encoding[edit]

VALUE	DESCRIPTION
0	PCM8
1	PCM16
2	DSP ADPCM
3	IMA ADPCM

Channel Info[edit]

OFFSET	SIZE	DESCRIPTION
0x000	8	Samples Reference (Offset relative to Data Block Data field)
0x008	8	ADPCM Info Reference (Offset relative to Samples Reference field)
0x010	4	Reserved

DSP ADPCM Info[edit]

OFFSET	SIZE	DESCRIPTION
0x000	32	Param
0x020	6	Context
0x026	6	Loop Context
0x02C	2	Padding

DSP ADPCM Param[edit]

OFFSET	SIZE	DESCRIPTION
0x000	32	16-bit Coefficients

DSP ADPCM Context[edit]

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[edit]

OFFSET	SIZE	DESCRIPTION
0x000	4	Context
0x004	4	Loop Context

IMA ADPCM Context[edit]

OFFSET	SIZE	DESCRIPTION
0x000	2	Data
0x002	1	Table Index
0x003	1	Padding

Data Block[edit]

OFFSET	SIZE	DESCRIPTION
0x000	8	Block Header
0x008	Block Header Size Value - 8	Data

The data block is aligned to 0x20 bytes, as well as the data field's actual sample data.

Reference Table[edit]

OFFSET	SIZE	DESCRIPTION
0x000	4	Count
0x004	Count * 8	References (Offsets relative to Count field)

Sized Reference[edit]

OFFSET	SIZE	DESCRIPTION
0x000	8	Reference
0x008	4	Size

Reference[edit]

OFFSET	SIZE	DESCRIPTION
0x000	2	Type ID
0x002	2	Padding
0x004	4	Offset ("null" = 0xFFFFFFFF)

Reference Types[edit]

ID	TYPE
0x0300	DSP ADPCM Info
0x0301	IMA ADPCM Info
0x1F00	Sample Data
0x7000	Info Block
0x7001	Data Block
0x7100	Channel Info