BCWAV

This document is about the format of Banner's CTR Wave files (BCWAV).

The structure is very similar to Microsoft's Wave file.

Banner CWAV total channels must be 2, and the length of the audio in seconds must be 3 seconds or less.

Overview

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

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

OFFSET	SIZE	DESCRIPTION
0x000	4	Magic
0x004	4	Size

Block Types

MAGIC	TYPE
INFO	Info Block
DATA	Data Block

Info Block

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

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

Channel Info

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

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

DSP ADPCM Param

OFFSET	SIZE	DESCRIPTION
0x000	32	16-bit Coefficients

DSP ADPCM Context

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

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

IMA ADPCM Context

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

Data Block

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

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

Sized Reference

OFFSET	SIZE	DESCRIPTION
0x000	8	Reference
0x008	4	Size

Reference

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

Reference Types

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