BFWAV (File Format)

BFWAV (Binary caFe WAVe) is common file format for storing sound on Wii U and Nintendo Switch. The format is structured similarly to WAV, where there is one info section ("fmt " in WAV, "INFO" in BFWAV) and one data section ("data" in WAV, "DATA" in BFWAV). The file consists of a header and two sections, INFO and DATA. All offsets in the file may be 0xFFFFFFFF if it links to nothing.

File Format

Header

The file starts with a header as follows:

Offset	Type	Description
0x00	Char[4]	File magic. Always FWAV in ASCII.
0x04	UInt16	Byte-order-mark. FE FF for big endian, FF FE for little endian.
0x06	UInt16	Header size. Always 0x40 due to alignment.
0x08	UInt32	Version number.
0x0C	UInt32	File size in bytes.
0x10	UInt16	Number of sections. Always 2.
0x12	UInt16	Padding.
0x14	UInt16	INFO section flag. Always 0x7000.
0x16	UInt16	Padding.
0x18	UInt32	INFO offset.
0x1C	UInt32	INFO size in bytes.
0x20	UInt16	DATA section flag. Always 0x7001.
0x22	UInt16	Padding.
0x24	UInt32	DATA offset.
0x28	UInt32	DATA size in bytes.
0x2C	Byte[0x14]	Padding to align the data.
0x40	End of header

INFO

The INFO section contains general information about the sound.

Offset	Type	Description
0x00	Char[4]	Section magic. Always INFO in ASCII.
0x04	UInt32	Section size in bytes.
0x08	Byte	Sound encoding. 0 = PCM8, 1 = PCM16, 2 = DSP ADPCM, 3 = IMA ADPCM.
0x09	Byte	Loop. 0 = no loop, 1 = loop.
0x0A	Byte[2]	Padding.
0x0C	UInt32	Sample rate.
0x10	UInt32	Loop start in frames. 0 if not looping.
0x14	UInt32	Loop end in frames. 0 if not looping.
If version ≥ 0.1.2.0
0x18	UInt32	Original loop start. 0 if not looping.
Else
0x18	UInt32	Reserved.

Then follows a reference table which points to the channel infos. The section flag is 0x7100.

Channel Info

The Channel Info section contains an offset to the data and may contain ADPCM information. Each entry has the following structure:

Offset	Type	Description
0x00	UInt16	Sound data offset flag. Always 0x1F00.
0x02	UInt16	Padding.
0x04	Int32	Sound data offset, relative to 0x08 into the DATA section.
0x08	UInt16	ADPCM info flag. Always 0x0300.
0x0A	UInt16	Padding.
0x0C	Int32	ADPCM info offset, relative to the start of this structure.
0x10	UInt32	Reserved.

ADPCM Info

Offset	Type	Description
0x00	UInt16[8][2]	16-bit Coefficients.
0x20	UInt16	Pred scale.
0x22	UInt16	Yn 1.
0x24	UInt16	Yn 2.
0x26	UInt16	Loop Pred Scale.
0x28	UInt16	Loop Yn 1.
0x2A	UInt16	Loop Yn 2.
0x2C	UInt16	Padding.

DATA

The DATA section contains all the sound data.

Offset	Type	Description
0x00	Char[4]	Section magic. Always DATA in ASCII.
0x04	UInt32	S = Section size in bytes.
0x08	Byte[S - 8]	Sound data.

Reference Table

A reference table is used to reference multiple structures. It has the following structure:

Offset	Type	Description
0x00	UInt32	Number of references.

The following structure follows. The amount is specified above.

Offset	Type	Description
0x00	UInt16	Section flag, to identify what structure it links to.
0x02	UInt16	Padding.
0x04	Int32	Offset to a structure, relative to the start of the header structure.

Version List

Version	Found in
0.1.1.0	Mario Kart 8
0.1.2.0	1-2-Switch ARMS Game Builder Garage Everybody 1-2-Switch! Mario Golf: Super Rush Mario Kart 8 Deluxe Mario Kart 8 Deluxe (S00018080-R00018076-A00000000 Prototype) Nintendo Labo - Toy-Con 01: Variety Kit Nintendo Labo - Toy-Con 02: Robot Kit Nintendo Labo - Toy-Con 03: Vehicle Kit Nintendo Labo - Toy-Con 04: VR Kit PAC-MAN 99 Paper Mario: The Origami King Paper Mario: The Thousand-Year Door (Nintendo Switch) Pikmin 3 Deluxe Splatoon 2 Super Mario Maker The Legend of Zelda: Breath of the Wild (Nintendo Switch)

Tools

The following tools can handle BFWAV files:

• Wexos's Toolbox, by Wexos.