Binary Wave Files (.bwav)

BWAVs, or Binary Waves are a new addition to the AAL library since SMM2. They are used how STMs are, but are in a structure that resembles a WAV. Since these are part of the AAL library and not NintendoWare, these do not follow the same common structures as other files. In fact, these files actually use absolute offsets.

The Main File

The main file consists of a File Header, an array of Channel Info, and an array of Channel Samples. There is padding to 0x40 before each structure.

Type	Description
FileHeader	File Header (Magic: BWAV)
ChannelInfo[NumChannels]	Channel Info
Padding	Padding to 0x40
ChannelSamples[NumChannels]	Array of Channel Samples. There is a padding of 0x40 before each channel’s samples

File Header

A really different header than most files. It is 0x10 bytes. A prefetch file is much smaller version of the original file to load audio data in when the normal track loads. I’ve only seen it have a sample count of 0x3800, which is 0x2000 bytes.

Offset	Type	Description
0x00	char[4]	Magic
0x04	u16	Byte Order. 0xFFFE in big endian is little endian
0x06	u16	Version. &0xFF00 » 8 is Major, &0xFF is Minor
0x08	u32	CRC32 Hash. Combine all channels’ sample data into one large byte array without padding, and CRC32 hash it to get this. This does not change when generating prefetch files
0x0C	u16	1 if prefetch file, otherwise 0
0x0E	u16	Num Channels. How many channels this file contains

Channel Info

Gives the game info about how to play the audio of a certain channel. It’s 0x4C bytes.

Offset	Type	Description
0x00	u16	Always seems to be 1
0x02	u16	Channel Pan. 0 for left, 1 for right, 2 for middle
0x04	u32	Sample Rate
0x08	u32	Number of samples in non-prefetch file
0x0C	u32	Number of samples in this file
0x10	s16[8][2]	DSP-ADPCM Coefficients
0x30	u32	Absolute start offset of the sample data in non-prefetch file
0x34	u32	Absolute start offset of the sample data in this file
0x38	u32	Is 1 if the channel loops
0x3C	u32	Loop End Sample (0xFFFFFFFF if doesn’t loop)
0x40	u32	Loop Start Sample (0 if doesn’t loop)
0x44	u16	Predictor Scale?
0x46	u16	History Sample 1?
0x48	u16	History Sample 2?
0x4A	u16	Padding?

Channel Samples

Each channel has its data stored using DSP-ADPCM encoding. The length of the the byte array of each channel is the length of the entire file minus the offset of the last channel. Before each channel’s sample array, the file is padded to 0x40 bytes, not at the end though.

Summary

A tree to sum up the structure of the file:

BWAV File:
|-File Header
|
|-Channel Info[NumChannels]
|    |-Information about each channel.
|
|-Channel Samples

Citric-Composer