BFSTM (File Format)

The BFSTM (Binary caFe STreaM) file format is used for storing music streams on Wii U and Nintendo Switch. It is a direct update from its predecessors, BRSTM and BCSTM, and is therefore very similar to them. It is also similar to BFWAV. The file consists of a header along with three sections, INFO, SEEK and DATA. All offsets in the file may be 0xFFFFFFFF if it links to nothing.

File Format

Header

The file starts with a 0x40 byte long header as follows:

Offset	Type	Description
0x00	Char[4]	File magic. Always FSTM in ASCII.
0x04	UInt16	Byte-order-mark. FE FF for big endian, FF FE for little endian.
0x06	UInt16	Header size. Always 0x40.
0x08	UInt32	Version number.
0x0C	UInt32	Size of the file in bytes.
0x10	UInt16	Number of data blocks in the file. Always 3 (INFO, SEEK and DATA).
0x12	UInt16	Padding.
0x14	UInt16	INFO section flag. Always 0x4000.
0x16	UInt16	Padding.
0x18	Int32	INFO offset.
0x1C	UInt32	INFO size.
0x20	UInt16	SEEK section flag. Always 0x4001.
0x22	UInt16	Padding.
0x24	Int32	SEEK offset.
0x28	UInt32	SEEK size.
0x2C	UInt16	DATA section flag. Always 0x4002.
0x2E	UInt16	Padding.
0x30	Int32	DATA offset.
0x34	UInt32	DATA size.
0x38	Byte[8]	Padding.
0x40	End of file header

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.

INFO

The INFO section contains general information about the stream.

Offset	Type	Description
0x00	Char[4]	Section magic. Always INFO in ASCII.
0x04	UInt32	Size of this section in bytes.
0x08	UInt16	Stream info flag. Always 0x4100.
0x0A	UInt16	Padding.
0x0C	Int32	Stream info offset, relative to 0x08 in this structure.
0x10	UInt16	Track info flag. Often not used and therefore set to 0.
0x12	UInt16	Padding.
0x14	Int32	Track info offset, relative to 0x08 in this structure.
0x18	UInt16	Channel info flag. Always 0x0101.
0x1A	UInt16	Padding.
0x1C	Int32	Channel info offset, relative to 0x08 in this structure.

Stream Info

Offset	Type	Description
0x00	Byte	Sound encoding. 0 = PCM8, 1 = PCM16, 2 = DSP ADPCM, 3 = IMA ADPCM.
0x01	Byte	Loop. 1 if it loops.
0x02	Byte	Number of channels.
0x03	Byte	Number of regions.
0x04	UInt32	Sample rate.
0x08	UInt32	Loop start.
0x0C	UInt32	Loop end.
0x10	UInt32	The total number of blocks, including the padded one. If this field is N, S is the size of one block and P is the size of a last padded block, then the size of one channel is (N - 1) * S + P.
0x14	UInt32	Size of one block in bytes.
0x18	UInt32	Size of one block in samples.
0x1C	UInt32	Size of the last block without padding in bytes.
0x20	UInt32	Size of the last block without padding in samples.
0x24	UInt32	Size of the last block with padding in bytes. The last block is always aligned. PCM8 audio is aligned by 0x20 and PCM16 audio is aligned by 0x04.
0x28	UInt32	Size of one channel's seek info for one block, which should be 4, given the History Info should be 4 bytes long in almost all cases.
0x2C	UInt32	SEEK sample interval. The number of samples between each history sample into the SEEK block.
0x30	UInt16	Sample data flag. Always 0x1F00.
0x32	UInt16	Padding.
0x34	Int32	Sample data offset, relative to 0x08 into the DATA block. Offset to the sample data of the first channel.
0x38	UInt16	Size of each region info in bytes. Always 0x100, even when unused.
0x3A	UInt16	Padding.
0x3C	UInt16	Region info flag. Always 0, even when offset is used.
0x3E	UInt16	Padding.
0x40	Int32	Region info offset, relative to 0x08 into the REGN block.
If version ≥ 0.4.0.0
0x44	UInt32	Original loop start.
0x48	UInt32	Original loop end.
If version ≥ 0.5.0.0
0x4C	UInt32	CRC-32 checksum of the whole file with this field set to 0. It is used to match BFSTM and BFSTP when using prefetch.

Track Info

The INFO section links to a reference table which points to this structure. Since v0.2.0.0, this structure is no longer exported and is therefore useless.

Offset	Type	Description
0x00	Byte	Volume.
0x01	Byte	Pan.
0x02	Byte	Span.
0x03	Byte	Flags. ID Type 0x00 Monaural 0x01 Stereo 0x02 Surround 0x03 Dpl2
0x04	UInt16	Global channel index table flag.
0x06	UInt16	Padding.
0x08	Int32	Offset to the global channel index table.

Global Channel Index Table

The Global Channel Index Table is used to bundle the local channel index in the track with the global channel index for the overall stream. It has the following structure:

Offset	Type	Description
0x00	UInt32	C = Count.
0x04	Byte[C]	Items.

Channel Info

The INFO section links to a reference table which points to the following structure. The section flag is set to 0x4102.

Offset	Type	Description
0x00	UInt16	Section flag. Always 0x0300.
0x02	UInt16	Padding.
0x04	Int32	Offset to DSP ADPCM channel info, relative to the start of this structure.

DSP ADPCM Channel 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.

SEEK

The SEEK section is only used for DSP ADPCM audio. It contains information about midstream playback. It contains info about history samples mid-playback in case the game needs to skip to a certain section of the song. The history samples for the first block in each channel is always 0.

Offset	Type	Description
0x00	Char[4]	Section magic. Always SEEK in ASCII.
0x04	UInt32	Size of this section in bytes (S).
0x08	HistoryInfo[Number of blocks][Number of channels]	History information.

History Info:

Offset	Type	Description
0x00	Int16	History sample 1. The index to the sample in PCM16 data is the Seek Interval * Block Number - 1.
0x02	Int16	History sample 2. The index to the sample in PCM16 data is the Seek Interval * Block Number - 2.

REGN

The REGN section devides the data into different regions. It starts with the following structure:

Offset	Type	Description
0x00	Char[4]	Section magic. Always REGN in ASCII.
0x04	UInt32	Size of this section in bytes.

Region

The number of regions is specified in the stream info into the INFO block. Each entry consists of the following:

Offset	Type	Description
0x00	UInt32	Start of the region in samples.
0x04	UInt32	End of the region in samples.

After comes 16 entries, representing up to 16 channel loop context. Unused entries are filled with 0. Each entry has the following structure:

Offset	Type	Description
0x00	UInt16	Loop Pred Scale.
0x02	UInt16	Loop Yn 1.
0x04	UInt16	Loop Yn 2.

0x98 bytes of padding are placed to align each region to be 0x100 bytes long.

DATA

The DATA section holds all the data for the stream. It has the following structure:

Offset	Type	Description
0x00	Char[4]	Section magic. Always DATA in ASCII.
0x04	UInt32	Size of this section in bytes (S).
0x08	Byte[S - 8]	Sound data.

Version List

Version	Found in
0.3.0.0	Kirby & the Rainbow Curse Mario Kart 8 Mario & Sonic at the Sochi 2014 Olympic Winter Games Splatoon Super Mario 3D World
0.4.0.0	1-2-Switch ARMS Captain Toad: Treasure Tracker (Nintendo Switch) Mario Kart 8 Deluxe Mario Kart 8 Deluxe (S00018080-R00018076-A00000000 Prototype) Mario Tennis: Ultra Smash Super Mario Maker The Legend of Zelda: Breath of the Wild (Nintendo Switch)
0.5.0.0	Splatoon 2
0.6.1.0	Game Builder Garage Mario Tennis Aces 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 Pikmin 3 Deluxe Splatoon 2 Super Mario Odyssey Super Mario Party Sushi Striker: The Way of Sushido (Nintendo Switch)
0.6.3.0	Clubhouse Games: 51 Worldwide Classics Dr Kawashima's Brain Training for Nintendo Switch Mario Golf: Super Rush Momotaro Dentetsu: Showa, Heisei, Reiwa mo Teiban! PAC-MAN 99 Paper Mario: The Origami King Super Kirby Clash Super Mario 3D World + Bowser's Fury Tetris 99 The Legend Of Zelda: Link's Awakening
0.6.4.0	Big Brain Academy: Brain vs. Brain Everybody 1-2-Switch! F-ZERO 99 Mario Party Superstars Nintendo World Championships: NES Edition
2.0.0.0	Kirby Fighters 2
2.0.1.0	Kirby's Dream Buffet

Tools

The following tools can handle BFSTM files:

• BrawlBox, by Kryal & BlackJax
• Citric-Composer, by Gota7
• Wexos's Toolbox, by Wexos