BNTX (File Format)

BNTX (Binary NX TeXture) is a file format used on the Nintendo Switch. It contains one or more images, and can also embedded into other file formats such as BFRES, BFFNT and PTCL.

File Format

Header

The file format starts with the following header:

Offset	Type	Description
0x00	Char[8]	File magic. Always BNTX\0\0\0\0 in ASCII, or 42 4E 54 58 00 00 00 00.
0x08	UInt32	File version.
0x0C	UInt16	Byte-order-mark. FE FF for big endian, FF FE for little endian.
0x0E	Byte	Alignment shift. 2 raised by this value is the alignment required by this file when loaded into memory.
0x0F	Byte	Target address size. Size of a pointer in bits, thus 64.
0x10	UInt32	File name offset. Points directly to the string, and not to the length unlike all other strings.
0x14	UInt16	A flag which is only used on runtime. One bit sets wether the file is relocated.
0x16	UInt16	Offset to the first section.
0x18	UInt32	Relocation table offset.
0x1C	UInt32	Size of the file in bytes.

Texture Container

The texture container stores general data about the file.

Offset	Type	Description
0x00	String	Target platform. "NX " for Switch, "Gen " for computer
0x04	Int32	N = Number of textures.
0x08	Int64	Texture table offset. Points to an Int64[N] which points to the textures.
0x10	Int64	Texture data offset. Points to the texture data.
0x18	Int64	Texture DICT offset. Points to a dictionary containing the texture names.
0x20	Int64	Texture memory pool offset.
0x28	Int64	Current memory pool pointer (set on runtime).
0x30	UInt32	Base memory pool offset (set on runtime).
0x34	Byte[4]	Reserved.

Texture

Each texture contains texture data for all mipmaps. The texture data is swizzled when used on a Switch.

Offset	Type	Description
0x00	Char[4]	Section magic. Always BRTI in ASCII.
0x04	UInt32	Next section offset.
0x08	UInt32	Size of this section in bytes.
0x0C	Byte[4]	Reserved.
0x10	Byte	Flag. xxxx ABCD. A: res texture B: sparse residency C: sparse binding D: specify texture layout
0x11	Byte	Image storage dimension. Value Dimension 0x00 Undefined 0x01 1D 0x02 2D 0x03 3D
0x12	UInt16	Tile mode. Optimal = 0 (swizzled), Linear = 1 (not swizzled).
0x14	UInt16	Swizzle value.
0x16	UInt16	Number of mipmaps, including the main level image.
0x18	UInt16	Number of multi samples.
0x1A	Byte[2]	Reserved.
0x1C	UInt32	Image format.
0x20	UInt32	GPU access flag. Sets the access type of the GPU.
0x24	Int32	Width of texture in pixels.
0x28	Int32	Height of texture in pixels.
0x2C	Int32	Depth of texture in pixels. 1 if texture is 2D.
0x30	UInt32	Array length, number of textures in the array. 1 if texture is not an array texture.
0x34	Byte[8]	Texture layout. Contains the block height shift, which is used for the swizzling algorithm.
0x3C	Byte[20]	Reserved.
0x50	UInt32	The total size of all mipmap data.
0x54	UInt32	Texture data alignment. Always 0x200.
0x58	Byte[4]	Channel sources for the red, green, blue and alpha channels respectively. Value Channel Source 0x00 Zero 0x01 One 0x02 Red 0x03 Green 0x04 Blue 0x05 Alpha
0x5C	Byte	Texture dimension. Value Dimension 0x00 1D 0x01 2D 0x02 3D 0x03 Cube 0x04 1D array 0x05 2D array 0x06 2D multisample 0x07 2D multisample array 0x08 Cube array
0x5D	Byte[3]	Reserved.
0x60	Int64	Name offset. Points to this texture name.
0x68	Int64	Texture container offset.
0x70	Int64	Image data table offset. Points to an array of Int64 which points to the different levels of the textures.
0x78	Int64	User data offset.
0x80	Int64	Texture pointer. Points to 0x100 unknown bytes, presumably used on runtime.
0x88	Int64	Texture view pointer. Points to 0x100 unknown bytes, presumably used on runtime.
0x90	Int64	Descriptor slot data offset. Unknown data, presumably used on runtime.
0x98	Int64	User data dictionary offset. Points to a dictionary containing the user data names.

Texture Data

The texture data starts with a header marker which presumably is not used. The structure, which is 0x10 bytes long, is placed so that the texture data is aligned by the alignment specified in the header. All texture data follows after the header. It has the following structure:

Offset	Type	Description
0x00	Char[4]	Section magic. Always BRTD in ASCII.
0x04	UInt32	Next section offset.
0x08	UInt32	Size of this section in bytes.
0x0C	Byte[4]	Reserved.

String Table

The string table is a table where all strings are stored. Each string has first the length written, which is a 16-bit integer, and then the string is stored as a null-terminated string. The string length does not include the null byte, and the 16-bit string length value is always aligned by 2. The string sorting algorithm is unknown.

Offset	Type	Description
0x00	Char[4]	Section magic. Always _STR in ASCII.
0x04	UInt32	Next section offset.
0x08	UInt32	Size of this section in bytes.
0x0C	Byte[4]	Reserved.
0x10	Int32	Number of strings stored in the string table. The first string is always an empty string ("") and is not included in this count.

Dictionary

A dictionary (sometimes known as DICT) is a common structure used in many Nintendo formats such as BFRES and BNTX. It is used for fast name look-up, in order to find a specific array item by its name. It starts with the following structure:

Offset	Type	Description
0x00	Char[4]	Section magic. Always _DIC in ASCII. Note that in BFRES this magic is set to 00 00 00 00, most likely due to an export error.
0x04	Int32	Number of entries. This does not include the root entry.

After, the entries are specified. The root entry follows first, then all other entries are stored. Each entry has the following structure:

Offset	Type	Description
0x00	Int32	Ref bit.
0x04	UInt16[2]	Child node indices. First the left node, then the right node.
0x08	Int64	Key offset, which points to the key name this entry stores.

User Data

User data is a common structure used in many Nintendo formats such as BFRES and BNTX. It allows game designers to store generic data into different files, in order to be used by the game. The data can be used for anything, and is not used by the actual data parser. Each entry has the following structure:

Offset	Type	Description
0x00	Int64	Name offset. Points to the name of this user data entry.
0x08	Int64	Data offset. Points to the actual data. What the data actually is depends on the data type.
0x10	Int32	Number of data entries.
0x14	Byte	Data type. Value Data Type 0x00 Int32 0x01 Float 0x02 String 0x03 Byte
0x15	Byte[43]	Reserved.

Relocation Table

Offset	Type	Description
0x00	Char[4]	Section magic. Always _RLT in ASCII.
0x04	UInt32	Table offset. The offset where this table starts.
0x08	Int32	Number of sections.
0x0C	Byte[4]	Padding.

Offset	Type	Description
0x00	Int64	Section pointer, set on runtime.
0x08	UInt32	Section offset.
0x0C	UInt32	Section size.
0x10	UInt32	Entry ID.
0x14	UInt32	Number of entries.

Offset	Type	Description
0x00	UInt32	Entry offset.
0x04	UInt16	Array count.
0x06	Byte	Offset count.
0x07	Byte	Padding size.

Version List

Version	Found in
4.0.0	1-2-Switch ARMS Captain Toad: Treasure Tracker (Nintendo Switch) Fire Emblem: Three Houses Game Builder Garage Mario Golf: Super Rush Mario Kart 8 Deluxe Mario Kart 8 Deluxe (S00018080-R00018076-A00000000 Prototype) Mario Party Superstars Mario Tennis Aces Momotaro Dentetsu: Showa, Heisei, Reiwa mo Teiban! New Super Mario Bros. U Deluxe 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 Nintendo Switch System BIOS (1.0.0 – 8.1.0) Paper Mario: The Origami King Pikmin 3 Deluxe Pokémon: Let's Go, Eevee! Pokémon: Let's Go, Pikachu! Pokémon Shield Pokémon Sword Ring Fit Adventure Splatoon 2 Super Kirby Clash Super Mario Maker 2 Super Mario Odyssey Super Mario Party Super Smash Bros. Ultimate Sushi Striker: The Way of Sushido (Nintendo Switch) Tetris 99 The Legend of Zelda: Breath of the Wild (Nintendo Switch) The Legend of Zelda: Echoes of Wisdom Tokyo Mirage Sessions ♯FE Encore
4.1.0	Animal Crossing: New Horizons Big Brain Academy: Brain vs. Brain Clubhouse Games: 51 Worldwide Classics Dr Kawashima's Brain Training for Nintendo Switch Everybody 1-2-Switch! F-ZERO 99 Mario Golf: Super Rush Mario Party Superstars Momotaro Dentetsu: Showa, Heisei, Reiwa mo Teiban! Nintendo Switch Sports Nintendo Switch System BIOS (8.0.1 – 8.1.0) Nintendo World Championships: NES Edition PAC-MAN 99 Paper Mario: The Origami King Paper Mario: The Thousand-Year Door (Nintendo Switch) Pokémon Legends: Arceus Pokémon Scarlet Pokémon Violet Splatoon 3 Super Mario 3D World + Bowser's Fury Super Mario 3D All-Stars Super Mario Bros. Wonder The Legend Of Zelda: Link's Awakening The Legend of Zelda: Tears of the Kingdom WarioWare: Get It Together! WarioWare: Move It!

Tools

The following tools can handle BNTX files:

• (none)