BNTX (File Format)

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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
4.1.0

Tools

The following tools can handle BNTX files:

  • (none)
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