BIN (File Format)
BIN is a file format used in Mario Kart 8 to store binary lookup tables, like item probabilities at distances to the lead racer, the distances for this themselves, course information, audio information, controller mappings (possibly), kart body/tire/glider settings, engine statistics or (in Mario Kart 8 Deluxe) software racer skill (AI) and user interface configuration.
BIN files are found in the /content/common/mush (Wii U / Switch) directory.
Format
Each BIN file consists of several sections as defined in the file header. The sections have a unique identifier, which the game uses to determine how to parse the data available after the section header.
Mario Kart 8 (Wii U) stores the files in big endian, Mario Kart 8 Deluxe in little endian.
The format is similar to the one used in Mario Kart 7, though it strips a lot of textual data describing the entries of the groups, which makes giving meaning to the values of the elements harder, though many elements are simply evolved or even ported from Mario Kart 7.
File Header
Each BIN file starts with a main header which provides information about the available sections in the file.
| Offset | Size | Type | Description |
|---|---|---|---|
| 0x00 | 4 | UInt32 | File identifier. Takes the form of a 4 character ASCII string acronym of the file's purpose. |
| 0x04 | 4 | Int32 | File size in bytes. Sometimes slightly off from the real file size, unclear why this is the case. |
| 0x08 | 2 | Int16 | Number of sections following the header. |
| 0x0A | 2 | Int16 | Header size. Required to compute absolute offsets to the sections (s. below). |
| 0x0C | 4 | Int32 | Version number. Always 1000. Can be used to determine endianness. |
| 0x10 | 4 * Number of sections | Int32[numberOfSections] | Offsets to the sections, relative to the end of the header. |
Section
A section begins with a section header which stores a unique identifier and some parameters required to parse the following section data. The start of each section is aligned by 4 bytes.
| Offset | Size | Type | Description |
|---|---|---|---|
| 0x00 | 4 | UInt32 | Section identifier. Takes the form of a 4 character ASCII string acronym of the section's purpose. |
| 0x04 | 2 | Int16 | Count parameter. Typically used to specify the number of elements in the data arrays (s. next parameter). |
| 0x06 | 2 | Int16 | Repeat parameter. Typically used to specify the number of data arrays in this section. |
| if Mario Kart 8 | |||
| 0x08 | 4 | Int32 | Additional parameter. Can be used to assume the type of data following, but this is often not correct. |
| if Mario Kart 8 Deluxe | |||
| 0x08 | 4 | Int32 | Unknown parameter. |
| 0x0C | 4 | Int32 | Additional parameter. Can be used to assume the type of data following, but this is often not correct. |
Section Data
Depending on the Section identifier, the game knows how to interprete the data following in the section, with the help of the common parameters given in the section header. It can be assumed that the data is directly copied into console memory and then casted to structures. Thus, it is required to know which Section identifier maps to which structure.
However, even without knowing these structures, several generic section data formats are seen, which are described in the following. This list is not exhaustive.
3-dimensional Dword Array
The section data consists of a 3-dimensional array of 4-byte integer or float values. The length of each dimension is given in the section header, except for the last dimension, which has to be computed manually if the resulting structure is not known:
| Dimension | Length |
|---|---|
| 0 | Repeat parameter given in section header. |
| 1 | Count parameter given in section header. |
| 2 | section data size / Repeat / Count / sizeof(int) |
2-dimensional String Array
The data in this section are arrays of offsets pointing to 0-terminated strings following them. The number of string arrays is given in the Repeat and the length of each array in the Count parameter of the section header. Each array is stored as follows:
| Size | Type | Description |
|---|---|---|
| 4 * elementCount | Int32[elementCount] | String offsets, relative to the end of the last offset. E.g., the first offset is always 0. |
| - | String[elementCount] | Strings, 0-terminated, pointed to by the preceeding offsets. |
2-dimensional Indexed String Array
The data in this section are arrays of increasing indices and offsets pointing to 0-terminated strings following them. The number of string arrays is given in the Repeat and the length of each array in the Count parameter of the section header. Each array is stored as follows:
| Size | Type | Description |
|---|---|---|
| 8 * elementCount | Entry[elementCount] | String entries, each stored as follows: |
| 1 | Byte | Index of this string. Starts at 0 and increased by 1. |
| 3 | - | Padding. |
| 4 | Int32 | String offset, relative to the end of the last offset. E.g., the first offset is always 0. |
| - | String[elementCount] | Strings, 0-terminated, pointed to by the preceeding offsets. |
Tools
The following tools can handle BIN files:
- BIN Editor, by Ray Koopa: can visualize and modify data stored in Item.bin and Performance.bin files
- NintenTools.MarioKart8, by Ray Koopa: provides a .NET library to access BIN data