RKC Files (Revolution Kart Competition) are files downloaded by Mario Kart Wii using the WC24 download engine. The RKC file contains data and a U8 file with a new KMP for the competition. The RKC file is part of the DISTMAP.BIN file, which is stored inside the wc24dl.vff file in the savegame.

The maximum file size for a RKC file in the unmodified game is 20480 bytes. It might be possible to change the maximum size by finding the call to malloc() which allocates the space for the RKC data in the game's memory.

File Format

The RKC files contain multiple headers, they are all explained here.

RKCT

The RKCT header, or the main header, is 0x10 bytes long:

Offset	Type	Description
0x00	String	File magic. Always RKCT in ASCII.
0x04	UInt32	Length of the data in bytes.
0x08	UInt32	Length of all file headers (offset to the beginning of the U8 file).
0x0C	UInt32	Unknown, always 0x640. Maybe a version number?

RKCO

The RKCO Header contains all information for the competition. Stuff like Course ID, CommonObj that gets loaded and other information. The header is 0x3C bytes long:

Offset	Type	Description
0x00	String	Section magic. Always RKCO in ASCII.
0x04	UInt16	Game mode.
0x06	Byte	Course ID.
0x07	Byte	Engine class. 0: 50cc, 1: 100cc, 2: 150cc, 3: battle.
0x08	Byte	Amount of laps (laps, so triggered with checkpoints, not scores).
0x09	Byte	Padding.
0x0A	UInt16	Vehicle restriction. 0: karts only, 1: bikes only, 2: no restriction.
0x0C	UInt16	Camera angle. 3: normal camera, 7: camera from above.
0x0E	UInt16	Minimap object. Defines an object to be shown on the minimap.
0x10	UInt16	Always empty, but read by the game.
0x12	UInt16	Always empty, but read by the game.
0x14	UInt16	Cannon flag. If a track has no cannon, this is set to 0. If a track has a cannon and its setting is 0xFFFF, it is set to 0, too. Otherwise, it is set to the value of the cannon setting.
0x16	UInt16	Amount of CPU players.
0x18	Byte[22]	Driver and vehicle settings for CPU players. First byte driver, second byte vehicle. 0xFF for random driver / vehicle or unused slots.
0x2E	Byte	Controller. 0x00 for free choice, 0x01 for Wii-Wheel only.
0x2F	Byte	Padding.
0x30	UInt16	Common object files to load. Bit field for the different files.
0x32	UInt16	Score (amount of gates, amount of coins, etc).
0x34	Byte	Intro settings. Between 0x00 and 0x03: 0x00: no intro video 0x01: intro with Battle music 0x02: intro with VS Race music 0x03: Intro with Boss music
0x35	Byte	Padding.
0x36	UInt16	Unknown, either 18000 (0x4650) for tracks with laps, 36000 (0x8CA0) for tracks with a score, or 54000 (0xD2F0), exclusively used for the Giant Pokey competition.
0x38	UInt16	Padding.
0x3A	UInt16	This seems to be a checksum of the header.

Game Modes

Here are the known game modes:

Value	Description
0x00	Time Trial. No position tracker. 3 Mushrooms, multiple KTPT, MSPT.
0x01	VS Race. Position tracker, single KTPT (player last), CPUs, continuing racing after finish.
0x03	Many different objects.
0x04	Spiky Topmen, big Pokey.
0x05	Coins (single coin, leafpile coin).
0x06	Star gates.
0x07	Hit CPUs with blue shell, red shell, green shell, Fake item box, banana, or bob-omb to win (unused), No Position tracker, single KTPT (player first) or multiple, CPUs, MSPT (number of CPUs).
0x0B	Battle. No Position tracker, single KTPT (player first) or multiple, CPUs, MSPT (number of CPUs).
0x0C	Battle. Position tracker, single KTPT (player first) or multiple, CPUs, MSPT (number of CPUs).
0x0E	Perform drifts to win, CPUs drifts count too (unused). No position tracker, single KTPT (player first) or multiple, CPUs, MSPT (number of CPUs).

Note that when there is no position tracker, the game always act like you're 12th.

In game mode 0x03, many different objects will give you a point when you destroy, hit or activate them. The objects are:

and probably some more.

There are a few more game modes (the ones which do not appear in the list of game modes above), but their meaning and usage is unknown.

RKCS

This is the part of a RKC file that contains the actual data. It only contains a YAZ0 compressed U8 file with a KMP file and some object files which are neither in the course, the competition bases or in one of the CommonObj files.

This U8 file must contain the folders AIParam and ItemSlotTable, but both of them may be empty if you do not want to modify the AI settings or the items.

Replacing and ripping RKC files

NOTE: The data blocks which were previously known as "RSF Files" (this name was invented by khacker35000vr to name unknown data groups) are not part of the actual competition. If you extract the VFF file and not just open it in a hex editor, you can see that there is no data after the RKC file. The "trash data" (RSF) in the VFF file after the RKC data is just random data from the previous competition, because Nintendo just copies the new RKC file to the specific offset and does not clear the rest of the file. So, when a new competition is smaller than the old one, those trash bytes stay in the file, even though they are not needed.

Replacing

Search the RKC file in the VFF File.
Copy and paste (overwrite old data) the data of your custom RKC file at the good offset.
If the new RKC file is larger than the older one this may not work. At the moment there is no tool to create larger VFF files.

Ripping

Use Riivolution along with the savegame XML when a competition is in progress, or copy your savegame to SD with tools like Savegame Manager GX.
Extract the wc24dl.vff with "vffdump.py".
Open the file "DISTMAP.BIN" in a hex editor and search for "RKCT".
Check the size and copy that amount of bytes to a new file (RKC).

Misc.

Custom tournaments are able to be made, and can be added to Leseratte's competition system for Wiimmfi.
All downloaded contents (competition and other players' ghost data) for Mario Kart Wii are saved in wc24dl.vff.

Tools

The following tools can handle RKC files:

RKC Editor, by Leseratte
Wexos's Toolbox, by Wexos

A kaitai format description file can be found on this GitHub repository.

RKC (File Format)

Contents