Burst Cutting Area Data
In computing, the burst cutting area (BCA) or narrow burst cutting area (NBCA) refers to the circular area near the center of a DVD, HD DVD or Blu-ray Disc, where a barcode can be written for additional information such as ID codes, manufacturing information, and serial numbers. The BCA can be written during mastering and will be common for all discs from that master or, more usually, will be written using a YAG laser to "cut" the barcode into the aluminum reflective layer of the finished disc, potentially adding a unique barcode to each manufactured disc.
Nintendo Wii and BCA data
The Wii's optical game media feature BCA. This has been implemented to presumably make it impossible for home users to create discs that carry BCA, hence preventing piracy. As of now (2011-08-15) there is only one game that uses BCA data for copy protection: "New Super Mario Bros. Wii" (i.e. the game cannot be played from a self-burned optical disc without being patched beforehand).
WODE and BCA data
WODE is able to emulate BCA to the Wii using files that contain the BCA code.
The naming convention for files containing BCA data is:
Game.iso -> Game.bca
Game.wbfs -> Game.bca
Obtaining BCA data
WODE automatically rips BCA data from a disc when using "Rip all" or "Rip No Update" and places it alongside the target iso/wbfs-file.
If you need to acquire BCA data for a game you've already ripped, there's also the option "Rip BCA Only" available. Make sure that the iso/wbfs-file has the same name afterwards.
Manually created BCA files are NOT compatible with riivolution (1)