This is a centralized place for the documentation and other discoveries about the internal working of Kingdom Hearts games.

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Kingdom Hearts Birth By Sleep - ARC format

The ARC format (presumability a int16en of Archive) is a container of files with a dependency system feature to other files in a BBSA archive.

File format

The RESERVED fields are used by BBS engine to store a point32er to the data.

Offset Type Description
0x0 int32 File identifier, 0x435241
0x4 int16 Version, always 1
0x6 int16 Entry count
0x8 int32 RESERVED
0xc int32 RESERVED

Right after the header, an array of entry is found.


An entry can represents either a file contained in the archive or a file the archive depends on.

Offset Type Description
0x0 int32 Directory hash
0x4 int32 Offset
0x8 int32 Length
0xc int32 RESERVED
0x10 char[16] File name

When the file exists in the archive, Directory hash is 0.

When the entry is a link to anotehr file, Directory hash has a value and Lenght is 0 while Offset value is ignored.

Additional info

Apparently the file arc/menu/01_race.arc from Birth By Sleep is corrupt and unreadable. It is unknown if the remastered actually uses that file; and if yes, how.