PAC File format specification Known filename extensions: .pac The file format is used by Capcom. The file is read in little endian mode. The file begins with a 4 byte long integer specifying the number of files in it. Following that is just that many 8 byte long records for each file in the archive. The first 4 bytes in each record is the file offset in the archive while the next 4 is the size of the file. There are no filenames provided by the format. Written by henke37 2011. Greets to lowlines for the help in figuring out the file format.