To understand the role of these files, one must first understand the "Fat" and "Dat" designation. In the context of the Dunia Engine 2 (the proprietary engine powering Far Cry 3), .dat files generally serve as archives—akin to .zip or .rar files—containing raw data that the engine calls upon during runtime. The .fat file, acting as a header or table of contents, accompanies the archive. While the .dat holds the actual audio assets—the voice lines, barks, radio chatter, and ambient dialogue—the .fat likely contains the metadata: the offsets, file sizes, and directory structures required for the engine to locate a specific sound file instantly within a massive archive.
The specific filename soundenglish denotes these as the localization packages for the English language. In a AAA title like Far Cry 3, audio is not stored globally; it is compartmentalized by language to allow for regional distribution and to manage memory usage. A player playing in French does not need the gigabytes of English voice data loaded into memory. Therefore, soundenglish.dat is a self-contained universe of linguistic data, holding the iconic performances of characters like Vaas Montenegro and Jason Brody.
Hex dump of one entry from soundenglish.fat (PC version, offset 0x1A2B0): far cry 3 soundenglishdat and soundenglishfat files
50 67 2A 00 C0 15 00 00 00 00 00 00 05 00 00 00
FF FF FF FF C0 5D 01 00 01 00 00 00 00 00 00 00
Interpretation:
Filename at that offset: "music/combat/combat_stealth_01.mp3". To understand the role of these files, one
Before you re-download the entire game (which is 7–10 GB), try these solutions in order.
"Data error (cyclic redundancy check)."
Translation: Your hard drive or the source media has physical damage or corruption. This is the scariest error, often pointing to failing hardware.