Interchange File Format
| Developed by | Electronic Arts, Commodore/Amiga |
|---|---|
| Initial release | 1985 |
| Type of format | Digital container format |
Interchange File Format (IFF), is a generic container file format originally introduced by the Electronic Arts company in 1985 (in cooperation with Commodore/Amiga) in order to facilitate transfer of data between software produced by different companies.
IFF files do not have any standard extension. On many systems that generate IFF files, file extensions are not important (the OS stores file format metadata separately from the file name). An .iff extension is commonly used for ILBM format files, which use the IFF container format.
Resource Interchange File Format is a format developed by Microsoft and IBM in 1991 that is based on IFF, except the byte order has been changed to little-endian to match the x86 processor architecture. Apple Computer's AIFF is a big-endian audio file format developed from IFF. The TIFF image file format is unrelated.
An IFF file is built up from chunks. Each chunk begins with what the specification calls a "Type ID" (what the Macintosh called an OSType, and Windows developers might call a FourCC). This is followed by a 32-bit signed integer (all integers in IFF file structure are big-endian) specifying the size of the following data (the chunk content) in bytes. Because the specification includes explicit lengths for each chunk, it is possible for a parser to skip over chunks that it either can't or doesn't care to process.
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