IFF
- This article is about the generic IFF metaformat. For the IFF image format, see ILBM.
IFF (Interchange File Format) is a general-purpose binary file format introduced by Electronic Arts on the Commodore Amiga computer in 1985. It is sometimes known as IFF 85.
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Format details
An IFF file is composed of elements called "chunks". Each chunk consists of a 4-byte type identifier (represented by four ASCII characters), a 4-byte length, and the chunk's payload data. Some types of chunks contain a sequence of nested chunks. Multi-byte numeric values are big-endian.
IFF defines a number of standard chunks types. Additional types are invented as needed by IFF-based formats.
Of particular significance is chunk type FORM. Most IFF-based files are formatted as a single FORM chunk. A FORM chunk's data contains a four-byte "FORM type" code, indicating the data type, followed by a sequence of nested chunks.
An IFF-based format whose FORM type is xxxx might be referred to as "FORM xxxx". FORM types may also be used as filename extensions.
Identification
Most IFF files begin with the ASCII characters "FORM". The file type is then indicated by the 4-byte ASCII code beginning at offset 8.
There are also aggregate formats that begin with "LIST" or "CAT ".
IFF-based formats
Formats based on IFF include:
See Category:IFF based file formats for more.
Variant formats
Some other formats are largely or heavily influenced by the IFF standard, but are not compatible. These include, for example:
- Erlang BEAM compiled modules: Uses 4 byte alignment instead of 2 byte, and the root chunk has a different ID (
FOR1instead ofFORM) - Microsoft's RIFF and RIFX formats are based on IFF (RIFF uses little-endian byte order instead, and the root chunk is called
RIFFinstead ofFORM) - Apple's AIFF and AIFC formats are similar to IFF/RIFF as well
- Maya IFF
