The Resource Interchange File Format (RIFF) is a generic meta-format for storing data in tagged chunks. It was introduced in 1991 by Microsoft and IBM. It is a clone of Electronic Arts's Interchange File Format, introduced in 1985, the only difference being that multi-byte integers are in little-endian format, native to the 80x86 processor series used in IBM PCs, rather than the big-endian format native to the 68k processor series used in Amiga and Apple Macintosh computers, where IFF files were heavily used.

The Microsoft implementation is mostly known through file formats like AVI, ANI and WAV, which use the RIFF meta-format as their basis.

RIFF files consist entirely of "chunks". The overall format is identical to IFF, except for the endianness as previously stated, and the different meaning of the chunk names.

All chunks have the following format:

• 4 bytes: an ASCII identifier for this chunk, e.g. "fmt " or "data".
• 4 bytes: an unsigned, little-endian 32-bit integer with the length of this chunk (except this field itself and the chunk identifier).
• variable-sized field: the chunk data itself, of the size given in the previous field.
• a pad byte, if the chunk's length is not even.

Two chunk identifiers, "RIFF" and "LIST", introduce a chunk that can contain subchunks. Their chunk data, after the identifier and length, has the following format:

• 4 bytes: an ASCII identifier for this particular chunk (in the case of the RIFF chunk: for the entire file, such as "AVI " or "WAVE").
• rest of data: subchunks.

The file itself consists of one RIFF chunk, which then can contain further subchunks.

More information about the format can be found in the Interchange File Format article.

See also

• IFF
• AIFF
• FourCC

External links

• Resource Interchange File Format Services
• RIFF AVI file reference
• Reading WAVE files
• DirectMusic file format
• Multimedia Registration Kit

Computer file formats

Resource Interchange File Format | Resource File Interchange Format | RIFF | RIFF