RIFFformatted

RIFFformatted refers to data organized according to the RIFF container format, a general multimedia wrapper introduced in the 1990s by Microsoft and IBM. RIFF uses a chunk-based architecture where data is stored in labeled blocks called chunks. Each chunk comprises a four-character identifier (FourCC), a 32-bit little-endian size, and payload data. The file starts with the ASCII "RIFF," followed by the file size and a form type that indicates the kind of content, such as "WAVE" for audio or "AVI " (with a trailing space) for video.

After the form type, the file contains chunks in sequence. A chunk has a 4-byte ID, a 4-byte size, and payload data. Some chunks may be LIST chunks, which group subchunks and carry a 4-byte list type. All chunks are aligned to even sizes, with a padding byte added if a payload length is odd. This layout supports random access, straightforward parsing, and easy extension by introducing new chunk types without breaking existing data.

Common examples of RIFFformatted files include WAV, which uses the RIFF container with form type "WAVE" to encode audio data; AVI, which uses "AVI " for video data; and WEBP, a raster image format that employs a RIFF container with form type "WEBP." The approach has influenced other container formats and remains widely supported across platforms.

Advantages of RIFFformatted data include simplicity, flexibility, and efficient random access to individual chunks and metadata. Limitations include overhead from chunk headers, potential compatibility issues with nonstandard or nested chunks, and reliance on little-endian encoding. RIFF remains most suited to multimedia storage and editing rather than streaming with rigid, byte-for-byte semantics.

See also RIFF, WAV, AVI, WEBP.