655 Audio/Video Interleaved Format AVI (Generic) Audio, Video Full Audio/Video Interleaved Format (AVI) is a chunk-based video format developed by Microsoft, based on the generic Resource Interchange File Format (RIFF) specification developed by Microsoft and IBM. Structurally, an AVI file is composed of a number of chunks, each comprising a four character code chunk identifier, the chunk size, and the chunk data. It comprises a RIFF header with an AVI data type identifier, followed by a series of chunks. Every file must include two List chunks. The first List chunk is the main AVI header chunk, which contain one or more Stream Header chunks, one for each data stream, describing the format of the data streams. The second LIST chunk is the ‘movi’ chunk, which contains the actual data for the audio and video data streams. Other optional chunks are also allowed. The format supports a wide variety of compressed and uncompressed video encodings, but all audio streams are stored in Microsoft’s Waveform Audio format. Binary Little-endian (Intel) 1 Digital Preservation Department / The National Archives 11 Mar 2005 08/2023 (v.113) - Added priority over fmt/1886 (Resource Interchange Format (RIFF)) and simplified internal signature to reduce identification tool processing time. Submitted by Preservica and New York Public Libraries. 14 Aug 2023 fmt/5 PUID public.avi Apple Uniform Type Identifier video/x-msvideo MIME avi File extension 51 AVI BOF: 'RIFF' and after four bytes 'AVI' 1 Absolute from BOF 0 0 52494646{4}41564920 Has priority over 2741 Resource Interchange File Format (RIFF)