.avi File — Audio Video Interleave

AVI (Audio Video Interleave) is a multimedia container format introduced by Microsoft in 1992 as part of its Video for Windows technology. AVI files interleave audio and video data in alternating chunks within a RIFF (Resource Interchange File Format) container, allowing synchronized playback of both streams. The format is codec-agnostic — it can contain video compressed with virtually any codec (DivX, XviD, MPEG-4, H.264, and even uncompressed) paired with audio in MP3, PCM, AC3, or other formats. AVI was the dominant video format on Windows PCs throughout the 1990s and 2000s, particularly during the DivX/XviD era of video sharing. The format has significant limitations compared to modern containers: it lacks native support for variable frame rates, B-frame compression, embedded subtitles (beyond basic text), chapter markers, and reliable streaming. AVI also has a practical file size limit of 2 GB without OpenDML extensions. Despite these limitations, AVI remains widely encountered in legacy video collections and is still used by some capture devices and editing workflows that value its simplicity and universal compatibility.