In a nutshell, AVI is one of the most popular video file formats. But there’s more to it than might seem at the first look – AVI (or Audio Video Interleave),is actually a multimedia “container format”. AVI files can contain both audio and video data (multiple tracks supported) in a file container that allows synchronous audio-with-video playback. The audio/video can be encoded with a various diverse codecs and quality.

The AVI format was introduced by Microsoft in November 1992 as part of its Video for Windows technology. Most AVI files also use the file format extensions developed by the Matrox OpenDML group in February 1996. These files are supported by Microsoft, and are unofficially called “AVI 2.0”.

While the AVI format is very popular, it’s not the best format for large videos. When AVI is used to store video in popular MPEG-4 codecs (e.g. Xvid and DivX) the files turn out bloated and larger than necessary. Other container formats, like Ogg and MP4, are more efficient.