Audio Video Interleave (AVI) is a wrapper format audio and video created by Microsoft which official extension is .avi. It is one of the most popular formats in the world, recognized natively by most versions of Windows and all the DVD players that are compatible with the DivX codec.
AVI is a form of association interlace video and audio, each in their respective proportions and peculiarities. It is a space in which it stores information. The AVI can contain a video track encoded in any codec in the same age and you can associate an MP3 audio.