AVI is a multimedia container that is very popular among PC and Mac users. The format was developed by Microsoft in 1992. Usually AVI is used as a video format but unlike other formats of that time, AVI may contain both audio and video data compressed with a use of different combinations of codecs. More often such video codecs as DivX and XVID are used with .avi files. For audio playback such codecs as MP3, AC3 and PCM are used. It is possible to play AVI files with Windows Media Player or other similar programs.

This format was originally intended for voice compression and is able to change the bit rates of encoded audio data. AMR is actively used for encoding and decoding voice while its being transmitted over network channels. The format allows one to consider network capacity and adapt it to channel loads. Due to this, the voice quality is practically undiminished.