Audio Video Interleave, a Microsoft multimedia container format introduced in 1992 as part of its Video for Windows technology. AVI files can hold audio and video data in a standard container and provide synchronous video/audio replay. Most AVI files also use the OpenDML file format extensions, forming AVI 2.0 files.
Some consider AVI outdated, as there are significant overheads using it with popular MPEG-4 codecs that seemingly unduly increase file sizes. Despite that, it remains popular among file-sharing communities, probably due to its high compatibility with existing video editing and playback software, such as Windows Media Player.