.AVI files are one of the oldest and most compatible video file formats. Many different codecs can be used with an .AVI file, which means that this format has more flexibility in choosing a balance between quality and size. The container file holds the metadata and compressed video data which is encoded using the codec. The container format is also more generally called “the format”, and is reflected in the file’s extension. Common container formats include .AVI to .MP4, and .MOV. Container formats can be paired with different codecs that influence what devices and programs the file will be compatible with.