IFO (stands for InFOrmation) is a type of DVD-Video file that stores information about chapters, subtitles and audio tracks.
An IFO file is one of three types of files that are used on DVDs. It contains important navigational information, such as where a video chapter begins, and where audio and subtitle streams exist within the movie (VOB) file.[1] IFO files are not encrypted.
Other DVD file types include VOB and BUP.