What is IFO file?

IFO information is a video title set (VTS). When the disc is accessed with a DVD-ROM, at least two directories are present: AUDIO_TS (audio title set) and VIDEO_TS (video title set). 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. IFO files are not encrypted.