Dolby AC-3

Used in discs (DVD and Blu-ray) as well as game consoles and HDTV broadcasts, Dolby Digital AC-3 is a lossy audio compression technology. Developed by Dolby Laboratories as Dolby Stereo Digital it was first used for digital sound in 35mm cinema. Renamed in 1994, Dolby has also added a lossless audio compression called TrueHD.