and Philips after MCA purchased Gregg's patents, as well as the company he founded, Gauss Electrophysics. The LaserDisc was the immediate precursor to the CD, with the primary difference being that the LaserDisc encoded information through an analog process whereas the CD used digital encoding.

Key work to digitize the optical disc was performed by Toshi Doi and Kees Schouhamer Immink during 1979-1980, who worked on