Green Book (CD standard)

The "Green Book", formally known as the "CD-i Full Functional Specification", is a CD standard developed in 1986 by Philips and Sony that defines the format for interactive, multimedia compact discs designed for CD-i players. The standard was originally not freely available and had to be licensed from Philips. However, the 1994 version of the standard was eventually made available for free by Philips.