Philips CD-i 1984 and it was first publicly announced in 1986. The first Philips CD-i player, released in 1991 and initially priced around US$1,000, was capable of playing interactive CD-i discs, Audio CDs, CD+G (CD+Graphics), Karaoke CDs, Photo CDs and Video CDs (VCDs), though the latter required an optional "Digital Video Card" to provide MPEG-1 decoding. Philips also licensed the CD-i format to other manufacturers for use, and there were also CD-i players by Sony under the "Intelligent Discman" brand. Philips marketed the CD-i as a "home entertainment system" in Europe, but more as a games and educational machine in the U.S.
Green Book (CD standard) on CD-i tracks, as well as certain specific files that are required to be present in a CD-i compatible disc. The CD-i Ready format is a type of bridge format, also designed by Philips, that defines discs compatible with CD Digital audio players and CD-i players. This format puts CD-i software and data into the pregap of Track 1. The CD-i Bridge format, defined in Philips' White Book, is a transitional format allowing bridge discs to be played both on CD-ROM drives and on CD-i players. Green Book (CD standard) The "Green Book", formally known as the "CD-i Full Functional