"CD-i, or Compact Disc Interactive, is the name of an interactive multimedia CD player developed and marketed by Royal Philips Electronics N.V. CD-i also refers to the multimedia Compact Disc standard used by the CD-i console, also known as Green Book, which was developed by Philips and Sony. Work on the CD-i began in 1984 and it was first publicly announced in 1986. The first Philips CD-i player, released in 1991 and initially priced around USD $700, is capable of playing interactive CD-i discs, Audio CDs, CD+G (CD+Graphics), Karaoke CDs, and Video CDs (VCDs), though the last requires an optional "Digital Video Card" to provide MPEG-1 decoding.

Although several video game titles were released for the system that established a cult following, the CD-i proved to be a commercial failure in that market segment and its games have been known to be some of the worst games ever made. Phillips ceased publishing video games for the platform in 1998."

Source: Wikipedia, "CD-i", available under the CC-BY-SA License.