The Sega CD is an add-on device for the Genesis video game console, designed and produced by Sega and released in Europe, Australia, New Zealand, Japan, and North America. In North America, it was named Sega CD, and in other regions it was named the Mega-CD. The Mega-CD name was due fact that the Genesis was named the Sega Mega-Drive elsewhere. The device adds a CD-ROM drive to the Genesis, allowing the user to play CD-based games and providing additional hardware functionality. In addition, the add-on can also play audio CDs and CD+G discs.
The development of the Sega CD was confidential; game developers were not made aware of what exactly they were working on until the add-on was finally revealed at the Tokyo Toy Show in Japan. The Mega-CD was designed to compete with the PC Engine (TurboGrafx-16) in Japan, which had a separate CD-ROM drive.
The Sega CD had been announced at the Chicago CES on January 1992. The advertising boasted full-motion video clips and CD audio soundtracks. Games delivered these, though because of the limited color palette of the Genesis video display hardware and limited data bandwidth of the system, especially considering that the CD-ROM drive was only a 1X speed unit, motion video was heavily dithered and usually limited to a rectangle in the center of the screen about 1/4 of the full screen size.