CD-i FAQ

Compact Disc Interactive, or CD-i, is a standard for optical media and its associated hardware developed by both Philips and Sony. An extension of CD-DA (digital audio) and CD-ROM (read-only memory), the CD-i format is specified in the Green Book, the third of the Rainbow Books that outlined a variety of Compact Disc format specifications.

Specifically, CD-i was designed to combine audio, text, and graphics in a format that could be played on dedicated CD-i players.

CD-i is, contrary to popular belief, not a game system, nor was the format intended for the development, publishing, and playback of games. Philips intended for the format to be used 

A CD-i Player is, as the name suggests, a hardware device designed to play back CD-i format discs. CD-i players have to meet the following hardware specifications as defined in the Green Book:

• CPU

  • Philips SCC68070 (based off the Motorola 68000) @ 15.5 MHz

• RAM

  • 1 MB of RAM on "base-case" players

  • Additional 1.5 MB of RAM integrated into the optional Digital Video Cartridge

• Graphics/Video

  • Philips SCC66470 VSC (Video and Systems Controller)

  • Resolution of 256x224 up to 512x480

  • 16.7 million colors, with 32,768 colors on screen at once

  • Optional Digital Video Cartridge (DVC) for processing MPEG-1 digital video (used for CD-i Digital Video and Video CD titles)

  • Output in NTSC or PAL

• Audio

  • MCD 221 sound chip

  • ADPC 8-bit sound

  • 16-bit stereo sound up to 44.1 kHz sampling rate

• Operating System

  • CD-RTOS (Compact Disc Real-Time Operating System), based on Microware OS9

• Storage

  • Single-speed CD-ROM drive

  • Up to 744 MB of storage on a single CD-i disc

  • 8-32 KB NVRAM for storing data on the player

In short, CD-i players are complete computer systems with their own CPU, video and audio processing hardware, RAM, operating system, and input/output devices. They are more advanced than the CD players and CD-ROM drives that came before them.

CD-i players are capable of playing back the following CD formats:

• CD-i (Compact Disc Interactive)

• CD-DA (Compact Disc Digital Audio)

• CD-G (Compact Disc + Graphics)

• Photo CD

• Video CD/CD-DV (Compact Disc Digital Video) with the addition of a Digital Video Cartridge (DVC)

In laymans terms, this means that CD-i players are capable of playing more than games, as most people believe. They are capable of playing and displaying photos, movies/videos, photos, music, and karaoke CDs. Philips had intended them to serve as multimedia centers for the living room.

The CD-i platform's ability to be used for games is moreso a consequence of the fact that the format was designed for the playback of interactive multimedia with graphics, audio, and text. Video games are also interactive multimedia, with graphics, audio, and text. The overlap between the intended use of the format and video games is quite minimal, leading developers to create and publish games for the CD-i platform.

Philips initially didn't want the format to be used for video games, and it's evident in the hardware. Game consoles of the time had specialized video hardware that allowed for many sprites to be displayed and rapidly manipulated across screens that could be rapidly and smoothly scrolled in one or more directions, and did so in lower resolutions and with limited colors. CD-i players did not have that. Their hardware was designed for the playback of high resolution video and graphics with a higher number of colors on-screen at once. You will notice that in the games that weren't just interactive movies (like the Zelda titles), everything happens rather slowly on-screen, and scrolling is limited to about 1-1/2 to 2 whole screens either vertically or horizontally, but not both.

With that said, sales of the CD-i platform struggled towards the latter half of its life, leading Philips to pivot towards marketing it as a game platform as a last-ditch effort to recover the money they spent on the platform. This led to less expensive models like the 450 being manufactured, which resembled other CD-based game consoles of the time. After the platform's demise in 1999, it was remembered mainly for the Nintendo licensed titles, earning it a reputation as a subpar game console, rather than a multimedia format and hardware platform.

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