Green Book (CD standard)

Green Book (CD standard)
source
Name	Green Book
Caption	The Philips-Sony Green Book defined the CD-i format.
Extension	.cdi
Owner	Philips, Sony
Released	0 1986
Genre	Optical disc data format
Container for	Digital video, Digital audio, data
Extended from	Red Book (CD-DA)

Green Book (CD standard). The Green Book is a technical specification created by Philips and Sony that defines the CD-i (Compact Disc Interactive) format. Released in 1986, it was a significant extension of the Red Book audio CD standard, designed to integrate digital audio, video, text, and graphics for interactive multimedia applications. The standard aimed to create a consumer electronics platform, leading to dedicated CD-i players and a library of software titles, though it ultimately faced limited commercial success against competing platforms like the Sega Genesis and Super Nintendo Entertainment System.

Overview

The Green Book standard was developed as a comprehensive format for interactive multimedia, merging the capabilities of a home computer with the convenience of a consumer electronics appliance. It specified a complete hardware and software system, including the Motorola 68000 microprocessor as the central processing unit and the CD-RTOS operating system, a real-time variant of OS-9. Unlike the Yellow Book standard used for CD-ROM data, the Green Book integrated audio and visual data with executable application code, allowing for seamless interactivity. The format was championed by Philips and supported by other manufacturers like Magnavox and GoldStar, who produced compatible hardware. Key applications included educational software, point-of-sale kiosks, and games, with notable titles such as Hotel Mario and Link: The Faces of Evil.

Technical specifications

The physical disc adhered to the standard Compact disc specifications, with a data capacity of up to 744 MB. The Green Book defined several encoding modes for audio and video. For audio, it supported both CD-DA (Red Book) quality and lower-bandwidth ADPCM levels, allowing for compressed speech and sound effects. Video was encoded using DVI-based compression techniques, resulting in formats like CD-i Ready and CD-i Bridge, which enabled limited playback on some standard CD players. The hardware specification mandated a minimum of 1 MB of RAM, and graphics were displayed through specific encoder chips capable of outputting to a standard television via RCA connectors. The file system and disc structure were distinct from ISO 9660, requiring specialized authoring tools from companies like OptImage.

Development and history

The development of the Green Book began in the early 1980s as a collaborative project between Philips and Sony, following their successful partnership on the Red Book audio CD. The initiative was led by key engineers within Philips' Interactive Media division, aiming to create a successor to the Laserdisc that was fully digital and interactive. A significant milestone was the public demonstration at the 1986 IFA trade show in Berlin. The first commercial CD-i player, the Philips CDI 910, launched in 1991 in markets like the United States and Japan. The format's development was influenced by the earlier CD-ROM/XA (Extended Architecture) standard, which it closely resembled. Despite initial partnerships with major studios like Disney and publishers such as McGraw-Hill, the high cost of hardware and the rise of the PC-based CD-ROM drive limited its widespread adoption.

Adoption and market impact

Market adoption of the Green Book's CD-i format was primarily concentrated in professional and niche markets rather than mainstream consumer homes. It found some success in the Netherlands and Belgium, home territories of Philips, and was used for industrial training, museum exhibits, and in-flight entertainment systems for airlines like KLM. In the consumer space, it was marketed heavily during the early 1990s but failed to compete effectively with video game consoles from Nintendo and Sega, as well as the burgeoning Windows-based multimedia PC. The release of poorly received games based on Nintendo franchises damaged its reputation among core gamers. By the mid-1990s, with the arrival of the Sony PlayStation and more powerful PCs, the CD-i platform was largely abandoned, though its technology influenced later formats like the Photo CD and aspects of the DVD specification.

Related standards

The Green Book is part of a family of Rainbow Books standards for optical media established by Philips and Sony. Its direct predecessor is the Red Book for audio CDs. It shares a close technical relationship with the Yellow Book (CD-ROM) and the subsequent CD-ROM/XA standard, which also combined compressed audio with data. The White Book standard for Video CD was derived in part from Green Book video encoding methods. Other related standards include the Orange Book for recordable CDs, the Blue Book for Enhanced CDs, and the Scarlet Book for Super Audio CD. The CD-i Bridge specification was particularly important, as it defined a subset of the Green Book that was compatible with the ISO 9660 file system, allowing discs to be read by both CD-i players and standard CD-ROM drives.

Category:CD standards Category:Computer storage media Category:Philips Category:Sony Category:1986 in technology