CD player in 1970. Following litigation, Sony and Philips licensed Russell's patents (then held by a Canadian company, Optical Recording Corp.) in the 1980s. The Compact Disc is an evolution of LaserDisc technology, where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Prototypes were developed by Philips and Sony independently in the late 1970s. In 1979, Sony and Philips set up a joint task force of engineers to design a new digital audio disc. After a year of experimentation and discussion, the "Red Book" CD-DA standard was published in 1980. After their
CD Video that can play CD-V discs is the Pioneer CLD-1010 from 1987. Though it is a CD-based format, CD Video was never given a rainbow book designation; the idea of encoding analogue video, which is incompatible between different regions, was poorly received by CD stakeholders other than Philips, who had not consulted them prior to demonstrating the format to the music industry. CD Video discs have a distinctive gold color, to differentiate them from regular silver-colored audio CDs. This is a characteristic that would later be replicated in HVD, a more advanced disc format. A similar version of CD Video called