LaserDisc
An earlier optical disc used for full-motion video and interactive training. It was introduced in the late 1970s and became obsolete in the 1990s. Videodisc systems based on a stylus were introduced (see CED), but only the optical-based LaserDisc survived, although never very popular. Video CDs, and ultimately DVDs, caused its demise.
Analog LaserVision
The LaserDisc was based on the LaserVision technology, a combination of the MCA Disco-Vision and Philips Video Long Play (VLP) systems. It used the CLV format, recording an analog composite video signal on a continuous, spiraling track. Each side of a 12" platter held one hour of video in 108,000 frames. For interactive training and games, the CAV format was used with each circular track holding one video frame. The 54,000 frames allowed 30 minutes of video per side.
Digital Audio Was Added
Early LaserDiscs recorded only analog sound, but subsequent discs contained analog and digital soundtracks. Newer players defaulted to the digital sound if available. Some players let the user select the soundtrack, supporting multiple languages and other annotations on the same disc. See CLV and CAV.
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| LaserDisc and DVD |
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| This 12" LaserDisc platter looks like a dinosaur compared to the DVD on top of the case, but in the 1980s, LaserDiscs were very high tech. |