The laser disc (LD) is a home video disc format, and was the first commercial optical disc storage medium. Initially marketed as Discovision in 1978, the technology was licensed and sold as Reflective Optical Videodisc, Laser Videodisc, Laser vision, Disco-Vision, Disco Vision, and MCA Disco Vision until Pioneer Electronics purchased the majority stake in the format and marketed it as laser disc in the mid to late 1980s.
The technology and concepts provided with the Laserdisc would become the forerunner to Compact Discs and DVDs.
Regarding the advantages part, laserdisc players were known to provide the operator with a great degree of control over the playback process.
Unlike many DVD players, the operator is immediately tied to the transport mechanism: pause, fast-forward, and fast-reverse commands are always accepted. There were no "User Prohibited Options" where content protection code instructs the player to refuse commands to skip a specific part (such as fast forwarding through copyright warnings).
However, some DVD players, particularly in the higher-end units, have the ability to ignore the blocking code and play the video without restrictions. With CAV Laserdiscs the user can jump directly to any individual frame of a video simply by entering the frame number on the remote keypad, a feature not common among DVD players. However, some DVD players have cache features which stores a certain amount of the video in RAM which allows the player to index a DVD as quickly as an LD, even down to the frame in some players.
Another advantage of Laserdisc is that damaged spots can be skipped, while a DVD will become unplayable. Some newer DVD players feature a repair+skip algorithm, which alleviates this problem by continuing to play the disc, filling in unreadable areas of the picture with blank space or a frozen frame of the last readable image and sound. The success of this feature depends upon the amount of damage.
Laser disc players, when working in full analog, recover from such errors faster than DVD players. Direct comparison is, however, almost impossible due to the sheer size differences between the two media. A 1" scratch on a DVD will probably cause more problems than a 1" scratch on an Laserdisc, but a fingerprint taking up 1% of the area of a DVD would almost certainly cause fewer problems than a similar mark covering 1% of the surface of a Laserdisc.
Some laser disc proponents believe analog laser disc is capable of higher quality than the lossy nature of DVD. Early DVD demo discs often had compression or encoding problems, lending additional support to such claims at the time. Proponents of Laserdisc argue that Laserdisc maintains a "smoother", more "film-like", natural image while DVD still looks slightly more artificial. This is similar to the CD versus LP sound quality debates common in the audiophile community.
Despite the apparent advantages over competing technology at the time (namely VHS), the format was not without its flaws. The discs were 12" in diameter, heavy, cumbersome, more prone to damage when handling than a VHS tape, and manufacturers did not market LD units with recording capabilities to consumers. Also, because of their size, greater mechanical effort was required to spin the discs at the proper speed, resulting in much more noise generated than other media.
In addition, perfect still frames and random access to individual still frames were limited only to the more expensive CAV discs, which only had a playing time of approximately 30 minutes per side. In later years, Pioneer and other manufacturers overcame this limitation by incorporating a digital memory buffer, which "grabbed" a single frame from a CLV title.
Despite their large physical size, the space-consuming analog video signal of a Laserdisc limited playback duration to 30 (CAV) or 60 minutes (CLV) per side because of the hardware manufacturer's refusal to reduce line count for increased playtime.
After one side was finished playing, a disc would have to be flipped over in order to continue watching the film, and some films required two or more discs. Many players, especially units built after the mid-1980s, could "flip" discs automatically by rotating the optical pickup to the other side of the disc, but this was accompanied by a pause in the movie during the side change.
If the movie was longer than what could be stored on 2 sides of a single disc, manually swapping to a second disc would be necessary at some point during the film. One exception to this rule is the Pioneer LD-W1, which had two disc platters.
