LaserDiscs

A Philips LaserDisc player.
Photo courtesy Werner Kretz

LaserDisc (LD) is a home video format and the first commercial optical disc storage medium. Initially licensed, sold, and marketed as MCA DiscoVision in 1978. Later, Pioneer Electronics purchased the majority stake in the format and marketed it as both LaserVision (format name) and LaserDisc (brand name) in 1980.

Laser discs had superior video and sound to VHS tapes. They used digital audio as opposed to the analog audio found on tapes. Laser disc also offered greater video resolution than tape. The different layers on the disc allowed the movie to broadcast in multiple audio formats, so you could activate features, such as commentary by actors and directors and dubbing in different languages. Laser discs also offered scene selection, a large improvement over VHS, where the only options were "forward" and "reverse" to jump to a new scene. The random-access features of LaserDisc players to create interactive movies in the same concept like a game. You can watch a interactive player in action from 1985 here.

The first laser disc was released to the public on December 15, 1978. This was almost 4 years before the first compact disc and a little less than 20 years before DVDs. The first LaserDisc movie release was "Jaws".  

Technical Details 

The standard home video Laserdisc was 11.81 in (30 cm) in diameter and made up of two single-sided aluminum discs layered in plastic. Although appearing similar to compact discs or DVDs, Laserdiscs used analog video stored in the composite domain with analog sound and/or some form of digital audio. However, despite its analog nature, the Laserdisc at its most fundamental level was still recorded as a series of pits and lands much like CDs, DVDs, and Blu-rays. The spiral track of a Laserdisc is 42 miles (67 km) long. Early Laserdiscs featured in 1978 were entirely analog but the format evolved to incorporate digital stereo sound in CD format, and later multi-channel formats such as Dolby Digital and DTS.

Types of LaserDiscs :

• CAV (Constant Angular Velocity) or Standard Play discs supported several unique features such as freeze frame, variable slow motion and reverse. CAV discs were spun at a constant rotational speed (1800 rpm for 525 line and 1500 rpm for 625 line discs) during playback, with one video frame read per revolution. In this mode, 54,000 individual frames (30 minutes of audio/video) could be stored on a single side of a CAV disc.
• CLV (Constant Linear Velocity) or Extended Play discs offer simple playback on all but the high-end Laserdisc players incorporating a digital frame store. These high-end Laserdisc players could add features not normally available to CLV discs such as variable forward and reverse, and a VCR-like "pause". By gradually slowing down their rotational speed (1,800–600 rpm) CLV encoded discs could store 60 minutes of audio/video per side, or two hours per disc. The vast majority of titles were only available in CLV.
• CAA (Constant Angular Acceleration). In the early 1980s, due to problems with crosstalk distortion on CLV extended play Laserdiscs, Pioneer Video introduced CAA formatting for extended play discs. Constant Angular Acceleration is very similar to Constant Linear Velocity, save for the fact that CAA varies the angular rotation of the disc in controlled steps instead of gradually slowing down in a steady linear pace as a CLV disc is read. With the exception of 3M/Imation, all Laserdisc manufacturers adopted the CAA encoding scheme. CAA encoding noticeably improved picture quality and greatly reduced crosstalk and other tracking problems.

Audio :

Audio could be stored in either analog or digital format and in a variety of surround sound formats; NTSC discs could carry two analog audio tracks, plus two uncompressed PCM digital audio tracks, which were CD encoded channels, (EFM, CIRC, 16-bit and 44.1 kHz sample rate). PAL discs could carry one pair of audio tracks, either analog or digital. Dolby Digital (also called AC-3) and DTS first became available on Laserdisc, and Star Wars: Episode I which was released on Laserdisc in Japan, is among the first home video releases ever to include 6.1 channel Dolby Digital EX Surround.

Laserdiscs store Dolby Digital in a frequency modulated form within a track normally used for analog audio. Extracting Dolby Digital from a Laserdisc required a player equipped with a special "AC-3 RF" output and an external demodulator in addition to an AC-3 decoder. The demodulator was necessary to convert the 2.88 MHz modulated AC-3 information on the disc into a 384 kbit/s signal that the decoder could handle. DTS audio, when available on a disc, replaced the digital audio tracks; hearing DTS sound required only an S/PDIF compliant digital connection to a DTS decoder.

Reasons of Failure

LaserDisc Compared with a VHS tape!

Although the format was capable of offering higher-quality video and audio than the VHS and Betamax videocassette systems, Laserdisc never managed to gain widespread use in North America, largely owing to high costs for the players and the video titles themselves.  It also remained a largely obscure format in Europe and Australia. However, it was much more popular in Japan and in the more affluent regions of southeast Asia, such as Hong Kong, Malaysia and Singapore. Laserdisc was the prevalent rental video medium in Hong Kong during the 1990s. Significantly, the technologies and concepts behind Laserdisc are the foundation for later and more popular optical disc formats, including Compact Discs and DVDs.

Overall the main reasons of failure are:

• Expensive hardware
• Very expensive recording hardware
• VCR were much cheaper
• Expensive movies
• No interest in Europe/Australia
• Size of the Disk

Summary

You can watch a summary of futures and disadvantages of  LaserDisc Players here.  Laser discs was popular among collectors because they featured exclusive material that cannot be found on DVD releases. Laser disc was popular in Japan, where they were sold until 2001. The format no longer has broad commercial value, but there is a market for old discs and players among collectors. You can still find some shops selling LaserDiscks, such as ebay, LaserDisc Database, Laser Disc Shop, Discount laser Disc, DaDon's laserdiscs, and LaserDisc Vault.

References:

1. http://en.wikipedia.org/wiki/Laserdisc