Audograph was a dictation disc format introduced in 1946 by the Gray Manufacturing Company in the US. It recorded sound by pressing grooves into soft vinyl discs, like the competing, but incompatible, SoundScriber and Voicewriter formats.
Audograph discs were thin plastic discs, recorded from the inside to the outside, the opposite of conventional phongraph discs. Another difference to phongraph discs was that the Audograph was driven by a surface-mounted wheel, meaning that its recording and playback speed decreased toward the edge of the disc (like the Compact Disc and other digital formats), to keep a more constant linear velocity and to improve playing time.
Along with a Dictabelt recorder, an Audograph machine captured sounds recorded at the time of the John F. Kennedy assassination that were reviewed by the United States House Select Committee on Assassinations.
LaserDisc was the first optical videodisc format. MCA and Philips demonstrated a laser videodisc in 1972, and it was initially marketed in 1978 in the US as MCA DiscoVision, with the first release being ‘Jaws’.
From 1980, it became known as LaserDisc, although the official name of the format was LaserVision until the early 1990s. It was released in Japan in 1981, and finally reached Europe in 1983. The technologies and concepts behind LaserDisc are the foundation for later optical disc formats, including Compact Disc, DVD, and Blu-ray.
The most common size of LaserDisc was 30 cm, allowing for up to 60 minutes per side. This is made up of two single-sided aluminum discs layered in plastic. The spiral track of a 30cm LaserDisc is 42 miles long. After one side was finished playing, a disc has to be flipped over in order to continue watching a movie, and some titles fill two or more discs. A number of 20cm LaserDiscs were also produced, and these ‘EP’ sized discs were often used for music video compilations.
There were also 12 cm CD-Video discs, and Video Single Discs. A CD-Video carried up to five minutes of LaserDisc video content (usually a music video), and up to 20 minutes of digital audio CD tracks. Video Single Discs carried only video, and were only popular in Japan.
LaserDisc was also adapted for data storage, such as for the BBC Domesday Project (as an LV-ROM) and for computer games on the Pioneer LaserActive (as an LD-ROM).
Many early LaserDiscs used a substandard adhesive to sandwich together the two sides of the disc, and this can attack the reflective aluminium layer, causing it to oxidize and lose its reflective characteristics. This was known as ‘laser rot’.
Although it was capable of higher-quality video and audio than other video formats such as VHS and Betamax, it never gained widespread use in the US, largely owing to high costs for the players and the discs. It also remained largely obscure in Europe, but was more popular in Japan and some countries of South East Asia. A total of 16.8 million LaserDisc players were sold worldwide.
The last LaserDisc titles were released in the US in 2000, and in Japan in 2001. Pioneer continued to produce players until 2009.
LD-ROM (for LaserDisc Read-Only Memory) was a variation of LV-ROM introduced by Pioneer in 1993 for use in its LaserActive home entertainment system.
LD-ROM had a capacity of 540 MB, higher than that of the LV-ROM and made possible by the use of constant linear velocity (CLV). Like LV-ROM, 12-inch discs were used, but some 8-inch discs were also available.
LD+G disks were also made available for use in the LaserActive, and like the CD+G format were used for karaoke. Add-ons for the LaserActive allowed other games for other systems on LD-ROM discs to be used, including the Mega LD (for Sega Mega CD software) and the LD-ROM² (for PC-Engine CD-ROM² software).
The LaserActive was an expensive system and a commercial failure. The last LD-ROM title was released in 1996.