In 1991, several manufacturers announced specifications for what would become known as "MUSE" Laserdisc. Encoded using technology adopted from "Hi-Vision" (Japanese HDTV) hardware, MUSE discs would operate like standard Laserdiscs but would contain material transferred in High Definition (1080i) widescreen. The MUSE players were also capable of playing standard NTSC format discs and are said to have superior performance to non-MUSE players. The MUSE-capable players had several noteworthy advantages over standard Laserdisc players, including a red laser with a much narrower wavelength than the lasers found in standard players. The red laser was capable of reading through disc defects such as scratches and even mild disc-rot that would cause most other players to stop, stutter or drop-out. Crosstalk was not an issue with MUSE discs, and the narrow wavelength of the laser allowed for the virtual elimination of crosstalk with normal discs. In order to view MUSE encoded discs, it was necessary to have a MUSE decoder in addition to a compatible player and an HDTV. Equipment prices were high, especially for early HDTVs which generally eclipsed $10,000 USD, and even in Japan the market for MUSE was tiny. Players and discs were never officially sold in North America, although several distributors imported MUSE discs along with other import titles. Terminator 2: Judgment Day, Lawrence of Arabia, A League of Their Own, Bugsy, Close Encounters of the Third Kind, Bram Stoker's Dracula and Chaplin were among the theatrical releases available on MUSE. Several documentaries, including one about Formula One at Japan's Suzuka Circuit were also released.
Towards the end of the format's life, a small number of discs were sold in Japan which contained an anamorphic image technology marketed as "squeeze", effectively the same as the 16:9 anamorphic output from a DVD player. Among the very few films available in this format were Terminator 2: Judgment Day, Basic Instinct, and Cliffhanger. Unlike MUSE discs, Squeeze titles required a widescreen television set to display the squeezed image correctly, and they ran at standard resolution, offering 400 horizontal lines (they were mainly NTSC, only two PAL "Squeeze" titles were produced). Widescreen sets cost considerably more than a standard set at the time, which played a major part in why the format never caught on.
"LD singles" which are 18 cm (approx. 8", the same size as a 45-RPM record) across rather than the full 30 cm (approx. 12") size, were also published. LD singles only contained a few minutes of video, enough for a music video or two. They are much rarer than the full-size LDs, especially in North America.
Other forms of "single"-style discs that were playable on laserdisc players were CD Video (CD-V) discs, and Video Single Discs (VSD). A CD-V carried up to 5 minutes of analog laserdisc-type video content (usually a music video), as well as up to 20 minutes of digital audio CD tracks. CD-Vs are not to be confused with Video CDs, which are all digital, and can only be played on computers, CD-i players, DVD players, VCD players, and later-model laserdisc players (such as the DVL series from Pioneer) that can also play DVDs. VSDs were the same as CD-Vs, but without the audio CD tracks. CD-Vs were somewhat popular for a brief time worldwide, but soon faded from view. VSDs were popular only in Japan and other parts of Asia, and were never really introduced to the rest of the world. Both CD-V and VSD used a 5-inch disc, much like audio CD.
Some laser discs, called "picture discs", have artistic etching on one side of the disc to make the disc more visually attractive than the standard shiny silver surface. This etching might look like a movie character, logo, or other promotional material. Sometimes that side of the LD would be made with colored plastic rather than the clear material used for the data side. Picture disc LDs only had video material on one side as the "picture" side could not contain any data. Picture discs are rare in North America.
Pioneer Electronics, one of the format's largest supporters/investors, was also deeply involved in the karaoke business in Japan, and used laserdiscs as the storage medium for music and additional content such as graphics. The format was generally called LD+G. While several other karaoke labels manufactured laserdiscs, there was nothing like the breadth of competition in that industry that exists now, as almost all manufacturers have transitioned to CD+G discs (en route, possibly, to a new DVD based format).
Pioneer also marketed a format similar to LD+G, called LD-ROM. It was used by Pioneer's LaserActive interactive laserdisc player/video game console introduced in 1993, and contained analog video in combination with digital data. LD-ROM was used for several games that could be played on the LaserActive player/console.
A CRV Disc with a VHS tape for size comparisonAnother type of video media, CRVdisc, or "Component Recordable Video Disc" were available for a short time, mostly to professionals. Developed by Sony, CRVdiscs resemble early PC CD-ROM caddies with a disc inside resembling a full sized LD. CRVdiscs were blank media that could be recorded once on each side (much like WORM media, such as CD-R discs). CRVdisc was rarely used by the consumer due to the high cost of the equipment and media, and were used largely for backup storage in professional/commercial applications.
Another form of recordable laserdisc that is completely playback-compatible with the Laserdisc format (unlike CRVdisc, due to its caddy enclosure) is the RLV, or Recordable LaserVision disc. It was developed and first marketed by the Optical Disc Corporation (ODC, now ODC Nimbus) in 1984. RLV discs, like CRVdisc, are also a WORM technology, and function exactly like a CD-R disc. RLV discs look almost exactly like standard laserdiscs, and can play in any standard laserdisc player after they've been recorded. The only difference an RLV disc has over regular factory-pressed laserdiscs is their reflective purple-violet color resulting from the dye embedded in the reflective layer of the disc to make it recordable, as opposed to the silver mirror appearance of regular LDs. The color of RLVs look almost exactly like the purplish color of the dye used for some DVD-R and DVD+R discs. RLVs were popular for making short-run quantities of laserdiscs for specialized applications such as interactive kiosks and flight simulators.