LV-ROM

Last updated
LV-ROM
Media type Read-only optical disc
Encoding Pulse-width modulation (analog)
Capacity324 megabytes of digital information, or 54,000 frames of PWM-encoded analog video (per side)
Read mechanism Laser diode
Developed by Philips
Dimensions30 cm (11.81 in)
Usage Interactive media
Extended from Laserdisc
Extended to LD-ROM
Philips VP415 Laserdisc player Philips VP415 (1).jpg
Philips VP415 Laserdisc player

LV-ROM is an optical disc format developed by Philips Electronics to integrate analog video and computer software for interactive multimedia. The LV-ROM is a specialized variation of the CAV Laserdisc. LV-ROM is an initialism for "LaserVision Read-Only Memory".

Contents

Like Laserdisc, LV-ROM discs store analog audio and video by encoding it in pulse-width modulation. However, LV-ROM also stores computer files via the Advanced Disc Filing System, which is the file system used by Acorn Computers. An LV-ROM disc can store up to 324 megabytes of digital information, or up to 54,000 frames of analog video [1] (36 minutes with a frame rate of 25 fps) per side.

The format had only one application: to publish documentary video, children's writings, and other historical records compiled from 1984 to 1986 for the BBC Domesday Project.[ disputed discuss ] The Domesday Project LV-ROM discs were played using a BBC Master computer connected via SCSI-1 [2] to a Philips AIV VP415 Laserdisc player. [1] A genlock enabled the software stored on the LV-ROM to display computer graphics over the analog video on the BBC Master's computer screen. The buttons and menus of the user interface were accessed with a trackball. The Philips VP415 was shown in the 1989 James Bond film: “License to Kill”.

LD-ROM

In the early 1990s, Pioneer Corporation deployed a variation of the 30-cm LV-ROM with a different file system and a 540 megabyte capacity. This disc format, called LD-ROM, stored the software for a home entertainment system that Pioneer introduced in 1993. This system, the Pioneer LaserActive, was a cross-platform video game console, Laserdisc player, and CD player.

LD-ROMs owe their greater capacity to a design for constant linear velocity (CLV) playback. Like magnetic tape, the playback speed corresponds with picture quality and audio definition of analog audio-video streams. Since Pioneer intended LD-ROMs primarily for computer software, they chose CLV technology to increase the file storage capacity.

Specialized LD-ROM discs include the MEGA LD (for Sega Mega CD/Sega CD software), the LD-G (for karaoke data or digital photo albums; similar to CD+G), and the LD-ROM² (for PC-Engine CD-ROM² software). Such software was published either on 30-centimeter discs or on 20-centimeter discs with a lesser storage capacity.

Whereas LV-ROM is an abbreviation of "LaserVision Read-Only Memory", LD-ROM is an abbreviation of "LaserDisc Read-Only Memory".

References

  1. 1 2 Rhind, David; Openshaw, Stan (1986). The BBC Domesday System: A Nationwide CIS FOR $4448 (PDF) (Technical report). Archived (PDF) from the original on 15 March 2016. Retrieved 12 March 2025.
  2. The BBC Master, introduced by Acorn Computers in 1986, was one of the first home computers to feature the new SCSI-1 parallel communications bus.

See also