LV-ROM
{{short description|LaserDisc-based format designed for the simultaneous storage of analog video and computer software}}
File:BBC Master AIV (Domesday System) (1).jpg
LV-ROM (LaserVision Read-Only Memory) and LD-ROM (LaserDisc Read-Only Memory) are similar but incompatible optical disc formats that combine analog LaserDisc video with digitally encoded computer data. Both were developed to support interactive multimedia by integrating analog video playback with computer-controlled navigation and overlays. While LV-ROM was developed in the 1980s primarily for educational and documentary purposes, LD-ROM was introduced in the 1990s to support video game software for consumer entertainment systems.
LV-ROM
{{Infobox storage medium
| title = LV-ROM
| type = Read-only optical disc
| encoding = {{Unbulleted indent list
| Pulse-width modulation (analog images)
| Advanced Disc Filing System (data)
}}
| capacity = 324 MB of data and 54,000 image frames per side
| blocksize =
| read = Laser diode
| write =
| standard =
| owner = Philips
| use = Interactive media
| dimensions = {{cvt|300|mm|2}}
| weight =
| extended from = LaserDisc
| extended to = LD-ROM
}}
The LV-ROM format was developed by Philips in the early 1980s. Like standard play LaserDiscs, LV-ROM employed constant angular velocity playback with analog video and audio encoded using pulse-width modulation, while digital data was stored using the Advanced Disc Filing System developed by Acorn Computers.
Each side of an LV-ROM disc can hold up to 324 megabytes of digital data and approximately 54,000 frames which could either be images or analog video (up to 36 minutes at 25 frames per second).{{cite tech report |url=https://cartogis.org/docs/proceedings/archive/auto-carto-8/pdf/the-bbc-domesday-project-a-nation-wide-cis-for-$4448.pdf |title=The BBC Domesday System: A Nationwide CIS FOR $4448 |last1=Rhind |first1=David |last2=Openshaw |first2=Stan |year=1986 |access-date=12 March 2025 |archive-url=https://web.archive.org/web/20160315033449/http://mapcontext.com/autocarto/proceedings/auto-carto-8/pdf/the-bbc-domesday-project-a-nation-wide-cis-for-$4448.pdf |url-status=live |archive-date=15 March 2016}}
LV-ROM was used most prominently in the BBC Domesday Project, a major British multimedia initiative between 1984 and 1986 that compiled video interviews, children's writings, statistical data, and maps. The discs were played using a BBC Master computer (built by Acorn Computers) connected to a Philips AIV VP415 LaserDisc player via SCSI.The BBC Master, introduced by Acorn Computers in 1986, was one of the first home computers to feature the new SCSI-1 parallel bus. A genlock allowed the system to overlay computer graphics on the analog video. Navigation was handled via a trackball interface.
LD-ROM
{{Infobox storage medium
| title = LD-ROM
| logo =
| image =
| caption =
| type = Read-only optical disc
| encoding = Constant linear velocity
| capacity = 540 MB per side (300 mm disc)
| blocksize =
| read = Laser diode
| write =
| standard =
| owner = Pioneer
| use = Video games
| dimensions = {{cvt|300|mm|2}} or {{cvt|200|mm|2}}
| weight =
| extended from = LV-ROM
| extended to =
}}
The LD-ROM format was developed by Pioneer and introduced in 1993 for use with the LaserActive, a hybrid LaserDisc player, video game console, and CD player. Unlike LV-ROM, which used constant angular velocity for frame-accurate video playback, LD-ROM employed constant linear velocity, like had been done with LaserDisc extended play, to maximize storage capacity reaching up to 540 MB of digital data per side on typical {{Convert|300|mm|sp=us|adj=on}} disc. A smaller {{Convert|200|mm|abbr=on|sp=us|adj=on}} disc was also available, offering a reduced capacity. The format used a different file system from LV-ROM, and analog video/audio quality was affected by the CLV encoding approach.
The LaserActive system supported video games on the LD-ROM disc, if the system was equipped with the optional expansion modules (PACs) that enabled compatibility with Sega Genesis and TurboGrafx-16 game media.
Variants of LD-ROM include:
- MEGA LD – Used for software compatible with the Mega-CD/Sega CD platform.
- LD-ROM² – Used for software compatible with the PC Engine CD-ROM² platform.
- LD-G – Discs designed for karaoke content, similar to CD+G.
References
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