Videodisk

Definition

A Videodisk (or videodisc) is a digital recording (e.g. video or audio) on an optical disk that can be played on a computer or a television set.

This technology has been replaced by DVDs, but there are still working installations in use for training.

Formats, standards and features

According to the Wikipedia there were several formats, but the Pioneer Laser Disc was by far the most popular.

• MCA DiscoVision (early name for laserdisc format) (1978)
• Pioneer LaserDisc (1980)
• RCA SelectaVision (1981)

McLean (1985) describes the technical features of the Laser Videodisc as follows:

A standard size videodisc can hold up to 30 minutes of high quality, motion video, or up to 54,000 still frames on each side. Modulation of the laser beam allows rapid, random access to any single frame on a disc side, without wear on the disc surface.

Additional features include dual audio tracks or stereo sound, variable-speed motion and single frame advance in forward or reverse modes, and the capacity for branching to specific frames or segments in response to viewer input.

Videodiscs produced better pictures and colors than VCR tapes and contents could be accessed very rapidly. These features made them attractive to instructional designers.

In an educational context, videodisks were often integrated with a microcomputer. So the typical system configuration was:

• The Videodisc player,
• A video monitor,
• A microcomputer,
• A separate computer screen,
• An interface to connect the computer and the video player.

McLean (1985) describes three levels of videodisk systems:

• A Level 1 videodisc system is a stand-alone videodisc player, which may allow dual audio and random access of still frames, freeze-frames, auto-stop, and chapter search, but has no memory or processing power.
• Level 2 systems use a stand-alone, educational/industrial player allowing disc control through an internal programmable microprocessor.
• Level 3 disc systems add the power of an external computer to a videodisc player by connecting them with an interface device, usually a computer card.

See also Grabowski's (1989) definition of these three levels which is slightly different.

Videodisks in education

Videodisks were relatively popular devices in education before CD-ROMS and DVDs became popular.

McLean (1985) described its advantages as follows:

Videodiscs could have a revolutionary impact on the use of audiovisual media in education. What makes the videodisc so attractive? Videodisc systems can combine the best features of instructional television and computer assisted instruction. They can provide individualized, self-paced instruction with feedback and remediation, while incorporating all traditional audiovisual media into one easy-to-use, durable format.

The real revolution, however, is that videodisc allows the creation of interactive video programming. Traditional video programs play linearly, in a pre-planned beginning-to-end sequence. With the videodisc, learners, instructors, and lesson designers have an opportunity for input and control over the sequence of the program. The sequence is dynamic, changing in response to overall objectives, as well as the style and level of instruction.

McLearn also describes a list of educational applications that includes:

• computer assisted instruction (CAI) formats as tutorials and drill and practice [not clear to what extent the videodisk is used here]
• Simulating expensive or dangerous procedures
• Simulating human interactions to provide realistic practice in interpersonal situations, such as between sales persons and clients, teachers and students, medical personnel and patients, counselors and their clients, and teachers and parents.
• Teaching standardized procedures that must be performed in a specific way, such as first aid training
• Storing audiovisual databases, such as collections of still photographs or illustrations

Examples

• Anchored instruction
• Career counseling programs: see "Knowledge for Youth About Careers (KYAC) is one such interactive, multimedia career program" described by Bradshaw. This was based on attribution change theory and self-efficacy theory.

Links

http://en.wikipedia.org/wiki/Videodisc

References

• DeBloois, Michael L., ed. VideoDisc/Microcomputer Courseware Design. Englewood Cliffs, N.J.: Educational Technology Publications, 1982. ISBN 0877781834.

• McLean, Lois (1985). Videodiscs in Education. ERIC Digest, ED270103 HTML

• Bradshaw, Richard A. Delivery of Career Counseling Services: Videodisc & Multimedia Career Interventions, ERIC Digest ED414516, HTML

• Grabowski, Barbara L. (1989). Interactive Videodisc: An Emerging Technology for Educators. ERIC Digest ED315064. HTML

• Schneider, Edward W., and Junius L. Brennion. (1980). The Instructional Media Library: VideoDiscs, (Volume 16). Englewood Cliffs, NJ: Educational Technology Publications. ISBN 0877781761. 1981.