Spring 1985 // Volume 23 // Number 1 // Feature Articles // 1FEA5

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The Videodisc: More Than a Toy

Extension can no longer ignore this technology.

Robert J. Florell
Extension Staff Development Specialist
Professor, Adult and Continuing Education
University of Nebraska - Lincoln

Ronald W. Nugent
Group Director, Videodisc Design and Production
University of Nebraska - Lincoln

During its 70 years of existence, the Cooperative Extension Service has always searched for new and improved methods of delivering educational information. This search continues today as new educational delivery systems are developed. Many of these newer methods use television, including closedcircuit TV, cable systems to localized areas, one-way informational service (Teletext), and interactive television (Videotext).

Another innovation in television delivery system technology emerged about five years ago. This innovation is the videodisc and videodisc playback unit. In contrast to the videotape, the information is recorded on a disc.

What is the videodisc? How does it compare to videotape in terms of its potential use as a tool to deliver educational materials via the television screen? Why hasn't its rate of adoption been faster? To answer these questions, its necessary to describe videodisc technology, list its pros and cons, and discuss how Extension might use this technology in its programming.

Videodisc Technology

According to Nugent, the videodisc is a very dense audio-visual storage medium using a flat round record that can't be erased or re-recorded.1 An optical system in the videodisc player uses a laser beam that strikes microscopic pits on the disc's surface and interrupts the beam. The interrupted beam is then translated into both video and audio information that's played back on a television receiver or monitor.2

Optical videodiscs look like a silver, long-playing record. Information can be impressed on both sides with up to one hour of continuous time per side. Each disc has a clear plastic coating that protects the disc from damage.

Three-Step Process

Videodiscs are recorded in a three-step process. First, a videotape with all audio-visual elements is produced. This premaster videotape is then used as the input source to create a master videodisc. From this master, the replicas, which are the actual release discs, are made by a molding or stamping process.

Videodisc mastering costs about $2,000. The replicas cost from $6 to $18 each, depending on quantity and whether the disc has material on both sides.

Videodisc Players

Optical videodisc players range in price from $600 to $1,800 depending on the capabilities of the players. Optical players are made by Sony, Hitachi, Pioneer Electronics, and Philips. The now terminated RCA capacitance player was selling for as little as $200.3

Reasons for Interest

The interest in videodisc technology is based on two factors.

The first factor is the potential of the videodisc as a low cost distribution medium for audio-visual material. Thousands of copies can be made from a single master.

The second factor is the nature of the medium. Because of the extreme density of information storage across the surface of a videodisc, any point can be accessed within a few seconds (compared to minutes on a videotape). Presentation of material can be designed in many different combinations: continuous play of the disc, continuous play of short segments, slow-motion play, or freezing single frames (of which there are 54,000).

The system's full potential is realized when the videodisc unit is interfaced with a microcomputer. The user has access to computer memory and graphics in addition to the unique features of the videodisc player. Programmed instruction can now include full color motion, sound from two separate audio tracts, and hundreds or even thousands of stills. Through computer control, all of these elements can be orchestrated to provide very complex interactive instruction sequences, high level storage, and retrieval of thousands of images.

A distinct advantage of videodisc instruction is that it's self-paced. Thus, instruction for any task from making a pantsuit to pruning a tree can be done very efficiently.

Pros and Cons of Videodiscs

Favorable Reactions

In 1980, the videodisc design/production group, KUON-TV, University of Nebraska-Lincoln, conducted a workshop on videodisc technology for a group of audio-visual media directors, computer-assisted instruction (CAI) providers, and college professors of business administration. Their reactions to video disc technology as a potential tool for education and training werle:4

  1. The equipment and videodiscs were easy to use.
  2. Picture and sound quality were excellent.
  3. The durability of the videodisc and the lack of wear and tear on the software were impressive.
  4. The speed of the random access was a desirable feature.
  5. Cost of videodisc software was less than videotape for large orders.

Barriers to Adoption

The three groups5 also identified what they considered the disadvantages of videodisc technology:

  1. High cost of the player.
  2. Difficulty of moving equipment.
  3. Faculty members' lack of technological know-how.
  4. Use of multiple choice in branching strategies.
  5. Possible incompatibility of models of interfaces.
  6. High cost of producing and pre-programming discs.

Implications for Extension

As leaders in the dissemination of information, Extension professionals need to study possible uses of videodisc technology for Extension programming.

These uses might include: (1) a storage medium for audio-visual presentations, (2) a source of educational information through interactive television, and (3) a tool for individualized instruction.

Storage Medium

Most state Cooperative Extension Services maintain a library of videotapes, films, slides, and audiotapes on university campuses. This information could be recorded on a videodisc and reproduced for storage and use in county and district or area Extension offices. This would provide an instant source of a wide variety of audio-visual material for Extension programming.

Information Via Interactive Television

Recent image and needs surveys6 of potential Extension audiences in Nebraska reveal that individualized learning from newspapers, newsletters, or television is more preferred than group seminars and meetings. Thus, it appears that with crowded schedules, people are more inclined towards learning activities at home. Videodisc technology combined with interactive television could bring specific Extension programming directly Into the home. For example, at the touch of a button, a program on Crabgrass Control or Calibrating a Sprayer would appear instantly on the home television screen.

Tool for Individual Instruction

"Self-Learning Centers" located in Extension offices can provide a quick, easy way for a person to learn about a specific topic. Educational information stored on a videodisc would be instantly available on the television monitor. It might be presented as programmed instruction. For example:

A learner watches an instructional sequence. Following the sequence, the disc automatically freezes on a frame that displays a true-false question. Depending on the learner's response, the disc will "branch"to a continuation sequence or to a remediation sequence, followed by further questioning, etc.7


Clearly, videodisc technology is no longer a laboratory curiosity. Since its development five years ago, it hasn't been as readily accepted as other new technologies. However, it has too many unique advantages to be ignored. The advantages of the videodisc over technologies such as the videotape are: (1) speedy access time to any of the stored information, (2) large storage capacity of information, (3) superior single frame viewing without damage to the medium, (4) small amount of storage space needed for the videodisc, (5) durability of the videodisc, (6) no moving parts to wear out on the videodisc, (7) cheaper to mail than a videotape, and (8) cheaper to reproduce than a videotape when 300 or more copies are needed.

Clearly, the videodisc player may be a future necessity in every Extension office, but at the moment, "its time has not come."


  1. John Melssner, "Nebraskan Pioneers in Videodiscs," Daily Nebraskan, January 27, 1984.
  2. Ron Nugent, An Overview of Videodisc Technology, Project Paper No. 4 (Lincoln: University of Nebraska, Videodisc Design/Production Group, KUON-TV, October, 1980).
  3. Until recently, two types of videodisc systems existed: optical and capacitance. The capacitance system developed by RCA has recently been discontinued. Although players and discs will be sold for some time for the home entertainment market, virtually all of the current educational/industrial applications use optical systems.
  4. A Summary of Research on Potential Educational Markets for Videodisc Programming, Project Paper No. 1 (Lincoln: University of Nebraska, Videodisc Design/Production Group, KUON-TV, November, 1979).
  5. Ibid.
  6. Marilee Karlberg, S. Kay Rockwell, and Robert J. Florell, An Extension Image and Needs Assessment Survey in Five Nebraska Counties (Lincoln: University of Nebraska, Cooperative Extension Service, March, 1980).
  7. Nugent, An Overview of Videodisc Technology.