Like Rip Van Winkle, the videodisc lay dormant for 20 years, sleeping in the shade of the more popular videocassette. But now it has awakened to a technically changed world of home electronics.
It has become the fastest-growing segment of the video market, with an estimated seven million discs to be sold this year.
What roused the disc from its somnolence is the current popularity of large-screen television sets, which benefit visibly from the better video signal obtained from discs.
Unlike most VCRs, videodiscs yield a sharp and clearly detailed picture, even on screens with diagonal measurements of 40 inches or more.
To put the difference in picture quality in numerical terms, most VHS tapes yield 240 lines of resolution.
By contrast, the videodisc carries about 430 lines, which accommodate more picture detail and increase sharpness by about 60 percent.
Another factor contributing to the current videodisc vogue is the new combination players, known as combi players.
No bigger than a conventional LP turntable, these ingeniously designed units can play both videodiscs and ordinary sound-only CDs. Consequently, they are the logical centerpiece for the increasingly popular systems in which sight and sound are combined into what is called a home theater.
These players can handle CDs as well as videodiscs because both are optical recordings -- i.e., the signal is recorded and reproduced by a beam of laser light. This entails yet another advantage: The disc is infinitely durable.
Since nothing but the weightless light of the laser touches the disc's surface, there is no friction and no wear.
Unlike videotapes, videodiscs don't suffer loss of picture quality from repeated use. Moreover, the disc carries a digital soundtrack that offers the tonal fidelity in video programs normally heard only on a CD stereo system.
Price has also contributed to the rising popularity of discs. At about $30 for a videodisc containing a full-length movie or other entertainment feature, the cost is far less than that of most prerecorded programs on videocassettes.
One reason discs are less expensive than tapes is that the discs are cheaper to manufacture. They can be duplicated quickly by a molding process, while each tape must be individually recorded.
The latest crop of combi players boasts technical refinements that make the disc option even more attractive.
One is a digital frame memory, to be found on some of the most sophisticated models, such as Panasonic's LX-1000 or Pioneer's CLD-3080, both priced at $1,400.
The frame memory lets the viewer freeze and store any single frame and display it as a still picture.
Even without this frame memory, freezing a single frame was possible with the earlier videodiscs, because they devoted a single turn of the disc to each frame.
To show a single frame, the laser simply had to scan the same turn over and over -- rather like the needle stuck in the groove of an old phonograph record.
But to gain added playing time, the more recent discs pack several frames into a single turn. Repeating a turn would therefore no longer reproduce a single frame.
That is why these longer-playing new discs make it necessary to extract the single frame from the sequence and store it in a memory to achieve still displays.
Today's longer-playing discs can accommodate a two-hour feature on a single platter, but it has to be turned over at the halfway point -- also like the old-fashioned LP record.
To avoid this inconvenience, Pioneer and Panasonic have come up with several combi units that automatically play both sides of a disc in sequence with only a brief interruption.
In Panasonic's new LX-200 ($850) the laser travels from one side to the other in just 11 seconds -- about half the time needed in most of the earlier models.
Even some of the less expensive combi players now provide outstanding performance and advanced operating features.
With equipment like this, it seems that video on discs is an idea whose time, at long last, has come.