This one is crazy. I never even heard of this format before today but it is pretty amazing.
The Capacitance Electronic Disc (or CED) was a disc-based videosystem, much like DVDs or more approximately Laserdiscs, but based on phonographic technology. In other words, it’s video on vinyl.
Perhaps that’s understating it as the technology, especially for the time, was pretty sophisticated. Developed by RCA between 1964 and 1972 (!!), political turmoil and R&D problems in developing the technology prolonged the consumer release of the product by 16 years. By the time the first CED players were released into the market in 1981, Betamax and VHS were fast taking control of consumers’ mindshare. CED players were discontinued by RCA in 1984, only three years after release.
There were a lot of problems with CED. First, the surface of the discs were sensitive to dust and oils from fingerprints. So the discs were encased in a protective plastic shell, not unlike the first Bluray prototypes.
Secondly, despite their huge physical size, the discs never managed to fit more than 60 minutes of video on a single side. Which means users would have to flip the disc if they were watching a movie. If the movie ran over 2 hours, users had to insert an additional disc! It’s like Final Fantasy 7 on Playstation.
But that aside, look at this thing. It’s amazing. 1964?? It even had random access like a CD, so you could skip ahead to parts, a remote to pause and stop, and stereo sound. Lightweight blows my mind.
The discs themselves are the same size as a 12″ record you would play on your Technics (11.8 inches) but they would spin at 450 rpms. From Wikipedia:
A keel-shaped needle with a titanium electrode layer rides in the groove with extremely light tracking force, and an electronic circuit is formed through the disc and stylus. The video and audio signals are stored on the Videodiscs in a composite analog signal which is encoded into vertical undulations in the bottom of the groove, somewhat like pits. These undulations have a shorter wavelength than the length of the stylus tip in the groove, and the stylus rides over them; the varying amount of air space between the stylus tip and the undulations in the groove under it directly controls the capacitance between the stylus and the conductive carbon-loaded PVC disc. This varying capacitance in turn alters the frequency of a resonant circuit, producing an FM electrical signal which is then decoded into video and audio signals by the player’s electronics.
Pretty revolutionary stuff and similar in the way a CD or other optical disc is read, sans laser. Changing the stylus tho is kindof a brick, and a requirement after many plays. And much like our vinyl records, the more you played a CED disc the more it would degrade. It would even skip and shit. The Lasderdisc of Phonographs!! But let it be said, even the superior Laserdisc had this storage limitation, despite being of equal size and optical.
Here’s the first few minutes of Star Wars running off of a CED disc to give you an idea of the picture quality. The author of the video notes that there is a “2.54% speedup so they could fit the movie onto a double sided disc,” so everything sounds a tad bit faster:
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