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CED in the History of Media Technology


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CBS EVR Prototype Player

1969: CBS EVR or Electronic Video Recording System Prototype

In the 1960's CBS and RCA rekindled their color TV standard competition of the prior decade in another form- the home video playback-only device. CBS called their system EVR for Electronic Video Recording and RCA's was called SV Holotape because it employed holography. In contrast to magnetic tape, these systems (in spite of the EVR acronym) were only capable of playing back a tape media that was mastered, and thus (in theory) would be cheaper to mass produce. CBS first announced their EVR system to the public in 1967. The above photo shows a prototype player in 1969.

EVR tape actually looked like unsprocketed 8mm film, i.e. a series of tiny images could be seen when the tape was held up to light. But these images were smaller than even 8mm film, as the tape had two sequences of images side-by-side along its length plus two outer audio tracks, one for each image sequence. During playback the tape reel was unspooled onto a reel inside the player while one row of images were displayed, then the tape was wound back onto the original spool while the other row was displayed. Electron beam recording was used to make the masters, and the finished tapes were read with a flying spot scanner and photomultiplier. The system was initially going to be offered in B&W (with a claimed horizontal resolution of 600 lines) and later in color.

Although EVR worked, the system couldn't be economically manufactured (at that time) due to the novel and expensive electron beam mastering. When CBS accountants analyzed it from this perspective, the tapes would cost $50 to $100 each to produce. CBS canceled further development of EVR in 1971 when Sony introduced the U-matic VCR with 60 minute tapes priced at $30 each.


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