Software: 
Cartrivision
cassettes used 1/2 inch tape and a recording technique called
"skip-field", which was a technique employed by recording only every
third field and essentially playing it back three times to lengthen the
capacity of the tape cartridges. The
end product of this technique was a slightly hazy and jumpy picture. Cartrivision had over 100 pre-recorded
titles (black cassettes) available for sale through retailers such as
Sears. The cassettes for sale consisted
of sports programs, do it yourself, education and travel, etc. Cartrivision also ran a service called the
"Cartridge Rental Network".
These movie cassettes (red) had to be rented through a process that
usually involved receiving the tapes through UPS once they were ordered through
the retailer, and then returning them back the same way. Needless to say this was a lot of work just
to watch a movie and did not go over very well. Not only that, but the rental cassettes could only be viewed once
at home. They could only be rewound
using a special rewinding machine that only the retailers had. This was done to protect any profits that
might be lost by the movie studios to repeat viewings.
Cartrivision
also offered blank cassettes for sale for home recording. The Cartrivision recorder used either of two
sizes of tape cartridges. The smaller
cartridge contained sufficient tape for up to thirty minutes of playing time,
while the larger cartridge had a playing time of up to 114 minutes. Certain tape cartridges had bilingual or
stereo audio channels. In playing a
bilingual tape, the selection of one or the other language is made by
disconnecting the undesired channel through the insertion of a plastic plug
into one or the other of auxiliary audio outputs at the back of the
Cartrivision recorder. That leaves the
desired channel connected to the speaker of the television set.
The
Hardware:
The
Cartrivision video tape recorder essentially came in only one
configuration. The Cartrivision system
was built into 25” console color TV’s made by Admiral, Teledyne Packard Bell,
Emerson-Dumont, Sears, Roebuck Co., etc.
There was also a prototype stand-alone video tape recorder that was
developed but never went to market. One
of the accessories that you could buy for the Cartrivision was the
"Instant Replay TV Camera".
From Cartrivision literature this is how they described the camera –
“The Cartrivision system may be purchased today with an inexpensive black and
white television camera. This camera
performs a dual function. It makes
possible home movies with sound and instant replay. It may also be used for a home surveillance or closed-circuit
system”. There was also a microphone
offered for sale for use with the camera but this seems to be a somewhat rare
piece. The Cartrivision system was
capable of stereo audio output, but this was only possible with some of the
pre-recorded cartridges. Tapes recorded
at home were recorded in mono.
How It Works:
One of the criteria for the Cartrivision Video Tape Recorder was the ability to play full movies without interruption. No inexpensive VTR of the cassette variety had been developed that would play more than an hour program and most of them played far less lengthy programs. The approach was taken with the Cartrivision system of a “skip-field” concept, which would allow the recording of one-third of the information normally available in a television signal without any apparent effect to the viewer, and as a consequence up to 110 minutes of programming was available on one cartridge.
During
recording the tape moves at a fairly slow pace, 3.8 inches per
second, while the record head which is mounted on a rotating
scanner, moves past the tape at a very fast pace of 1200 rpm. The tape moves on a diagonal to the plane
of the scanner rotation. The end result of this recording process is a series of helical tracks each about 9.5 inches long. Each track represents one frame of video
information. The scanner disc
incorporates three heads approximately 120 degrees apart. Only No. 1 head records, but during playback all three heads are
utilized. The heads are mechanically
staggered causing each head to read the same track during one revolution of the
disc. The same field, though recorded
once, is therefore essentially repeated three times during playback. The three heads are electronically switched
so that output is produced only when the correct head is in tape contact.