Difference Between Optical Discs And Magnetic Tapes
Videodiscs can be mass-produced like phonograph records and are therefore less expensive than videocassettes for prerecorded programs such as movies and music. In addition, they offer superior sound fidelity. Since there are no home recording systems for videodiscs, however, they cannot be used for recording television programs at home or making home movies.
Professional recorders, both optical disc and magnetic tape, provide nearly instantaneous playback of what is being recorded. This makes it possible for the operator to monitor the recording continuously to verify that recording is taking place and that its quality is satisfactory.
Both home and professional discs can provide random access to stored material. The disc pick-up head can be directed almost instantly to a particular track on the disc to find and display a particular item—a specific picture or a specific encyclopedia article, for example. VCR’s must search sequentially through tape until they find the desired item.
One of the main advantages of magnetic tape over optical discs is that it can be recorded, erased, and rerecorded an indefinite number of times with relatively inexpensive equipment. In addition, a single tape can hold up to eight hours of programming, compared to one hour on a two-sided videodisc. Because of these features, VCR’s are popular for making home movies with a television camera, and even more popular for automatically recording television programs in order to replay them later at more convenient times. Because there is no inexpensive method for making many copies of a master tape, preprogrammed cassettes cost more than videodiscs.