When Were Video Tapes Introduced?
Video tapes were introduced in the years following the Second World War. The idea of storing information on magnetic wire was first put into practice by a Dane, Valdemar Poulsen, in 1900, but little was heard about it until the 1920s when magnetic tapes were made in the United States and Germany.
The recording of most television programs is done on magnetic tape or video tape. This technique produces good pictures which can be played back immediately without processing. The magnetic tape, two inches wide, is moved at a speed of 15 inches a second past a magnetic recording head which imprints, by means of electrical signals, a magnetized pattern of the sound and picture.
The tape is a band of plastic which has a film of magnetic iron oxide coating-one ten-thousandth of an inch thick-spread over one side of it. When the tape is played back, the changing magnetic fields of the pattern of iron oxide particles create weak currents which exactly correspond to the sound and picture which has been recorded.
Recording enables programs to be re-broadcast or edited. In sports television it is often used for the ‘instant replay’ or reproduction of a particularly interesting event during a live broadcast. Video recording is also employed in slow-motion and stop-action techniques.
Videotape is used in both video tape recorders (VTRs) or, more commonly, videocassette recorders (VCRs) and camcorders. Videotapes are also used for storing scientific or medical data, such as the data produced by an electrocardiogram. Because video signals have a very high bandwidth, and stationary heads would require extremely high tape speeds, in most cases, a helical-scan video head rotates against the moving tape to record the data in two dimensions.
Tape is a linear method of storing information and thus imposes delays to access a portion of the tape that is not already under the heads. The early 2000s saw the introduction and rise to prominence of high quality random-access video recording media such as hard disks and flash memory. Since then, videotape has been increasingly relegated to archival and similar uses.
With advantages in technology, videotape has moved past its original uses (original recording, editing, and broadcast playback) and is now primarily an archival medium. The death of tape for video recording was predicted as early as 1995, when the Avid nonlinear editing system was demonstrated storing video clips on hard disks. Yet videotape was still used extensively, especially by consumers, up until about 2004, when DVD-based camcorders became affordable at consumer level and domestic computers had large enough hard drives to store an acceptable amount of video.
Consumer camcorders have switched from being tape-based to tapeless machines that record video as computer files. Small hard disks and writable optical discs have been used, with solid-state memory such as SD cards being the current market leader. There are two primary advantages: First, copying a tape recording onto a computer or other video machine occurs in real time (e.g. a ten-minute video would take ten minutes to copy); since tapeless camcorders record video as computer-ready data files, the files can simply be copied onto a computer. Second, tapeless camcorders, and those using solid-state memory in particular, are far simpler mechanically and so are more reliable.
Despite these conveniences, tape is still used extensively with filmmakers and television networks because of its longevity, low cost, and reliability. Master copies of visual content are often stored on tape for these reasons. Particularly by users who cannot afford to move to tapeless machines. Professional users such as broadcast television were still using tape heavily in the mid- to late 2000s, but tapeless formats like DVCPRO P2, XDCAM and AVCHD, are gaining broader acceptance.
While live recording has migrated to solid state (Panasonic P2, Sony SR MASTER or XDCAM-EX), optical disc (Sony’s XDCAM) and hard disks, the high cost of solid state and the limited shelf life of hard-disk drives make them less desirable for archival use, for which tape is still used. As of 2016, some news and production camera crews still have cameras that use tape formats, even in HD.