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Videotape is a means of recording television
pictures and accompanying sound onto magnetic tape as opposed
to movie film. In virtually all cases, a helical scan video
head rotates against the moving tape to record the data in
two dimensions, because video signals have a very high bandwidth,
and static heads would require extremely high tape speeds.
Video tape is used in both video tape recorders (VTRs or,
more common, video cassette recorders (VCRs)) and video cameras.
Tape is a linear method of storing information, and since
nearly all video recordings made nowadays are digital, it
is expected to gradually lose importance as non-linear/random
access methods of storing digital video data are becoming
more common.
History
Professional and broadcast use
Open reel
The first practical professional videotape
machines were the Quadruplex machines introduced by Ampex
in the United States in 1956. Quad employed a transverse (scanning
the tape across its width) four-head system on a two-inch
(5.08 cm) tape, and linear heads for the soundtrack. The BBC
experimented with a high-speed linear videotape system called
VERA, but this was ultimately unfeasible. It utilized 1/2
inch (1.27 cm) tape traveling at 200 inches (5.08 m) per second.
Although Quad became the industry standard
for 20 years, it had drawbacks such as an inability to freeze
pictures, no picture search, and in early machines, a tape
could only reliably be played back using the same set of hand-made
tape heads, which wore out very quickly. Despite these problems,
Quad could produce excellent images. Unfortunately, very few
early videotapes still exist. The high cost of early videotapes
meant that most broadcasters erased and reused them, and (in
the United States) regarded videotape as simply a better and
more cost-effective means of time-delaying broadcasts than
the previous kinescope technology, which recorded television
pictures onto photographic film. It was the four time zones
of the continental United States which had made the system
very desirable in the first place. However, some early broadcast
videotapes have survived, including The Edsel Show, broadcast
live in 1957, and 1958's An Evening With Fred Astaire, the
oldest color broadcast videotape known to exist (the oldest
color videotape is the May 1958 dedication of the WRC-TV studios
in Washington, DC). Subsequent videotape systems have used
helical scan, where the video heads record diagonal tracks
(of complete fields) on to the tape.
The next format to gain widespread usage was
the 1" (2.54 cm) C-format videotape from the end of the
1970s onwards. It introduced features such as shuttling and
still framing, but the sound and picture reproduction attainable
on the format were inferior to Quad.
The first video cassettes
Then, in 1969, Sony introduced the first widespread
video cassette (prior formats had used open reels), the 3/4"
(1.905 cm) composite U-matic system, which it later refined
to Broadcast Video U-matic or BVU. Sony continued its hold
on the professional market with its ever-expanding 1/2"
(1.27 cm) component video Betacam family (introduced in 1982),
which, in its digital variants, is still among the market
leaders. Panasonic had some limited success with its MII system,
but never could compare to Betacam in terms of market share.
Going digital
The next step was the digital revolution.
Among the first digital video formats Sony's D1, which featured
uncompressed digital component recording. Because D1 was extremely
expensive, the composite D2 and D3 (by Sony and Panasonic,
respectively) were introduced soon after. Ampex introduced
the first compressed component recording with its Ampex DCT
series in 1992. Panasonic trumped D1 with its D5 format, which
was uncompressed as well, but much more affordable. JVC developed
the S-VHS-based D9 format, which compresses video data in
a way similar to DVCPRO.
For camcorders, Sony adapted the Betacam system
with is Digital Betacam format, later following it up with
the more low-cost Betacam SX and MPEG IMX formats, and the
semiprofessional DV-based DVCAM system. Panasonic used its
DV variant DVCPRO for all professional cameras, with the higher
end format DVCPRO50 being a direct descendant.
High definition
The introduction of HDTV production necessitated
a medium for storing high resolution video information. In
1997, Sony bumped its Betacam series up to HD with the HDCAM
standard and its higher-end cousin HDCAM SR. Panasonic's competing
format for cameras was based on DVCPRO and called DVCPRO HD.
For VTR and archive use, Panasonic expanded the D5 specification
to store compressed HD streams and called it D5 HD.
Consumer use
Home VCRs
The first domestic videocassette recorders
were launched in the early 1970s, but it was not until the
Japanese systems, Sony's Beta (1975) and JVC's VHS, were launched,
that videotape moved into the mass market, resulting in what
came to be known as the "videotape format war",
which VHS finally won. VHS is still the leading consumer VCR
format, since its follow-ups S-VHS and D-VHS never caught
up on popularity. It has, however, lost the battle against
the nonlinear and disc based DVD, and is slipping into obsolesence.
Camcorders
In camcorders, however, the field was more
diverse; early camcorders generally took full-sized VHS or
Betamax tapes, but the greatest popularity for some time shared
by the 8 mm video format (later replaced by Hi8 and its DV
hybrid relative Digital8) and VHS-C (compact) tape. MiniDV
is now the most popular format for consumer camcorders, providing
near-broadcast quality video and sophisticated nonlinear editing
capability on consumer equipment; however, though intended
as a digital successor to VHS, MiniDV VCRs are not widely
available outside professional circles. Sony tried to introduce
a new camcorder tape with MicroMV, but consumer interest has
been low due to the proprietary nature of the format and limited
support for anything but low-end Windows video editors. For
high definition, the most promising system seems to be the
new MiniDV-based HDV, which uses MiniDV media to store a roughly
broadcast-quality HDTV data stream.
There has been a trend, largely spearheaded
by Hitachi, Panasonic, and Sony, to sell consumer camcorders
based on DVD-family media, but professional users consider
DVD camcorders too limited for anything but casual use and
have remained with digital videotape
or switched to solid-state or hard disk storage.
What
is Videotape ? | Audio
& Video Tape Preservation |
Video
Tape Conversion to NTSC or PAL or SECAM | Save
a Videocassette |
How
to Get a Digital Video Recorder | How
to Buy a VCR | How
to Videotape Sports Action |
Transfer
Audio From a Videotape to a Computer | Transfer
Audio From a Videotape to a Cassette |
Transfer
Video Onto the Computer | How
to Program a VCR | Video
Tape Formats |
Video
Tape Time Comparisons | Tape
& VCR Tips | Camcorder
& Recording Techniques
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