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Video Recording
Video recordingVideo recording is the process by which visual images are recorded on some form of magnetic recording device such as tape or a video disc. In magnetic recording, an unrecorded tape is wrapped around a rotating drum that carries the tape through a series of steps before it leaves as a recorded tape. The actual recording of the tape occurs on a cylindrical device known as the head. The head consists of a coil of wire wrapped around a core made of ferrite (iron oxide). When a camera is focused on a scene, the visual images it receives are converted to an electrical signal within the camera. That electrical signal passes into the recording head. When the electrical signal reaches the recording head, it passes through the wire coil. When an electrical current passes through a metal coil, it creates a magnetic field. The strength of the magnetic field (called a flux) created depends on the strength of the electric current passing through the coil of wire. The strength of the electric current, in turn, depends on the intensity of the light received by the video camera. If the camera sees a bright spot, it produces a strong electric current, and the strong electric current produces a strong magnetic flux. When the camera sees a dim spot, it produces a weak electric current, and that weak electric current produces a weak magnetic flux. The strength of the magnetic flux produced by the head is recorded on the magnetic tape that passes over it. The magnetic tape consists of millions of tiny pieces of iron oxide, like very tiny specks of flour. When the tape passes through a magnetic field, the iron oxide particles line themselves up in the direction of the magnetic field. If the field is very strong, all of the particles will line up in the same direction. If the field is very weak, only a small fraction of the particles will be aligned in the same direction. The brightness or dimness of the scene being photographed, then, is eventually translated into many or few iron oxide particles being lined up on the recording tape. Video disk recordingMagnetic tape is satisfactory for recording visual images under most circumstances. However, it does have certain disadvantages. One disadvantage is the time it takes to locate and play back any given portion of the recorded image. An alternative to using tape for recording images is a video disk. A video disk is similar to a sound recording disk. It is a round, flat object covered with a thin layer of iron oxide. An incoming electrical signal is fed into recording heads posed above the rotating disk. As the signal is recorded on the disk, the recording heads move outward in a series of concentric circles away from the middle of the disk. Recording continues until the disk is filled. [See also DVD technology; Magnetic recording/audiocassette ] |
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"Video Recording." UXL Encyclopedia of Science. 2002. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "Video Recording." UXL Encyclopedia of Science. 2002. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1G2-3438100656.html "Video Recording." UXL Encyclopedia of Science. 2002. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3438100656.html |
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Videocassette Recorder
VIDEOCASSETTE RECORDERVIDEOCASSETTE RECORDER (VCR) is a device that records, stores, and plays back television programs on magnetic tape; VCRs are also used to play prerecorded commercial cassettes. Videocassette recorders for consumers evolved from models used by broadcast professionals. By the early 1970s, two competing types of VCRs were available: the Betamax format, produced by the Sony Corporation, and the VHS format, produced by the Matsushita Corporation. Although Betamax was widely acknowledged to be technologically superior, the consumer market ultimately abandoned this format because it lacked several desirable features, such as recording times that could accommodate movies and longer programs on a single tape. The introduction of the VCR not only transformed the television-viewing habits of Americans by allowing them to tape programs and time-shift their viewing; it also shook the roots of the powerful movie industry. Initially, industry leaders feared that the availability of recorded movies to be watched at home would cause Americans to leave theaters in droves. But their fears proved to be unfounded, and over the next decades the revenue from videocassette sales and rentals became a significant portion of the profits from Hollywood films. The introduction of inexpensive camcorders—movie cameras that use videotape recording—gave another boost to the popularity of VCRs as families used them to make home movies that they could later view on their television sets and share with relatives and friends. Videocassette recorders gave Americans new flexibility, privacy, and control in viewing television programs and movies. They were perhaps the first technology that enabled consumers to personalize their viewing experiences, a trend that continues to grow in importance. BIBLIOGRAPHYDobrow, Julia R., ed. Social and Cultural Aspects of VCR Use. Hillsdale, N.J: L. Erlbaum Associates, 1990. Gaggioni, H. P. "The Evolution of Video Technologies." IEEE Communications Magazine 25 (Nov. 1987): 20–36. Graham, Ian. Television and Video. New York: Gloucester Press, 1991. Wolpin, Stewart. "The Race to Video." American Heritage of Invention and Technology 10 (Fall 1994): 52–63. Loren ButlerFeffer See alsoElectricity and Electronics ; Film . |
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"Videocassette Recorder." Dictionary of American History. 2003. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "Videocassette Recorder." Dictionary of American History. 2003. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1G2-3401804403.html "Videocassette Recorder." Dictionary of American History. 2003. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3401804403.html |
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videocassette recorder
videocassette recorder (VCR), device that can record television programs or the images from a video camera on magnetic tape (see tape recorder ); it can also play prerecorded tapes. A VCR converts the separate audio and video portions of a television or video camera signal to magnetic flux variations to magnetize the tape. The video recording heads move in a direction almost perpendicular to the tape movement, resulting in tracks that run diagonally across the tape width and increasing tape capacity. A camcorder combines a video camera and VCR in a single handheld machine.
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"videocassette recorder." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "videocassette recorder." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-videocass.html "videocassette recorder." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-videocass.html |
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videocassette recorder
vid·e·o·cas·sette re·cord·er (abbr.: VCR) • n. a device that, when linked to a television set, can be used for recording on and playing videotapes. |
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Cite this article
"videocassette recorder." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "videocassette recorder." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O999-videocassetterecorder.html "videocassette recorder." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-videocassetterecorder.html |
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videocassette
vid·e·o·cas·sette / ˌvidēōkəˈset/ • n. a cassette of videotape. |
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"videocassette." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "videocassette." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O999-videocassette.html "videocassette." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-videocassette.html |
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VCR
VCR • abbr. videocassette recorder. |
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Cite this article
"VCR." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "VCR." The Oxford Pocket Dictionary of Current English. 2009. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O999-vcr.html "VCR." The Oxford Pocket Dictionary of Current English. 2009. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O999-vcr.html |
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VCR
VCR see videocassette recorder . |
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Cite this article
"VCR." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "VCR." The Columbia Encyclopedia, 6th ed.. 2011. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1E1-X-VCR.html "VCR." The Columbia Encyclopedia, 6th ed.. 2011. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1E1-X-VCR.html |
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VCR
VCRVCR. SeeVideocassette Recorder . |
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Cite this article
"VCR." Dictionary of American History. 2003. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. "VCR." Dictionary of American History. 2003. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1G2-3401804382.html "VCR." Dictionary of American History. 2003. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3401804382.html |
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Vcr
Vcr Vancouver
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Cite this article
FRAN ALEXANDER , PETER BLAIR , JOHN DAINTITH , ALICE GRANDISON , VALERIE ILLINGWORTH , ELIZABETH MARTIN , ANNE STIBBS , JUDY PEARSALL , and SARA TULLOCH. "Vcr." The Oxford Dictionary of Abbreviations. 1998. Encyclopedia.com. 26 May. 2012 <http://www.encyclopedia.com>. FRAN ALEXANDER , PETER BLAIR , JOHN DAINTITH , ALICE GRANDISON , VALERIE ILLINGWORTH , ELIZABETH MARTIN , ANNE STIBBS , JUDY PEARSALL , and SARA TULLOCH. "Vcr." The Oxford Dictionary of Abbreviations. 1998. Encyclopedia.com. (May 26, 2012). http://www.encyclopedia.com/doc/1O25-Vcr.html FRAN ALEXANDER , PETER BLAIR , JOHN DAINTITH , ALICE GRANDISON , VALERIE ILLINGWORTH , ELIZABETH MARTIN , ANNE STIBBS , JUDY PEARSALL , and SARA TULLOCH. "Vcr." The Oxford Dictionary of Abbreviations. 1998. Retrieved May 26, 2012 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O25-Vcr.html |
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