Science Fair Project Encyclopedia
Video cassette recorder
The video cassette recorder (or VCR, less popularly video tape recorder) is a type of video tape recorder that uses removable cassettes containing magnetic tape to record audio and video from a television broadcast so it can be played back later. Many VCRs have their own tuner and can be programmed to record the signal on a particular channel during a particular time interval.
Later model VCRs can record and play tapes both in Short Play (SP) format and in Long Play (LP) format. LP format increases the available recording time, at the loss of some signal quality. Some can even record/play in the Extra Long Play (EP, ELP, or SLP) format, which slows down the tape speed to about one third of SP.
Before the advent of the VCR proper, reel-to-reel VTRs were marketed by Sony, Ampex, RCA, Philips, and others. Most of these did not have timers, and were mainly used by schools and colleges to record educational programmes, and by businesses as a means of distributing training films. Even earlier, in the 1950s, British enthusiasts could buy home kinescope kits which allowed the filming of TV shows on 16mm film.
In 1958, Ampex took its color video tape recorder to Russia and demonstrated it before Vice President Richard Nixon and Nikita Khrushchev, Premier of the USSR. A color video recording was brought back to the US and seen on American television. RCA also had taken color television equipment and cameras to the USSR.
In the early 1970s the Dutch electronics company Philips developed a VCR system that used square cassettes with a recording time of one hour (the Video Compact Cassette system). The machines were equipped with crude timers that used rotary dials. The machines were expensive and the system never caught on.
It was not until the late 1970s, when European and Japanese companies developed more technically advanced machines with more accurate electronic timers and greater tape duration, that the VCR started to become a mass market consumer product. By 1980 there were three competing technical standards, with different, physically incompatible tape cassettes.
One, the Video 2000 or V2000 system, also from Philips dropped out of the running quite quickly. It worked well, and gave a good quality recording and playback, as it used piezoelectric head positioning to dynamically adjust the tape tracking. It was also notable in that its cassettes had two sides, like a record or audio cassette. However, V2000 hit the market after the other two rivals, and managed only limited sales in Europe before vanishing.
The two major standards were Sony's Betamax (also known as Betacord or just Beta), and JVC's VHS. Betamax was generally reckoned to make and play slightly better quality recordings and used smaller media, but VHS rapidly overtook it in sales.
As more VHS recorders came into use, and more VHS films became available, network effects eventually squeezed Betamax out of the consumer market, though a related system called Betacam still remains in use for high quality professional recording equipment.
Various reasons are given for the failure of the Beta consumer format:
- Some accounts claim that VHS won because it initially allowed for twice the recording time
- Others attribute the success of VHS to the greater availability of pornography on that medium, reflecting the long standing tradition of pornography being the driving force for the takeup of new media (the Internet being another obvious example).
- JVC and Sony used different marketing models for their technology: JVC licensed their VHS technology to consumer electronics companies like Zenith and RCA, which then produced low-cost VCRs, enriching JVC through royalties paid under its license. Fewer companies were licensed to produce Beta machines.
In the late 1990s and early 2000s, DVD gradually overtook the VCR as the most popular format for playback of prerecorded video. DVD Video Recorders and Digital video recorders such as TiVo have recently begun to drop in price in developed countries, signaling the end is near for VCRs in those markets.
Macrovision is a system that reduces the quality of recordings made from commercial video tapes, DVDs and pay-per-view broadcasts by adding random peaks of luminance to the video signal during vertical sync. These confuse the automatic level adjustment of the recording VCR which causes the brightness of the picture to constantly change, rendering the recording unwatchable.
When copying from a videocassette, the Macrovision-distorted signal is stored on the tape itself. By contrast, on DVDs there is just a marker asking the player to produce such a distortion during playback. All standard DVD players include this protection and obey the marker, though unofficially many models can be modified or adjusted to disable it.
The S-VHS format has been introduced in an attempt to breathe new life into the aging VCR technology, but it has not gained sufficient momentum in the consumer market due to the new digital video formats.
For home video recording, both Personal Video Recorders (such as TiVo and ReplayTV) and DVD recorders are becoming popular, although neither has yet supplanted the VCR. In fact, Tivo cooperates well with VCRs which can be used to archive PVR recordings. However, the introduction of recordable DVDs with sufficient recording capacity on to the regular market with their advantage of random access could spell the doom of the VCR once the price comes down significantly.
The main drawback with recordable DVD is not the technology itself, but of the disc formats. At present, no less than three different types of DVD recordable disc exist. These are DVD + (plus), DVD - (dash) (both in record once and rewritable versions) and DVD-RAM (which is always rewritable). All three are backed by different consumer electronics manufacturers, and none shows any sign (as of 2004) of gaining "critical mass" in the marketplace. Consumers wary of another format war (similar to the Betamax versus VHS debacle of the early 1980s), has meant that sales of consumer DVD recorders have been comparatively sluggish, although many recorders are now able to record onto both DVD+ and DVD- media.
Another important drawback of DVD recording is that one DVD is limited to two hours of recording if the quality is not to be significantly reduced, while VHS tapes are readily available up to 210 minutes (standard play) in NTSC areas and even 300 minutes in PAL areas. The advent of the recordable two-layer DVD in late 2004, if it gets widely adopted, will reduce this disadvantage.
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