Most of the current video recording devices are still analog recorders, but this is changing rapidly as hand-held digital video cameras, digital video discs (DVDs), and other digital video technologies capture increasingly large segments of the consumer market. The broadcast television market is also shifting rapidly to digital signal standards. Digital recording requires high-density recording technology due to the large bandwidth—125–270 million bits per second—but has many advantages over analog recording, including greater reliability, low cost (given recent advances in digital-signal-processing technologies), higher resolution, and greater color accuracy. Digital video has the additional virtue of transferability, as it may be recorded on any medium capable of storing digital data: computer hard drive, digital videotape, optical disc, or other. Given contemporary standards for memory and processing speed in affordable desktop computers, both professional and amateur video users can now upload digital video into working computer memory and edit it at will. There is little doubt that analog television signals, both for broadcast and recording, will be a thing of the past within some 10 or 20 years; indeed, in May, 1997 the U.S. Federal Communications Commission (FCC) mandated that U.S. broadcasters begin to phase out NTSC in favor of digital television.
Unfortunately, there is presently even more global disparity among digital television signal types than among analog signal types. The most pervasive—used on DVDs, streaming video on the Internet, and in broadcast—is probably that which exploits the type of data compression termed MPEG. This acronym is itself compression of "motion-JPEG," where JPEG stands for Joint Photographic Experts Group, the name of the body that designed this compression algorithm. Data compression enables the number of bits in a video frame to be reduced by as much as 75% without (hopefully) compromising the image quality. Image compression can, however, degrade image quality if misapplied. MPEG is actually two standards: MPEG-1 for low-quality video (e.g., streaming video on the Internet), while MPEG-2 is for broadcast-quality video.
Marsh, Ken. Independent Video: A complete Guide to the Physics, Operation, and Application of the New Television for the Student, the Artist, and for Community TV. Straight Arrow Books, 2001.
"Digital Television Frequently Asked Questions." U.S. Federal Communications Commission, 2002 [cited February 7, 2003]. <http://www.fcc.gov/mb/policy/dtv/>.
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