digital versatile disc
DVD formats include DVD-Video (often simply called DVD), DVD-ROM, and DVD-Audio. DVD-Video discs hold digitized movies or video programs and are played using a DVD player hooked up to a standard television receiver. In a sense, DVD-Video players are the successors to the videocasette recorders (VCRs) that play VHS tapes. DVD-ROM [ R ead O nly M emory] discs hold computer data and are read by a DVD-ROM drive hooked up to a computer. These disks can only be read—the disks are impressed with data at the factory but once written cannot be erased and rewritten with new data. DVD-ROM also includes recordable variations. DVD-R and DVD+R[ R ecordable] discs can be written to sequentially but only once. DVD-RAM [ R andom A ccess M emory], DVD-RW, and DVD+RW [ R e W ritable] discs can be written to thousands of times; they differ in their technical standards and, as a result, in the amount of information they can hold. Dual layer disks, such as DVD-R DL, record data on two different layers within the disk. Many DVD recorders can record in several different recordable DVD formats. Some recorders include computer hard drives that allow the user to record tens to hundreds of hours of material temporarily; the user can then select the material that will be transferred to a DVD. When DVD was released in 1996 there was no DVD-Audio format, although the audio capabilities of DVD-Video far surpassed those available from a CD; the DVD-Audio format was introduced in 1999.
The Columbia Electronic Encyclopedia, 6th ed. Copyright © 2012, Columbia University Press. All rights reserved.
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