DVD Information

Digital Versatile Disc LogoThe term DVD is an acronym for Digital Versatile Disc or Digital Video Disc, and it refers to a type of optical disc used for storing data and video content. The capacity of a DVD is at least seven times greater than a compact disc and provides enough room for a full-length feature film. A DVD will support standard as well as widescreen television title views in 4:3 and 16:9 aspect ratios.

The DVD was introduced to a test-marketed U.S. in 1997 and developed by Toshiba, Philips, Sony and Time Warner. DVDs are a consumer-friendly format primarily used for home entertainment for all mediums, as well as for business needs, storage backup and computer software. DVDs took a strong reign over the global audio and video market by replacing videotapes, video cartridges and laserdiscs as the mainstream format within a decade of its debut.

DVD technology is akin to the next generation of the compact disc, as it mirrors its technology. Both discs share the same dimensions of 1.2mm thickness and 120mm diameter. The DVD contains microscopic pits of binary data on its polycarbonate layer like the CD, as well as substrate, adhesive, reflective and lacquered layers, but the DVD's construction has some singular exceptions.

The DVD's pits of data are smaller and rest closer together than those of a compact disc. This higher density of pits allows a shorter laser wavelength that in turn allows more data to be stored per track. The result is more efficiency in error correction and channel bit jitters. In addition the disc has a thinner outer layer to let the reading laser pass through the extra layers with more ease.

There are four basic constructions of the DVD depending on one's optical storage requirements: single-sided single layer, single-sided double layer, double-sided single layer and double-sided double layer. A shift by the drive's laser is all that is needed to read the next layer which therefore allows more storage per disc while eliminating the need to switch discs between projects or media entertainment.

Storage capacity does not completely double with the addition of another layer. Rather, the pits on the second layer must be constructed longer and less dense in order to combat obstruction and errors between layers. Dual layer and single layer DVD drives have comparable costs; however the recordable media itself still has a market separation.

To learn more about the different types of DVD formats, please use the links below:




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