DVD was developed in the early 1990's as a joint venture between Sony and Philips. The idea was to produce a mainstream alternative to the Laserdisc, which never really caught on beyond the hardcore home theatre market. DVD originally stood for Digital Video Disc but now means Digital Versatile Disc to better reflect its computer applications. A DVD can hold 268 minutes of information, compared with 74 minutes on a CD. DVDs can be both dual-sided and dual-layered, meaning that in effect a single disc can have 4 sides. One of the most useful benefits of this is that a studio could put both Pan-and-Scan and widescreen versions of a film on one disc. DVDs are capable of displaying about 480 lines of resolution while VHS tapes display about 230. This results in a much sharper and more detailed picture.
The relationship of a television screen's width-to-height is called the aspect ratio. The aspect ratio of a standard TV is 4:3, whereas a movie theater screen is 16:9. With DVD technology, there is a choice of aspect ratio. Choosing the Letterbox format presents video in a 16:9 ratio by creating black bars at the top and bottom of a standard 4:3 TV screen. Pan & Scan is 16:9 video reformatted to fit a 4:3 screen, Widescreen is 16:9 video for a 16:9 screen, and Full Frame is 4:3 video for a 4:3 display.
Most of the major features of a DVD player are universal. All can play music CDs. Chapter selection, on-screen menus, and choice of screen size are all standard attributes. Also, all of today's models will produce excellent picture quality and sound. Keeping in mind that the major benefits of a DVD player are found within the technology's innate format, additional features and capabilities should be understood before a purchase decision is made.
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