DVD is an optical disc technology with a 4.7 gigabyte storage capacity on a single-sided, one-layered disk, which is enough for a 133-minute movie. DVDs can be single- or double-sided, and can have two layers on each side; a double-sided, two-layered DVD will hold up to 17 gigabytes of video, audio, or other information. This compares to 650 megabytes (.65 gigabyte) of storage for a CD-ROM disk.
DVD uses the MPEG-2 file and compression standard. MPEG-2 images have four times the resolution of MPEG-1 images and can be delivered at 60 interlaced fields per second where two fields constitute one image frame. (MPEG-1 can deliver 30 noninterlaced frames per second.) Audio quality on DVD is comparable to that of current audio compact discs.
- DVD-Video is the format designed for full-length movies that work with your television set.
- DVD-ROM is the type of drive and disc for use on computers. The DVD drive will usually also play regular CD-ROM discs and DVD-Video disks.
- DVD-RAM is the writeable version.
- DVD-Audio is a CD-replacement format.
- There are a number of recordable DVD formats, including DVD-R for General, DVD-R for Authoring, DVD-RAM, DVD-RW, DVD+RW, and DVD+R.
DVD was originally said to stand for digital video disc, and later for digital versatile disc. The current official stance of the DVD Forum is that the format should just be referred to as DVD.