DVD

The DVD (common abbreviation for Digital Video Disc or Digital Versatile Disc)[8][9] is a digital optical disc data storage format invented and developed in 1995 and released in late 1996. The medium can store any kind of digital data and was widely used for software and other computer files as well as video programs watched using DVD players. DVDs offer higher storage capacity than compact discs while having the same dimensions.

DVD
The data side of a DVD manufactured by Sony DADC
Media typeOptical disc
EncodingDVD-ROM and DVD-R(W) use one encoding, DVD-RAM and DVD+R(W) uses another
Capacity4.7 GB (single-sided, single-layer – common)
8.5 GB (single-sided, double-layer)
9.4 GB (double-sided, single-layer)
17.08 GB (double-sided, double-layer)
Up to four layers are possible in a standard form DVD.
Read mechanism300–650 nm laser, 10.5 Mbit/s (1×)
Write mechanism650 nm laser with a focused beam using more power than for reading, 10.5 Mbit/s (1×)
StandardDVD Forum's DVD Books[1][2][3] and DVD+RW Alliance specifications
Developed bySony
Panasonic
Philips
Toshiba
DimensionsDiameter: 12 cm (4.7 in)
Thickness: 1.2 mm (0.047 in)
Weight16 grams (0.56 oz)
UsageHome video (replaced by HD-DVD and Blu-ray), Computer data storage
Extended fromLaserDisc
Compact disc
Extended toDVD+RW, DVD-RAM (Fixed-track writable media)
HD DVD
Blu-ray
ReleasedNovember 1, 1996 (1996-11-01) (Japan)[4]
January 1997 (1997-01) (CIS and other Asia)
March 24, 1997 (1997-03-24) (United States)[5][6][7]
March 1998 (1998-03) (Europe)
February 1999 (1999-02) (Australia)

Prerecorded DVDs are mass-produced using molding machines that physically stamp data onto the DVD. Such discs are a form of DVD-ROM because data can only be read and not written or erased. Blank recordable DVD discs (DVD-R and DVD+R) can be recorded once using a DVD recorder and then function as a DVD-ROM. Rewritable DVDs (DVD-RW, DVD+RW, and DVD-RAM) can be recorded and erased many times.

DVDs are used in DVD-Video consumer digital video format and in DVD-Audio consumer digital audio format as well as for authoring DVD discs written in a special AVCHD format to hold high definition material (often in conjunction with AVCHD format camcorders). DVDs containing other types of information may be referred to as DVD data discs.