Sony DADC manual Main Features, Format and Specifications

Main Features

1. From CD to DVD

DVD, which stands for Digital Versatile Disc, is the next generation of optical disc storage technology. It is essentially an optical disc that can hold video as well as audio and computer data. This new optical disc can reach a capacity of up to 26 times the capacity of a CD-ROM and encompasses pre- recorded read only discs like DVD-Video, DVD-ROM, DVD-Audio, SACD and recordable formats like DVD-R, DVD-RAM, DVD+RW and DVD-R/W. For movie applications, a DVD can store full length movies in a high-quality digital video with surround sound in several languages and a wide range of interactivity as well as subtitles. Almost all DVD players and DVD-ROM drives are equipped with an additional laser diode or a special lens for playback capability of existing Audio CDs and CD-ROMs.

1.1. Format and Specifications

The DVD standard defines a disc that maintains the overall dimensions of the current Compact Disc. Therefore the backwards compatibility with existing Audio CDs and CD-ROMs was easier to realise. The table below demonstrates similarities and differences of CD and DVD.

	CD	DVD
Disc diameter	120mm	120mm
Disc thickness	1.2mm	1.2mm
Disc structure	single substrate	two bonded
		0.6mm substrates
Laser wavelength	780nm	650 / 635nm
Numerical aperture	0.5	0.6
Track pitch	1.µm	0.74µm
Shortest pit/land	0.83µm	0.4µm
length
Data layers	1	up to 4
Data capacity	approx. 650 MB	4.7 GB - 17.1 GB

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