What is a digital video disk?
Digital Video Disc (DVD), also sometimes known as Digital versatile Disk is an optical data disk that usually contains multimedia information - but can also be used for data. The DVD can hold between approximately 4.7 and 17 gigabytes (GB) of information depending on how many layers of data it has. There are several DVD formats that allow users to manipulate disk data in different ways.
The most common data recorded in digital video are multimedia files such as video or sound. Other disks of this type may contain data such as large databases or installation files for computer programs. Most users recognize DVDs to be used for movies and TV. These discs usually contain video files, audio tracks and a multimedia menu. The offer often allows users to choose from several monitoring options, such as playing alternative sound songs with a movie or browsing other shots.
Standard physical inLiquity for the digital video disk is 4.7 inches (12 cm) in diameter. The discs are usually circular and have a central hole where the DVD reader can insert a drum that turns it or spins. Some smaller discs called minidVDS have a diameter of 3.2 inches (8 cm). For the most part, the DVD is made of several layers of plastic, which a total of 0.05 inches (1.2 mm) in the thickness.
plastic layers that contain a digital video disk are usually pressed by a pattern of very small indentation. These bumps, arranged in a long line spirally from the center of the disk, usually contain all digital data. The DVD reader spins the disc to read these lines of the code.
Traditional compact discs (CDS) work in a similar way, but holds only 650 megabytes (MB) digital information, while a single -layer DVD can hold 4.7 gigabytes (GB) or about seven times more. This is mainly because the indentation of the data on DVDJs are smaller than those on the CD. DVD also ODThey open the standard of the MODEG Group (MPEG) standard for video compression format, known as MPEG-2 to allow even more data on the disk.
Many DVDs have more than one spiral of data. Some discs have the material printed on both sides. Another option is to create a multilayer disk. They have a standard printed data spiral, but are covered with another layer of data and both layers are separated by a thin semi -transparent layer of gold. Standard, multilayer, one -sided DVD can hold up to 8.5 GB and a multilayer double -sided disk can hold approximately 17 GB of data.
There are several DVD formats. Some discs are only readable . This means that companies that publish a digital video disk do not allow private users to manipulate them on it. These DVDs for reading are often encrypted, so users cannot create unauthorized copies of the disk.
Other army drives to be manipulated by private users. Some, usually known aso DVDs of DVD-reignable (DVD-R) drives allow individuals to store data on a disc only once. Discs labeled DVD Transferable (DVD-RW) often allow the user to store and delete data several times on the same disk.