DVD – [ Digital Video Disc | Digital Versatile Disc]

 DVD – [ Digital Video Disc | Digital Versatile Disc] 

Invented and developed in 1995, the DVD was released as a digital optical disc data storage format in late 1996. The medium can hold something very digital and was often commonly used as a video program viewed using DVD players for software and other computer files. DVDs provide greater storage capacity than compact discs, though they have an equal dimension.

History 

Before the DVD, there were several formats created to capture video on optical discs. David Paul and James Russel invented the optical recording technology in 1963 and first patented it in 1968.

Types of DVD Capacity

    DVD has three capacity types.

• DVD-5

• DVD-9

• DVD-10

 DVD-5 - A DVD-5 is a DVD with a single layer that holds up to 4.7 GB of content.

 DVD-9 - DVD-9 is a single-sided DVD with a dual-layer that holds up to 8.5GB of data.

 DVD-10 - DVD-10 is a two-sided DVD that contains data of up to 9.4 GBs

How to store data inside DVD

DVD (Digital Video Disc) is a data storage technology, such as CDDs (CD). A way of storing digital information (1's and 0's) using light to read information is visual data storage. Analog information is translated from the inside edge of the disk to digital information and then encoded.

Using pits, digital data is coded into the disk storage layer. For encoding CDs, a type referred to as EFM, eight-to-fourteen modulation, is used and EFMPlus is used for eight-to-sixteen modulation in DVDs.

The distinction between pits and pits for the representation of digital data contained in disks is called ground. In a disk, the holes are arranged and form a spiral pattern on the recording layer of the disc. The disc rotates in a circular motion within the player, while an optical head laser travels slowly outward and stays fixed on the pits.

When the laser beam hits the earth, the detector reflects it and holes scatter it away from the detector. The transition between the land and the pit corresponds to the optical bit stream's "1".

How to read data which inside DVD

·       The data stored inside a DVD is read by a laser-generated by a laser emitting diode. In the laser, the photoelectric cell absorbs reflection. The data is read from the interior to the sides.

·       When the laser hits the pit field, the photoelectric cell will not be reflected, changing its value to '0'. The laser beam that enters the pit areas is scattered by it.

·       As the laser beam reaches the land area on a DVD data track, it represents the photoelectric cell, changing its value to '1'. The depth of a pit area is about 120nm in size and the length of a pit is about 400nm, which reflects a single binary value. So, high precision and accuracy are required for this method.

·       Compared to the laser used in the data reading process on a CD, the laser or ray produced by the laser emitting diode has a shorter wavelength. This laser is also compatible when reading both CDs and DVDs.