by Rob Boirun for BurnWorld.com
Blu-ray and DVD are the two main forms of optical discs used to store digital video. DVD disks often come packaged with drivers for many IT solutions. Although the two types of disc operate on similar principles, important differences in their design mean that the Blu-ray disc has many advantages over the DVD.
Both Blu-ray discs and DVDs store data in a binary format, meaning that the data is stored as a string of ones and zeroes. These binary bits are represented by a series of reflective spots, or “lands”, and non-reflective spots, or “pits”, on the surface of the disc. These pits and lands are marked on the disc during manufacturing, typically with a laser. When the disc is placed in a player, another laser scans the rotating disc. When the laser is reflected, the device registers a 1; when it is not, it registers a 0. In this way, the digital information is read off the disc and transferred to the player, which translates the binary code into a video image.
The key difference between the Blu-ray and DVD formats is the type of laser used in the reader. The laser used in a DVD player has a greater wavelength, meaning that the pits and lands on a DVD are larger than the pits and lands on a Blu-ray disc. The Blu-ray system takes its name from the blue-violet laser used to read the discs. The shorter wavelength of this laser means that the pits and lands on the disc can be smaller. Because the pits and lands are smaller, the Blu-ray disc can have a larger number of them than a DVD, and consequently store larger amounts of data.
This excerpt is shared with permission from burnworld.com.
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