The Difference Between Blu-ray and DVD

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.

The greater data storage capacity of a Blu-ray disc means that the disc is able to store images with higher resolution. Digital video images are composed of small points of color called pixels. The more pixels there are in a frame of video, the higher its resolution will be. The resolution of the video stored on an optical disc therefore depends on the amount of data the disc can store. A Blu-ray disc can store up to 128 gigabytes of data, although this level of storage is rare in practice. Most discs contain 25 to 50 GB.

By contrast, DVDs can store around 4.7 GB. As a result, Blu-ray discs can store high-definition images which are too large for DVDs to store. In addition to storing higher-resolution video, the superior data storage of Blu-ray discs also leads to improved sound quality. The Blu-ray disc represents a major improvement on the DVD format, both in terms of video and sound quality. When combined with an HD television and quality speaker equipment, Blu-ray brings the spectacle and excitement of the cinema into your home.

Be sure to check out our latest Blu-Ray Burning Software Reviews.

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BurnWorld Reviewer ...
Rob Boirun

Founding member of the BurnWorld network. We focus on the 'storage' industry which covers everything from optical disc burning (DVD, Blu-Ray), to Cloud Storage, to Hard Disk Storage.

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