DVD Versus Blu-ray

The DVD and the Blu-ray Disc have been warring since the official release of the Blu-ray technology in June 2006. The two storage media are virtually identical in terms of shape, diameter, and weight but are quite different under the surface. Here’s how they compare.

DVD

The DVD, or "digital versatile disc", was invented by Philips, Sony, Toshiba and Panasonic in 1995 as an upgrade to compact discs (CD-ROM) for computers, as well as Video CD's, VHS tapes and laserdiscs in the entertainment industry.

DVD's come in a number of flavors. A DVD-ROM can only be read and not written nor erased. DVD-R and DVD+R discs are recordable but only once. Rewritable DVDs (DVD-RW, DVD+RW, and DVD-RAM) can be recorded and erased multiple times.

DVD players cannot play Blu-ray discs, though Blu-ray players are compatible with DVDs and CDs. DVD players also only support SD (standard definition), a lower resolution format compared to the HD (high definition) format supported by Blu-ray.



Blu-ray

Blu-ray Disc was developed by the Blu-ray Disc Association, a team made up of a number of technology companies, including Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson. It was officially released in 2006.

The name Blu-ray refers to the blue laser used to read the disc, which enables data to be stored at a greater density compared to the longer-wavelength red laser used for DVDs.

The main selling point for Blu-ray is the sharper and more vivid picture quality relative to the DVD. However, this improvement comes at a cost - Blu-ray movies often cost about twice as much as the same movie on DVD. Blu-ray players are also more expensive.

Storage Capacities

A single layer DVD can hold 4.7GB of data, more than 6 CD-ROMs. Dual layer DVDs have a storage capacity of 8.5GB. A Blu-ray disc has five times the storage capacity of a dual layer DVD, about 50GB. This increased storage capacity translates to better image quality, better sound quality, and more special features. Approximately 3 hours of SD video can be stored on a DVD. This compares to 23 hours of SD video or up to 8.5 hours of HD video on a Blu-ray disc.

Player Compatibility

Because a Blu-ray player is capable of playing back standard DVDs, your existing collection of DVDs will play in a Blu-ray player. This is a decided advantage for the continued growth of the Blu-ray market.

Other Considerations

The selection of movies available on DVD's is much greater than that on Blu-ray Disc. This is because DVD technology has been around for a longer time and DVD movies are less expensive. However, most new titles are now released on both DVD anbd Blu-ray Disc.

The Blu-ray Disc specification requires the media to be scratch-resistant. DVD's are not required to be scratch-resistant, but some companies do use a hard-coating for their more expensive DVD products.