Blu-ray Discs (BD) vs DVD

The new Blu-ray format has many things that set it apart from its predecessor, the DVD; you'll find a breakdown of the major advantages below.

Storage

Just as DVD meant a 5-10x increase in storage capacity compared to CD, Blu-ray Disc also increases DVD capacity by 5-10 times. With up to 50 GB available, you can have up to 9 hours of HDTV video on a Blu-Ray disc, or 23 hours of SDTV (standard) video. This is mainly due to the usage of a blue (rather than a red) laser and improved lens specifications, allowing for a much smaller focus laser beam which enables the recording of much smaller and higher density pits on the disc.

Audio is even more deep, with 7.1 channels of surround sound catered for. Blu-ray discs can support encoding in up to 24-bit/192 kHz for up to six channels, or up to eight channels of up to 24-bit/96 kHz encoding. As a comparison, even new Hollywood films are mastered in only 24-bit/48 kHz, with 16-bit/48 kHz being common for ordinary films.

Due to the fact that the data layer on a Blu-ray Disc is placed much "closer" to the laser lens than in DVD (or even the HD-DVD proposal), there is less distortion resulting in significantly improved tolerances, meaning that more precision and ultra high storage densities are made possible.

Cost

As a result of Blu-ray Disc being manufactured as a single substrate disc (unlike DVD), the manufacturing process does not involve the bonding of two substrates, resulting in less production material, a shorter production time and lower production costs per disc. At comparable volumes, Blu-ray Disc production costs are within 10% of DVD production costs, although a Blu-ray Disc offers 5-10 x the capacity. It is by far the cheapest format measured in cost per GB.

Durability

As the result of recent breakthroughs in the development of hard coating for Blu-ray Disc, the discs offer much stronger resistance to scratches and fingerprints than other existing and proposed formats. Standing up to scratches and dirt, the discs have been rigorously tested with steel wool scratching, ballpoint pen usage and even having a metal pizza cutter run deeply over their surfaces, which did not affect playback/recognition.

Added Functionality

All Blu-Ray players use Java technology to bring interactive menus on Blu-Ray discs, with more functionality than the static/video menus found on standard DVD. With network connectivity on devices hooked up to the Internet, it's possible to have updates from the movie studios, adding content such as additional subtitle languages, promotional features, and other items not included on the disc at pressing time.

Blu-ray Stats