Blu-ray Disc Association
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Blu-ray Disc Format

What Blu-ray Disc variants are available?
As with CD and DVD, Blu-ray Disc media comes in pre-recorded, recordable and rewritable variants. The pre-recorded disc is called BD ROM, and usually contains movies or re-issued TV shows in High Definition format. The recordable disc is called BD R, and can be used for archival of huge amounts of data or video. The rewritable disc is called BD RE, and offers the same large capacity in a disc format that allows for repetitive usage.

What is the capacity of a Blu-ray Disc?
All three Blu-ray Disc types come in two versions: single layer and double layer. A double layer disc may hold up to twice the amount of data or video compared to a single layer disc, and uses two independent layers placed on one side of the disc to store its information (refer to "Technical Info" on this web site for more information). A single-layer disc holds up to 25 gigabytes, while a double-layer disc holds up to 50 gigabytes of data, without the need to flip the disc.

Can Blu-ray Disc products play DVD and CD?
Although this is not a requirement of the Blu-ray Disc format, all Blu-ray Disc products will play their DVD and CD counterpart formats. Compare this to the ability of today's DVD players to play CDs. Most companies have developed laser components and pickup units being able to read CD, DVD and BD.

Can Blu-ray Disc products record DVD and CD?
Implementation of DVD or CD recording capability is a manufacturer's option. Currently, some Blu-ray Disc video products allow you to record DVDs as well. It is expected that most Blu-ray Disc PC drives will support the recording of CD, DVD and BD.

Can I play a Blu-ray Disc on my DVD player?
No. As DVD players use a red laser to read the information from a disc, they are not capable of reading the very fine pits of a Blu-ray Disc, which requires a blue laser. Furthermore, DVD-Video players lack the advanced technology to decode the High Definition picture from a Blu-ray Disc.