Dual layer DVD recordable discs offer up to four hours of high quality MPEG-2 video, or up to 8.5GB of data on a single-sided disc with two individual recordable “layers.†Dual layer capable recorders will have the ability to record on the new dual layer DVD recordable discs, as well as on traditional single layer DVD discs and CDs too. Want more? Because a recorded dual layer DVD disc is compliant with the DVD9 specification, the discs are compatible with most consumer DVD players and computer DVD-ROM drives already installed in the market.
How Are Dual Layer Discs Recorded?
Single-sided dual layer recordable discs are constructed by one dummy polycarbonate platter base and the other one that contains a single organic recording layer. Dual layer recordable discs contain two organic dye recording layers (termed L0 and L1, respectively) between dual polycarbonate bases and semi-reflective metal layers separated by a transparent spacing layer. Single layer DVDs have a wobbled pre-groove molded into the polycarbonate base that controls the rotation speed of the disc and provide the addressing scheme for the disc. In a dual layer recordable DVD, each recording layer has its own wobbled pre-groove that controls rotation speed and addressing for that layer. However, the entire “table of contents†and system area of a dual layer recordable disc is contained only on the first recordable layer (L0).
