DVD-R DL

DVD-R DL (DL stands for Dual Layer), also called DVD-R9, is a derivative of the DVD-R format standard. DVD-R DL discs hold 8.54 GB (7.96 GiB) per side by utilizing two recordable dye layers, each capable of storing nearly the 4.7 gigabyte (GB) (4.38 GB) of a single layer disc -almost doubling the total disc capacity. Discs can be read in many DVD devices (older units are less compatible) and can only be written using DVD-R DL compatible recorders. It is part of optical disc recording technologies for digital recording to optical disc.

DVD-R DL has compatibility issues with legacy DVD-ROM drives known as pickup head overrun. To avoid this issue, the two layers of the disc need to be equally recorded. But this is a contradiction with the sequential nature of the DVD recording. Thus DVD Forum under Pioneer's lead developed a technology known as Layer Jump Recording (LJR), which incrementally record smaller sections of each layer to maintain compatibility with DVD-ROM drives.