DVD-R DL (Dual Layer) (Also Known as DVD-R9) is a derivative of the DVD-R format standard. DVD-R DL discs employ two recordable dye layers, each capable of storing nearly the 4.7 GB (4.38 GiB) of a single-layer disc, almost doubling the total disc capacity to 8.54 GB (7.96 GiB). Discs can be read in many DVD devices (older units are less compatible) and can only be written using DVD-RW DL compatible burners.

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.

Wikipedia information about DVD-R DL. This article is licensed under the GNU Free Documentation License . It uses material from the Wikipedia article 'DVD-R DL'