The group behind the series of DVD+ formats has started standardization work on dual-layer rewritable discs with the aim of completing it before the end of this year, it said Friday.

Like other DVD dual-layer discs, the new discs under discussion by the DVD+RW Alliance will be capable of storing 8.5GB of data. That's enough space for about 4 hours of DVD-quality video, the group said.

Standardization of the format won't mean the immediate availability of products. It typically takes several months for companies to work new technologies into their products, so expect DVD+RW DL drives to arrive sometime in 2006.