DVD Forum
Dual Layer recording allows DVD-R and DVD+R discs to store significantly more data, up to 8.5 GB, per disc, compared with 4.7 GB for single-layer discs. DVD-R DL was developed for the DVD Forum by Pioneer Corporation, DVD+R DL (formally known as Double Layer) was developed for the DVD+RW Alliance by Philips and Mitsubishi Kagaku Media (MKM).