Like Blu-Ray Recordable (BD-R) discs, Blu-Ray Dual Layer (BD-R DL) discs are designed to store large HD video and audio files. Using blue-violet laser technology, BD-R DL discs can handle up to 1080p resolution and multiple audio formats. The difference between BD-R and BD-R DL, lies in the storage capacity and construction of the discs.

A single-layer Blu-ray disc, which is roughly the same size as a DVD, can hold up to 27 GB of data -- that's more than two hours of high-definition video or about 13 hours of standard video. A double-layer Blu-ray disc can store up to 50 GB, enough to hold about 4.5 hours of high-definition video or more than 20 hours of standard video.