BD-RE Information

BD-RE (or Blu-ray Disc Rewritable) is a high capacity, high definition optical storage disc format that can withstand multiple erasing and re-recording. BD-RE comes in various storage capacities-a single layer holds 25GB or approximately 4 hours of HD footage and a dual layer disc holds 50 GB of data or approximately 9 hours of HD footage.

The basic construction of a BD-RE disc is similar to other Blu-ray disc formats with some exceptions to compensate for re-recording abilities. It starts with a spiral grooved polycarbonate substrate followed by an alloyed silver reflective layer to help the BD device's laser beam read data.

Blu-ray RE DiscNext, a phase changing alloyed recording layer that alters between crystalline and amorphous states is flanked by dielectric layers that remove excess heat from the recording element. The phase changing of the recording layer determines whether the data is read, recorded or erased. These layers are topped with a polycarbonate-based cover layer and a clear protective coating that prevents scratches and other damage.

A double layer BD-RE disc has a more involved construction process. It shares a grooved, polycarbonate substrate, a metallic reflective layer, a phase changing alloyed layer and a cover layer like the single disc. However, the double layer disc includes four dielectric layers, an additional phase changing layer to record data and a spacer layer. The spacer is a uniquely developed adhesive that reacts to pressure to imprint an additional groove track. The dual layered BD-RE is also protected by a clear, hard coating.

At 1x, a BD-RE will write at a speed of just over 90 minutes for a single layered 25GB disc and 46 minutes at 2x for 25GB. Higher writing speeds can also transfer data at speeds of 72Mbps.

The Blu-ray Disc Association has introduced four versions of its rewritable disc format thus far. Currently, consumers are using the third version out of four. BD-RE 3.0 includes backward compatibility features, a movie application format and an addendum of camcorder-sized BD-RE discs for home use.

The fourth and latest version outlined in 2010 boasts near-future storage capabilities of 100GB per BD-RE disc.

The price of current BD-RE discs is still relatively high, but some users may justify the cost by considering what they get for their money in terms of quality and storage. The prices for BD-RE range anywhere from $5 USD to $25 USD per disc.

Be sure to check out our pages on these other Blu-ray formats:

Blu-ray Overview
BD-XL Printable Blu-ray Blu-ray 3D

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