TDK is reportedly developing 4 and 8 layer writeable and re-writeable Blu-ray discs. Since each layer of a Blu-ray disc is capable of holding 25GB of data, the discs would weigh in at 100 and 200 Gigabytes, respectively. According to the slides below, the 100GB discs will be capable of storing 10 hours or more of HD video. If this holds true, the 200GB disc will be a beast, holding approximately 20hours of high quality HD content. The slides also list write speeds. Do not be fooled by the seemingly petite single digit record speeds. They represent write speeds of 72 to 200 Megabytes a second.

The base of the disc is the plastic substrate which is followed by a reflective layer and a dielectric layer. The media is then topped off with the dielectric and reflective layers and a cover layer, in that order. Between the first and last 3 standard layers comes the first recording layer of the disc labeled "L0 recording layer." There are a total of 4 layers to the right and each layer. Layers L0-L3 are separated by a spacer layer to help the laser focus on the correct layer for reading and writing.