We've seen the two sided CD/DVD format, but this next generation hybrid is a bit more sophisticated. The regular DVD and High Definition data are stored on the same side, but to different layers. This means that the top side is still available for coating and printing. The point of all this is of course to ease the transition away from DVDs to the new format.
The discs contain two layers, an upper DVD layer with a capacity of 4.7GB and a lower HD-DVD layer with a15GB capacity, says Masato Otsuka, general manager of Memory-Tech's engineering department.
Mass production will start in October or November next year, which is about the same time as the company plans to produce read-only HD-DVDs. The company has six lines that can each produce up to 700,000 of these kinds of discs per month.Source: PCWorld