Toshiba unveils 45GB HD DVD

Toshiba yesterday introduced a higher capacity version of its HD DVD blue-laser disc format to meet the challenge posed by rival optical storage system, Blu-ray Disc (BD).

The prototype holds 45GB, just shy of BD's 50GB storage capacity. But unlike BD, which requires only two 25GB data-storage layers to provide that capacity, the new HD DVD needs three 15GB layers.

The three-layer disc is single-sided, but comprises a single-layer HD DVD glued onto a dual-layer disc. That means it's going to cost more. Toshiba wheeled out disc makers Cinram and Memory Tech to say how the new disc would incur only "minimal" extra production costs. The trouble is, HD DVD production lines will still need to be upgraded, so supporting the new disc will eliminate some or possibly all of the production price advantage HD DVD has over BD. And the capacity is still 5GB less.

And the new disc will necessitate new players with laser read heads capable of focusing on the upper layer. This isn't rocket science - it's just an extension of what heads are already doing with dual-layer discs. But it will require work to ensure the head gets meaningful data out of the reflected light after it has been partially scattered by the two intervening layers. This will make the read heads more complicated, and so more expensive.

Toshiba will also need to get these into the market quickly if it's to avoid pissing off consumers saddled with HD DVD players that can't read the new, higher capacity discs that all the latest movies are shipping on. Early adopters may not care, but mainstream buyers will.

Still, the three-layer disc addresses the key concern over the HD DVD format: its ability to hold the longest-running movies - think The Lord of the Rings extended editions - in the HD TV format's highest resolution settings.

Toshiba said the 45GB disc has already won the approval of the DVD Forum, the DVD standard's governing body. The Forum has also approved Toshiba's dual-mode disc, which bonds a dual-layer DVD onto the back of a dual-layer HD DVD, allowing content providers to support current- and future-generation players with the same product. Toshiba announced the dual-mode disc, since when JVC has come up with a similar dual-mode BD. ®

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