DVD has long overtaken VHS as the medium for recording TV and pre recorded films. How long will it be before DVD is superseded by the next development? Capacity is the issue here. The possibilities in terms of audio and audiovisual quality created by HDTV will require a medium with greater capacity than can be afforded by todays DVD disc.

The next generation of recordable media are being developed. Blu ray disc is currently being developed by a consortium of companies including Hitachi, LG, Samsung, Sharp, Sony and Thompson. Dell and Hewlett Packard are also supporting Blu ray disc technology. Blu ray disc has a capacity of 25GB per layer compared to DVDs 4.7GB.

This technology is being developed because of this greater capacity and this is being mainly driven by the expected explosion of high definition TV. The additional capacity will be nessercary to capture the enhanced quality feature of HDTV

At present Sony has launched a Blu ray recorder onto the Japanese market specifically for recording HDTV.

In parallel Toshiba and NEC are developing a rival format HD DVD, which although has less capacity than Blu ray (15GB) but the HD DVD is similar to Blu ray but the physical properties are closer to current DVDs and can be replicated on existing machinery. Blu ray on the other hand requires new manufacturing equipment.

Whether HD DVD or Blu ray disc become the established protocol remains to be seen, but either one could become the industry standard over the next few years.