JVC has developed prototype read-only discs that can contain data stored in both the DVD and high-capacity Blu-ray Disc formats.

The discs contain three layers. The upper layer is a Blu-ray Disc layer with a capacity of 25G bytes. Below are two DVD layers with a combined capacity of 8.5G bytes, JVC said.

The company has not decided yet when the technology will be commercialised but says it may produce the discs itself.

The announcement comes a few weeks after Memory-Tech said it had developed discs that can store data in both DVD and a rival high-density format called HD-DVD (High Definition/High Density-DVD). The discs contain two layers, an upper DVD layer with a capacity of 4.7GB and a lower HD-DVD layer with a 15GB capacity. They will go into mass production late next year, Memory-Tech said.

Both companies claim their dual-format technologies will help Hollywood studios and other content providers transition to the new optical disc technologies, which are being developed to replace DVDs to store high-definition videos. They should also help to popularise the new formats for consumers and encourage them to purchase players compatible with the Blu-ray Disc or HD-DVD formats.

The Blu-ray Disc format is backed by 15 major international electronics and technology companies including Sony and Matsushita. JVC joined the Blu-ray Disc Association (BDA), a group responsible for promoting the format, in October.

HD-DVD is backed by Memory-Tech, NEC, Toshiba, and Sanyo.

JVC is also developing a higher-capacity disc that will have a 50GB Blu-ray layer and an 8.5GB DVD layer. It is not saying yet when it expects this technology to be completed.

The company will ask the BDA to have its combination disc technology accepted as a specification for future commercialisation. Approval is expected during the first half of 2005.