Record 49 hours at one go? Yes, in due time, says Steve Homer
A digital videotape format that will allow users to record up to 49 hours on one VHS tape has been announced by JVC. The system can also record six programmes simultaneously. JVC also suggests this technology could be used for computer multimedia applications, including games. Video recorders based on the technology should be available in the United States towards the end of next year.

Called Data-VHS, the system builds on existing VHS technology and requires only minor changes to the basic VHS set-up. Even the tape is the same as for S-VHS, the up-market version of VHS. Speaking in Japan, Hiroki Shimizu, general manager audio and video, said that the additional technology required for a D-VHS recorder would add some £250 to the cost of a standard VHS machine. That cost should drop rapidly if the system takes off.

At present, however, JVC proposes to use this technology only in a "bit stream" format. Here digital data will be stored on the tape and read off again in exactly the way it was recorded. This will be useless for today's TV transmissions.

To record video, you will need to be able to take a digital TV data stream, store it and then decode it through the digital TV decoder. So far the only place with a fully operational digital TV system is the United States. There, the digital satellite receiver would tune in to the desired channel and send the output to the video recorder, which would then store the programme you wanted to keep. If you had two receivers, you could tape two data streams from two channels. To play the tape back you would have to send the digital output through the decoder in the satellite receiver and the output from that device would go to the TV.

This is all rather clumsy and it is likely that a version with its own digital compression/ decompression electronics will be available some time after launch. By the end of 1996 this would be unlikely to add more than $100-$200 (£63-£127) to the overall price. This recorder would be able to record video from any source - analogue or digital, including today's TV systems. But this would bring D-VHS directly into conflict with a completely different type of digital video recorder format, Digital Video Cassette (DVC), which is backed by Sony, Philips, Thomson, Matsushita (owners of Panasonic), Toshiba and, perhaps surprisingly, JVC.

With JVC claiming the support of all these companies for its new format, it seems to leave DVC in some sort of limbo. Digital TV is due to start in France in October and could arrive in the UK in late 1996. What type of video recorder we will be using with that TV remains unknown.