TOKYO Victor Co. of Japan Ltd. (JVC) and Sony Corp. have allied to jointly develop the interface for the D-VHS recorder. The partnership will combine IEEE-1394-related technologies that Sony is promoting as i.Link with JVC's D-VHS format, with an aim to position the D-VHS recorder as the most practical digital-video recorder for home networks that use the 1394 serial interface.
The D-VHS format enables digital-video recording with 44-Gbyte capacity per cassette tapes of the same size as today's VHS format, ensuring full compatibility with that analog standard. One tape can record for 7 hours in standard-definition mode at a transfer rate of 14.1 Mbits/second, or for 3.5 hours in high-definition mode at 28.2 Mbits/s.
Though JVC proposed D-VHS as early as 1995, the standard's use has been limited to dedicated tuner built-in recorders for JVC's Ecostar line and for PerfecTV from Hitachi Ltd.
"Sony's participation will make it more certain that D-VHS will be the world de facto standard," said Hiroki Shimizu, senior managing director of JVC.
Katsumi Ihara, president of Sony's Home A&V Products Co., said, "Through the joint R&D, the two companies will combine D-VHS and i.Link interface technology to provide a means of digital recording for digital broadcasts in the world. Furthermore, we want to propose new usage of D-VHS on a digital network."
IEEE-1394 has already been adopted in the consumer realm for output of digital-video camcorders. But JVC and Sony plan to devise technology to send MPEG-2 data through the 1394 link, making it possible to connect D-VHS decks to set-top-boxes for recording digital broadcasts.
"IEEE-1394 defined the road of the signal, but what runs on that road has not been defined," said Takamichi Mitsuhashi, a Sony development engineer. "We will build a protocol to define what will be transmitted."
JVC, as the licensor of D-VHS, will provide the 1394-related technology to licensees. A total of 13 major VCR manufacturers have lined up behind D-VHS, with three companies Hitachi, Matsushita Electric Industrial Co. and Philips Electronics serving as technical advisers.
A place for tape
Consumer manufacturers, including Sony and JVC, are working on the next-generation disk system with a capacity of around 15 Gbytes, which they expect to be suitable for a home video-disk recorder. But that doesn't mean there's no place for tape.
"People said that tape had no future," said JVC's Shimizu. "But in terms of cost, tape media have an incomparable advantage. D-VHS will vitalize the huge asset of VHS that has already accumulated."
The D-VHS format features bit-stream recording, in which an input signal and output is stored as is scrambled data is left that way, without descrambling. This is one way to avoid copy-protection problems.
For 1394, Hitachi, Intel, Matsushita, Sony and Toshiba have proposed the Digital Transmission Content Protection scheme to prohibit illegal duplication. A 1394-equipped D-VHS deck will thus have ample copy protection.
"But to avoid later troubles . . . we are discussing with copyright holders ways to settle copyright issues" for D-VHS licensees, said Shimizu.
JVC plans to introduce a D-VHS recorder with the codeveloped 1394 interface by this summer in Japan. Introduction in overseas markets will follow soon as copyright hurdles are cleared. Sony has a similar marketing timetable, according to Ihara.