Digital TV in the U.S.

DTV and time zones

Some day, DTV owners will be able to record their pretty pictures digitally, either for their personal home libraries or for time-shift reasons, when viewing is more convenient than the broadcaster's schedule. When that day will arrive is anybody's guess, as much for political as technical reasons.

Regarding digital videocassette recorders (VCRs), politics is the hang-up. Until the entertainment and electronics industries agree on encryption technology that would protect copyrighted material from unauthorized duplication, electronics manufacturers are unlikely to offer digital tape recorders for consumer use. Why? Content owners will refuse to release desirable programming for digital transmission unless they are certain that home tapes cannot be replicated indefinitely.

Technical standards are in place to add DTV capability to the existing digital VCR-format, called D-VHS (where D stands for data). The new high-speed (HS) mode for HDTV (and SDTV multichannel broadcasts) has a data input rate of 28.2 Mb/s, enabling 3-1/2 hours recording time on the new DF¬420 VHS cassette.

The tape could also record 7 hours of digital TV programming at the standard (STD) rate of 14.1 Mb/s. The new specification, proposed by VHS licensor JVC ltd., Yokohama, Japan, also includes provision for a low-speed mode (LS) that has four selectable data rates, good for recording times from 14 to 49 hours. Copy-protection issues also impact availability of recordable or rewritable optical media, such as DVD. But for technical reasons, digital disk recorders are farther from the market. It is estimated that the disk would need at least 9-GB capacity to store a 2-hour movie in high definition. Currently, manufacturers are still working on a 4.7-GB rewritable DVD akin to today's prerecorded version, and capable of 2 hours at SD quality or 4 at a lower resolution.

Although most manufacturers deny they will offer digital recorders until copy-management and -protection are in place, Panasonic has repeatedly said that it will offer an under-$ 1000 D-VHS recorder as early as this spring. But the company notes that the deck will have a proprietary digital connector that communicates only with Panasonic DTVs. Most industry observers believe the technical issues relating to copy-protection will be settled by year end.

In the interim, current DTV owners of whatever brand will have to content themselves with analog tape recording; super VHS (S-VHS) decks with a theoretical 420 lines of horizontal resolution now sell for as little as $300. Even that, though, will fail with at least one DTV set on the market—the 55-inch widescreen rear projector from Korea's Samsung Electronics Corp. Though the company's DTV has a composite video output, only the analog telecast signals are available for recording. Bearing in mind Hollywood's concerns; if not overly cautious, Samsung routes the digital channels onscreen only, and does not downconvert them to analog for output for the set. —S.A.B.