By Jeffrey Krauss, Digital copy cat and President of Telecommunications and Technology Policy

Now that the cable industry and the TV set makers have pretty much worked out their differences on interconnecting set-tops and digital TV sets, the remaining controversies deal with copy protection. Copy protection is important because it must be built into digital set-top boxes and digital TVs, or else the movie studios won't allow their products to be distributed over cable. But it's turning out to be complicated stuff, and I'm not sure how it will end, or when. Here's the status.

Lessons from digital audio

It turns out that the recording industry made big mistake in the early 1980s, when it agreed on a standard for digital recording of music on CDs. Although it could not have foreseen it at the time, the incredible cost reductions in hard drive storage, coupled with the explosion of the Internet, have radically changed the way recorded music is distributed. Digital audio CDs are recorded without any copy protection, and use a non-proprietary coding method. This means that anyone can transfer a song from a CD to a hard drive, re-encode it with MPEG MP3 audio compression coding, and send copies to anyone else.

The movie studios saw this, and four years ago, established a Copy Protection Technical Working Group (CPTWG, pronounced "sea-pea-twig," or maybe "sea-pee-twig"). After analyzing the expected evolution of digital video, they decided that the various interfaces that might carry programming content to the digital TV set had to be protected against unauthorized copying. And they decided that the programming crossing these interfaces would have to be encrypted.

There are two kinds of interfaces we are talking about here: the interfaces between the digital TV and devices such as set-tops and digital VCRs; and the interface for the replaceable security module.

Interfaces between digital devices

The CPTWG first requested proposals for copy protection to be used on the digital baseband interface between digital TVs and set-top boxes. This interface is known variously as IEEE 1394, "FireWire," the Home Digital Network Interface, EIA-775 and SCTE DVS 194. The initial proposals evolved into a single proposal from five companies (Hitachi, Intel, Matsushita, Sony and Toshiba) which has become known as the 5C copy protection system. The CPTWG movie studios have approved 5C, and only 5C. The cable industry standard, SCTE DVS 194, includes 5C.

TV set makers haven't made a decision, but they know that digital cable set-top boxes will have 5C, so they will probably use it as well, because otherwise, the video coming out of cable boxes won't be watchable. But nonetheless, they don't want copy protection used on free TV broadcast programming, because of time-shifting; they want consumers to have the freedom to record TV programs and watch them later. And at least some of the computer industry folks don't want prohibitions on the transmission of digital video across the Internet.

And that has led to the current impasse. The 5C technology is proprietary; it is owned by Hitachi, Intel, Matsushita, Sony and Toshiba, which I would characterize as four VCR manufacturers and a computer company. And they have said to CPTWG that they will license the 5C technology, so long as it is only used against copying of premium cable programming, pay-per-view movies, etc. But they won't allow it to be used against copying of TV programs or Internet transmission. And the movie studios won't agree. Meanwhile, the broadcasters have complained that this impasse is slowing the rollout of digital TV broadcasting, and blaming both the movie studios and the VCR makers. There are other interfaces to consider. TVs can be connected to set-top boxes and VCRs using other signal formats, such as wideband analog component video, and RF remodulation to 8-VSB. Virtually nothing has been done on defining copy protection methods for these interfaces. Some first-generation digital TVs are actually two components, a digita l set-top box that connects to a digital display monitor with the wideband analog component video. And for these digital TVs, that interface is unprotected, although for now there are no video recorders that can record wideband analog component video.

And the interface in set-top boxes and in digital TVs that supports the security module (the Point of Deployment or POD module) is also vulnerable to copying. In this case, work is pretty far along in defining a copy protection method, but not yet totally done. This interface is critical to the cable industry, which promised the FCC that replaceable security modules would be available next year to support retail sale of set-top navigation devices. In order to meet that deadline, manufacturers will have to make some guesses about the final specification.

With new technology, it always takes longer than originally anticipated. When there are parties with widely divergent interests, like movie studios and VCR makers, it takes even longer. And in this case, the cable industry and the broadcast industry are innocent bystanders.

E-mail: Jeffrey Krauss