New proposal levels vendors’ playing field

A crucial element of all digital media, especially in the emerging HDTV and high-resolution systems (HRS) industries, is how to label images and other data streams so that signals can be shared by different systems with minimal degradation and confusion.

In 11 months, a Society of Motion Picture and Television Engineers (SMPTE) task force reached a consensus on far-reaching implementations on these labels, called header/descripters. The proposal could support new standards to accommodate even inexpensive equipment (such as NTSC standard TVs and Apple II computers) presently incapable of decoding all possible data streams while allowing for technological advances in equipment (HDTV or high-resolution imaging) or recorded signals.

A powerful consensus. The committee, chaired by Will Stackhouse of the Jet Propulsion Lab, had representatives from the computer, the telecommunications and the imaging and video conferencing industries, as well as several MIT professors and consultants. It is this broad technical base that makes the committee’s consensus so powerful.

The committee settled on the use of the evolving ISO/CCITT Abstract Syntax Notation 1 (called ASN.1), which provides an extensible notation for describing data that is to be exchanged by transmission or storage.

Although started as a computer standard, it permits the same information to be interpreted in different ways within different technologies. As the committee’s final report says, “To the video industry, the information is a continuous video stream. To the telecommunications industry, the same information is a sequence of bits to be transmitted. To the computer industry, that sequence of bits is interpreted as data structures.”

Embedding structures. ASN.1 is much like an envelope containing a single video frame but allowing for the embedding of one or more data structures within another. The header identifies by number the encoding standard employed, specifies the data’s length, permits users to intercept data streams at random times and provides optional error-protection and encryption capability.

When Rita Brennan of Apple presented the task force’s recommendations to the Intellectual Property Task Force of the International Multimedia Association (IMA) on March 9, it was this ability to permit independent, formal definition of intellectual property protection, encryption, and other source-coding descripters that got the audience’s attention and approval.

What does it mean? This consensus has been called “the most important SMPTE implementation since the NTSC television standard was developed 40 years ago.” It means that the film, imaging, television, computer and telecommunications industries are converging on a means of sharing digital signals among media in compact, universal, extensible ways that take into account the inadequacies of some implementations while not slowing the move to higher resolution and bandwidth solutions.

It probably means that the digital television of the future will have a ‘386 or better CPU to handle these headers on the fly, and a three- or four-megabyte buffer to hold the frame as the header is being handled. In short, the television will become a computer.

UNTIL NOW, OUT OF THE LOOP

The computer and imaging industries have felt left out of the visual standards-making process with the SMPTE and FCC focusing on film and television for suggestions and implementation. But this SMPTE committee, and the work of the Committee for High Resolution Systems (which addresses the need for a digital video standard for HDTV), show that these industries are no longer taking a back seat to film and TV.

They have successfully pushed for the establishment of a High-Resolution Information Systems Advisory Board that was authorized by President Bush in February.

The act finds what many of us have known for years: that computers have increasingly sophisticated video and digital imaging signal processing capabilities; that the core technologies required for high-resolution imaging are similar to digital television, video, telecommunications and the computer industry; and that associated telecommunications and transportable storage media are generally designed to support digital interoperability similar to digital imaging products and services.

This advisory board, authorized to analyze a broad range of information on standards and protocols for “the interoperability and harmonization of electronic high resolution imaging, high definition television, and basic telecommunications services,” is a great platform to ensure that the imaging and computer industries are taken seriously in the digital standards and implementation arenas.

Tom Hargadon