MPEG-4 Standard Nears Primetime


After years of quiet development, backers of the MPEG-4 compression standard are moving ahead with plans for broad-based commercial applications.

That standard, backers said, will be used to deliver relatively high-quality video content over bandwidth-constrained networks such as the Internet. It could eventually be used across the full spectrum of transmission pipelines to the home, including cable plant.

Growing support for the Moving Picture Expert Group's MPEG-4 has become evident among a broad range of hardware manufacturers, software developers, content developers and even some network operators throughout this year.

That's been true particularly at recent trade events such as April's National Association of Broadcasters' NAB 2000 in Las Vegas, May's National Show in New Orleans and Streaming Media East last month in New York.

MPEG-4 encompasses two key components: a high-efficiency means of encoding low-bit-rate transmissions-generally under 1 megabit per second-and object-oriented coding that allows content developers to manipulate discrete objects within a compressed bit stream.

This could allow content developers to switch objects in a program stream-advertising on a sports-stadium facade, for example-or even to control access to programming by encrypting a crucial object, such as the ball in a soccer match.

MPEG-4 "is a key enabler for new content creation," said Willem de Zoete, president of Philips Home Access Solutions, a recently formed Philips Consumer Electronics Co. business unit targeting set-top-box-based home products and services.

Philips, in particular, plans to take advantage of the object-oriented-coding capabilities of MPEG-4. "We think the Internet and broad-band are coming together," de Zoete said, although Philips is looking at MPEG-4 for everything from dial-up-based services to broadband 1.5-mbps uses.

Philips is "in in-depth discussions with some of our customers on next-generation set-top boxes," he added, although the company is still working on development issues, "first to make sure that the technology works."

This could be complicated by the many flavors of MPEG-4-at least for object-oriented coding-under development by different supporters of the standard.

Even backers of MPEG-4 conceded that only the high-efficiency coding portion of the standard-aimed at optimizing low-bit-rate transmissions under 2 mbps-really exists as an international standard.

"We're seeing a lot of great possibilities, as well as difficulties, in bringing products to market," C-Cube Microsystems Inc. director of marketing for advanced media products Bob Saffari said. "There is no 'standard' [for object-oriented coding] to ensure interoperability."

Saffari cited C-Cube's concerns that different MPEG-4 product developers are working with proprietary implementations of object-oriented coding that may not be interoperable.

Still, C-Cube plans to integrate MPEG-4 decoding capabilities in next-generation versions of its MPEG-2 decoder chips coming out "within the next few years," Saffari said.

"We think that MPEG-4 is very important," he said, adding that particularly with content running at bit rates below 1 mbps, MPEG-4 can deliver near-broadcast-quality video resolution.

While the basic specification for object-oriented coding was set last year, authoring tools have been slow to emerge.

"The actual authoring side is something of a mystery," IBM Corp. senior consulting engineer and chairman of the U.S. MPEG committee Pete Schirling conceded, mostly because prospective authoring vendors have been reluctant to release proprietary information.

There are still unresolved questions on the amount of "resources" that will be required to process that data. There's been some discussion, Schirling said, on "capping and defining the number of objects and the complexity of the platform [in order to be] interoperable. There's probably going to be some industry initiative on interoperability."

That's one of the chief objectives of the MPEG-4 Industry Forum, which began formally operating at the end of May. The forum is also expected to address the lingering question of which patents are required to execute compliant MPEG-4 technology.

While most MPEG-4 backers appeared to be focusing on content delivery over the Internet, Schirling believes the standard will be used alongside MPEG-2 by the cable industry, as well.

"The cable industry is going to use MPEG-4 to deliver content over cable plant," he added, for "mass customization of advertising. With local demographics in the box, you can customize ads on arrival."

This apparently will require something of a selling job to cable-system operators. "MPEG-4 at this juncture is a creature of the Internet," Time Warner Cable chief technology officer Jim Chiddix insisted. "The main advantage of MPEG-4 [low-bit-rate encoding] is something we don't need. Because we have such great bandwidth, as we subdivide nodes, [the need for MPEG-4] isn't there."

Still, Chiddix conceded that the interactive capabilities that come with MPEG-4 are "interesting. [But] we're a ways away from doing that." That will come, he and other technologists familiar with MPEG-4 said, once tools are readily available and the standard is more firmly established.

Also in the works are several enhancements to the basic MPEG-4 standard aimed at fixing some of the holes in the original specification, as well as adding some enhancements. "It's not without errors," Schirling said of the standard. "Anything this broad is going to have some rough edges."

Among the amendments moving toward standards-committee adoption is a "flextime" method of delivering MPEG-4 content in portions over different transmission platforms. The content stream will then be reassembled and resynchronized for display.

Although the sweet spot for MPEG-4 transmissions is expected to fall into the 300- kilobit-per-second to 1-mbps data rate, the standard was designed for transmission rates as low as 14.4 kbps and as high as "hundreds of megabits per second" for digital-video production, Schirling noted.

"Virtual stations" will use MPEG-4 coding to produce content, which will then be re-encoded to MPEG-2 for transmission, he suggested.

At the other extreme, MPEG-4 will also be used to deliver very low-bit-rate content to wireless devices, such as next-generation PDAs (personal digital assistants) connected to cellular phones and other wireless networks.

At the heart of one initiative is San Diego-based Packet-Video Corp., which has developed the technology platform-encoding, server and device software-and has signed up two mobile-phone-service providers, more than 30 content developers and a small but influential group of component and device makers.

Content developers include Universal Pictures, Warner Bros., Sony Pictures Digital Entertainment, Reuters Media, Fox Sports and The Weather Channel's Web site.

Prospective device suppliers include Casio Inc., Compaq Computer Corp., Sanyo Electric Co. Ltd. and NEC Corp., with Texas Instruments Inc. and Intel Corp. both taking licenses for device ICs (integrated circuits).

Investors in the company include Philips, Intel, Reuters Group plc, Sony Corp. of America, Qualcomm Inc. and Time Warner Inc.

Initial market tests involve Sonera, Finland's leading mobile-phone-service provider and an investor in Packet-Video, and an unnamed U.S. cell-phone company. Packet-Video has also had discussions with several Asian mobile-phone-service providers, spokesman Don Reckles said.

Content for the trials and planned commercial deployments will be tailored to an expected family of portable devices with relatively small screens.

"We don't expect people to watch a two-hour movie, or even a 30-minute television show," Reckles said. Instead, content developers will likely focus on two- to five-minute video clips, including local news and sports, movie trailers and other short-form entertainment.

Although much of the content will have the same look and feel of Internet-based streaming media, all of it will be "part of integrated applications," Reckles said.

A movie application, he noted, might include trailers of movies, a map of local movie-theater locations and a transaction component for buying tickets. Although neither trial includes interactive applications, "e-commerce will be part of this," he added.

The frame rate and picture resolution will be limited to start, with 14.4-kbps CDMA (code-division multiple-access) cellular connections producing no better than three to four frames per second. Even the Sonera trial, using connections up to 43 kbps, delivers no more than eight to 12 frames per second.

The company's road map, though, scales all the way up to broadband-wireless connections once the infrastructure is in place.