MPEG-21's Aim: A Standard for Structure

Over the years, the Moving Pictures Expert Group has produced a foundation of standards on which audio and video entertainment content can be built. Now, it's working on a standard that could be the basis for the entire digital-content structure.

MPEG-21 proposes an overarching standard that would knit together the delivery technology and digital-rights protection for MPEG-based audio and video on any platform, for any device. But as is the case with MPEG-4, its just-released sibling, there's already some doubt about industry acceptance.

Don't panic — you haven't missed new MPEG iterations beyond MPEG-4. MPEG-21 has been tabbed as the standard for the 21st Century — not the 21st version of the media standard developed by the joint working group of the International Organization for Standardization and the International Electrotechincal Commission.

It's still a work in progress — most of MPEG-21's elements are set for completion in 2003 and 2004.

"It's really our effort to help the multimedia industry deploy the audio-visual standards in a logical and interoperable fashion," said U.S. MPEG Committee chairman Peter Schirling, senior consulting engineer for digital-media standards at IBM Corp.'s research division. "We saw so much divergence in end-to-end deployments, so what we are really trying to do is to help with the life cycle."

In a nutshell, MPEG-21 will provide several tools to manage how digital objects — such as audio, video or multimedia files — are encoded, secured, transmitted and viewed. The tools offer means to identify content, to manage how it is searched, cached, archived and retrieved and to manage how to adjust the display to fit myriad end-user devices.

Unlike prior iterations, MPEG-21 is designed to work with its predecessors. Elements of MPEG-21 archiving information can be included in an MPEG-2 stream, for example.

While MPEG-21 is wide-ranging, the element that's received the most notice is the Intellectual Property Management and Protection tool, which can set how and where content can be viewed. MPEG-2 and MPEG-4 both contained some conditional-access elements, but MPEG-21 provides a more universal framework for digital content protection.

First, MPEG-21 provides guides for protecting the content from being consumed at any point unless a user has the mechanism required to unlock it. Second, it offers a rights-expression language, so content providers can literally spell out how and where they want the content to be viewed.

But MPEG-21 may contract the same problems now plaguing its older sister, MPEG-4: Criticism that required royalties will stunt adoption, as well as concerns that it has been out-evolved by products already on the market.

For streaming-media giant Real Networks Inc., MPEG-21 is an interesting standards development, but there are still plenty of questions, said general manager of media-commerce applications Ji Shen.

"We want to see successful industry standards come out, however, the current path MPEG-21 goes down is leading to complex technology framework, and it is not royalty-free," he noted. "Those combined, basically, in our opinion, do not facilitate a rapid adoption of DRM technology."