The MPEG Multimedia Description Schemes (MDS) Group has produced a skeletal working draft for MPEG-21 Part 5 "Rights Expression Language (REL)," based upon initial work at the 58th MPEG Meeting in Pattaya, Thailand. Following receipt of several submissions in response to the MPEG Call for Proposals for a Rights Data Dictionary and Rights Description Language, three MPEG experts selected ContentGuard's Extensible Rights Markup Language (XrML) as a basis for the MPEG-21 Rights Expression Language. XrML [submission M7640] was selected as "the base architecture," and the working group is now conducting a series of Core Experiments to determine whether modification and additions will be necessary to fully meet the MPEG-21 requirements. Working group participants anticipate that they will have a fairly "stable specification" by July 2002; after subsequent formal review, comment, and voting procedures, they hope to publish the specification as an ISO/MPEG standard by June/July 2003.

MPEG-21 Rights Expression Language Working Draft. Information Technology -- Multimedia Framework -- Part 5: Rights Expression Language -- Working Draft. From: MPEG Multimedia Description Schemes (MDS) Group. December 07, 2001 [Pattaya, Thailand]. 15 pages. Reference: ISO/IEC JTC 1/SC 29/WG 11/N4533, ISO/IEC WD 21000-5. International Organization For Standardization, ISO/IEC JTC 1/SC 29/WG 11, Coding Of Moving Pictures and Audio. Summary:

Rights Expression Language (REL): "This working draft has been produced following the 58th Meeting in Pattaya, December 2001. During this meeting submissions to the CfP (N4335) and Requirements (N4336) where evaluated. This evaluation process included review and comment by three independent MPEG experts. As a result of the comments from these experts one submission for the REL was selected as the working model for further work. The submission selected was M7640 from ContentGuard. The process of review during the Pattaya meeting determined that while M7640 was best suited as the model to go forward the experts express concerns that elements of M7640 needed to be further evaluated to identify modification and additions to this REL to fully meet MPEG's requirements. A series of Core Experiments will be undertaken between the 58th and 59th meeting to facilitate this process of modification and addition.

Semantics of the REL: "The working assumption for the semantics of the REL is that these semantics will be based on the specification of M7640. The semantics will be modified and added to as a result of the ongoing development process of this standard."

Syntax of the REL: "The working assumption for the architecture of the REL is that this architecture will be based on the specification of M7640. The architecture will be modified and extended as a result of the ongoing development process of this standard. Editor's Note: Concerns to be addressed. These include but are not limited to: (1) Default interpretation of the element implicitly specified by the context; (2) 1-to-1 relationship between Semantic entities and syntactic elements; (3) Expression of UID; (4) Expression of roles; (5) Sequencing; (6) Inheritance of rights and permissions."

In the judgment of some experts, broad adoption of MPEG-21 REL is uncertain, due to a large number of competing "digital rights" efforts, the complexity of XrML, and the extraordinary sweeping claims made by ContentGuard with respect to patents on underlying XrML technologies.