An announcement from the Moving Picture Experts Group (MPEG) Convenor describes the advancement of important ISO draft specifications in ISO's MPEG-21 project. The goal of MPEG-21 is to "define a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities. Its scope is the integration of the critical technologies enabling transparent and augmented use of multimedia resources across a wide range of networks and devices to support functions such as: content creation, content production, content distribution, content consumption and usage, content packaging, intellectual property management and protection, content identification and description, financial management, user privacy, terminals and network resource abstraction, content representation and event reporting." The MPEG-21 Part 3 'Digital Item Identification' specification (DII ISO/IEC FDIS 21000-3) was elevated to Final Draft International Standard and will become an International Standard following a two-month ballot by JTC 1; DII supports the unique identification of digital items in the MPEG-21 framework. The MPEG-21 Multimedia Description Schemes Subgroup has completed Committee Drafts for MPEG-21 Part 5 'Rights Expression Language (REL)' and MPEG-21 Part 6 'Rights Data Dictionary (RDD)'. REL "specifies the expression language for issuing rights for Users to act on Digital Items, their Components, Fragments, and Containers"; RDD "forms the basis of all expressions of rights and permissions as defined by the MPEG-21 Rights Expression Language. The MPEG-21 REL and RDD work together to allow the machine-readable expression of rights associated with the use of multimedia. These parts will be finalized by MPEG over the next year."

Bibliographic information:

• Information Technology -- Multimedia Framework -- Part 5: Rights Expression Language. Committee Draft. Edited by Thomas DeMartini (ContentGuard, US), Xin Wang (ContentGuard, US), and Barney Wragg (UMG, UK). International Organization For Standardization. ISO/IEC JTC 1/SC 29/WG 11: Coding of Moving Pictures and Audio. Document Reference: ISO/IEC JTC 1/SC 29/WG 11/N4942. Text of ISO/IEC CD 21000-5. Date: 2002-07-26. From the Multimedia Description Schemes Group. Approved at the Klagenfurt, AT Meeting. 115 pages. Normative Annex A documents the REL Architecture; Normative Annex B provides the XML Schemas [Versioned '01' namespace: urn:mpeg:mpeg21:2002:01-REL-NS]; Informative Annex C documents the 'Relationship Between ISO/IEC 21000-5 (REL) and ISO/IEC 21000-6 (RDD)'.

• Information Technology -- Multimedia Framework -- Part 6: Rights Data Dictionary. Committee Draft. Edited by Chris Barlas and Godfrey Rust. International Organization For Standardization. ISO/IEC JTC 1/SC 29/WG 11: Coding of Moving Pictures and Audio. Document Reference: ISO/IEC JTC 1/SC 29/WG 11/N4943. Text of ISO/IEC CD 21000-Part 6. Date: 2002-07-26. From the Multimedia Description Schemes Group. Approved at the Klagenfurt, AT Meeting. 409 pages. Normative Annex A defines RDD StandardizedTerms; Normative Annex B provides Rules and Styles Guidelines for Textual Elements and Headwords; Normative Annex C specifies Requirements for the Registration Authority for the Rights Data Dictionary.

ISO/IEC 21000 consists of the following parts, under the general title Information Technology -- Multimedia Framework: [1] Part 1: Vision, Technologies and Strategy; [2] Part 2: Digital Item Declaration (DID); [3] Part 3: Digital Item Identification (DII); [4] Part 4: Intellectual Property Management Tool Representation and Communication System (IPMP TRACS); [5] Part 5: Rights Expression Language (REL); [6] Part 6: Rights Data Dictionary (RDD); [7] Part 7: Digital Item Adaptation (DIA); [8] Part 8: Reference Software.

From the Introduction of Part 5: Rights Expression Language:

This fifth part of MPEG-21 (ISO/IEC 21000-5) specifies the expression language for issuing rights for Users to act on Digital Items, their Components, Fragments, and Containers.

This document explains the basic concepts of a machine-interpretable language for issuing rights to Users to act upon Digital Items, Components, Fragments, and Containers. It does not provide specifications for security in trusted systems, propose specific applications, or describe the details of the accounting systems required. This document does not address the agreements, coordination, or institutional challenges in building an implementation of this standard. The standard describes the syntax and semantics of the language.

Clause 1 introduces this part of ISO/IEC 21000. Clause 2 gives the normative references. Clause 3 gives pertinent terms and definitions. Clause 4 gives the architecture of the REL followed by types and elements used to specify rights, resources, and conditions particular to multimedia.

Annex A delves into more detail on the REL architecture. Annex B gives the XML Schema definition of the types and elements defined throughout this part of ISO/IEC 21000...

Schema Conventions: The syntax of REL is described and defined using the XML Schema technology defined by the Worldwide Web Consortium (W3C). Significantly more powerful and expressive than DTD technology, the extensive use of XML Schema in REL allows for significant richness and flexibility in its expressiveness and extensibility.

To that end, a principal design goal for REL is to allow for and support a significant amount of extensibility and customizability without the need to make actual changes to the REL core itself. Indeed, the core itself makes use of this extensibility internally. Others parties may, if they wish, define their own extensions to REL. This is accomplished using existing, standard XML Schema and XML Namespace mechanisms.

Readers of these schemas should notice that a certain editorial style has, for ease of comprehension, been uniformly adopted. The XML Schema artifacts found within the REL core schema fall into three categories: attributes, elements, and types. The names of each have a different stylistic treatment: the names of types are in mixed case, with an initial capital letter, while the names of elements and attributes are in mixed case but with an initial lower case letter. For example, Grant is the name of a type, while grant is the name of an element and licensePartId is the name of an attribute.

The MPEG-21 Part 5 Rights Expression Language (REL) has a substantial dependence upon ContentGuard's XrML (Extensible Rights Markup Language) specification, as evidenced in the text and declared XML Schema namespaces (e.g., xmlns:sx="http://www.xrml.org/schema/2002/05/xrml2sx", xmlns:r="http://www.xrml.org/schema/2002/05/xrml2core"). We are led to understand that MPEG-21 Part 5 (REL) is [to be] the official XrML 'Content Extension' (superseding the XrML 'SX Content Extension' which was published in XrML 2.0 but omitted from XrML 2.1). See background in "ContentGuard Releases XrML Version 2.0 and Submits Specification to Standards Bodies." XrML is also being used as the basis for the OASIS Rights Language TC; see the MPEG WG11 [Class C] Liaison Statement to OASIS Right Language Technical Committee and posting which indicates that this Part 5 CD 'is out for National Body comments which are due 10-27-02'. [.DOC]

From the Scope statement of Part 6, Rights Data Dictionary:

The Rights Data Dictionary (RDD) comprises a set of clear, consistent, structured, integrated and uniquely identified Terms (as defined in Clause 3) to support the MPEG-21 Rights Expression Language (ISO/IEC 21000-5). Clause 5 of the MPEG-21 Standard specifies the structure and core of this Dictionary, and specifies how further Terms may be defined under the governance of a Registration Authority, requirements for which are described in Annex C.

Taken together, these specifications and the Dictionary and Database together make up the RDD System. Use of the RDD System will facilitate the accurate exchange and processing of information between interested parties involved in the administration of rights in, and use of, Digital Items, and in particular it is intended to support the MPEG-21 REL. Clause 6 describes how the RDD relates to the MPEG-21 REL.

As well as providing definitions of Terms for use in the REL, the RDD System is designed to support the mapping and transformation of metadata from the terminology of one namespace (or Authority) into that of another namespace (or Authority) in an automated or partially-automated way, with the minimum ambiguity or loss of semantic integrity.

The Dictionary is a prescriptive Dictionary, in the sense that it defines a single meaning for a Term represented by a particular RDD name (or Headword, see Clause 3), but it is also inclusive in that it recognizes the prescription of other Headwords and definitions by other Authorities and incorporates them through mappings. The RDD also supports the circumstance that the same name may have different meanings under different Authorities. The RDD has audit provisions so that additions, amendments and deletions to Terms and their attributes can be tracked.

RDD recognises legal definitions as and only as Terms from other Authorities that can be mapped into the RDD. Therefore Terms that are directly authorized by RDD neither define nor prescribe intellectual property rights or other legal entities.

Clause 6 of MPEG-21 Part 6 CD describes the 'Relationship between REL and RDD'. "There are four specific mechanisms by which Terms defined within the RDD may be represented in the REL: [1] REL defines a set of XML Schema Complex Types that, in the XML Schema sense, derive from (either extend or restrict) the conceptually abstract type Right (from the REL core namespace). Some of these types reside in the urn:mpeg:mpeg21:2002:01-REL-NS namespace. For convenience, in this Clause these types are called 'Multimedia Rights. Each activity has a context that can be related to particular ActType(s) within the RDD ontology. An activity is said to be within the scope of a particular Multimedia Right if the activity's context is a contextualization of the ActType corresponding to that Multimedia Right. The ActTypes corresponding to the Multimedia Rights are given in Annex A1. [2] RDD ActTypes other than those in the table above can be expressed using REL with XML Schema Complex Types that derive from the conceptually abstract type Right (from the REL core namespace). [3] RDD ResourceTypes can be expressed using REL with XML Schema Complex Types that derive from the conceptually abstract type Resource (from the REL core namespace). [4] RDD ContextTypes can be indicated using REL with XML Schema Complex Types that derive from the conceptually abstract type Condition (from the REL core namespace." See also the Informative Annex C of Part 5.

MPEG-21 Part 2 'Digital Item Declaration' describes "a set of abstract terms and concepts to form a useful model for defining Digital Items. Within this model, a Digital Item is the digital representation of 'a work', and as such, it is the thing that is acted upon (managed, described, exchanged, collected, etc.) within the model. MPEG-21 DID uses XML notation: The section on 'Representation' includes "normative description of the syntax and semantics of each of the Digital Item Declaration elements, as represented in XML; this section also contains some non-normative examples for illustrative purposes." The Part 2 section on Schema supplies the normative XML schema comprising the entire grammar of the Digital Item Declaration representation in XML. See from the MPEG announcement of May 15, 2002 [ISO/IEC JTC 1/SC 29/WG 11 N4733]: "Digital Item Declaration (ISO/IEC FDIS 21000-2) was elevated to Final Draft International Standard and will become an International Standard following a 2 month ballot by JTC 1. This is an important milestone as MPEG has now standardized a fundamental model for the transaction of any content that may be referenced, including multimedia content. Subsequent standards in the MPEG-21 suite will use and further enable this framework by specifying Digital Item Identification (DII), Intellectual Property Management and Protection (IPMP), Rights Expression Language (REL), Right Data Dictionary (RDD), Digital Item Adaptation (DIA) and the MPEG-21 Reference Software. These parts will be finalized by MPEG over the next two years..."