Overview
ISO/IEC 21000-8:2008/Amd 3:2015 extends the MPEG‑21 multimedia framework Part 8 (Reference software) by adding reference software for the Contract Expression Language (CEL) and the Media Contract Ontology (MCO). This amendment documents implemented reference modules and web services that support contract creation, validation, conversion and contract‑based authorization for multimedia assets. It provides practical, deployable reference implementations intended to help developers and integrators adopt ISO/IEC 21000 Parts 20 and 21.
Key topics
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CEL Reference Software (Java)
- Implements modules for Contract Identification, Contract Validation, and Contract Check‑With (contract‑based authorisation).
- Validation is performed against the CEL schema; Check‑With returns structured results (e.g., OK, USER_NOT_FOUND, CONDITION_NOT_SATISFIED) with diagnostic messages.
- Includes test classes for module verification.
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MCO Reference Software (mco‑refsw web services)
- A set of CGI/XSL‑based web services deployable on an Apache HTTP server to provide an MCO working environment.
- Supports CRUD operations for OWL/XML‑serialized MCO documents, plus export, load, deliver, search, and check‑with services.
- Serialization and conversion support: OWL/XML, RDF/XML, and CEL/XML, with Java components (OWL‑API) for format conversion and MCO↔CEL conversions.
- Architecture details: HTTP server + CGI scripts + XSL utilities; SVG support recommended for contract presentation.
- System requirements and dependencies are listed (Linux/Ubuntu, tcsh, Apache, xsltproc, graphviz, Java 7+ for Java conversion components).
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Interoperability and conversions
- MCO export/load can convert between OWL/XML, RDF/XML and CEL/XML; conversion modules are described and included.
Applications
- Implementing contract‑aware multimedia platforms and digital rights management (DRM) systems that rely on MPEG‑21 contract semantics.
- Automated authorization and policy enforcement workflows where requests are checked against CEL contracts (e.g., content playback, distribution, licensing operations).
- Content management and publishing systems that need semantic contract modeling using the Media Contract Ontology (MCO) and machine‑readable contract exchange.
- Tooling and prototype development for standards conformance, interoperability testing and research in rights expression and semantic web for media.
Who should use this standard
- Software developers and system integrators building MPEG‑21 compliant DRM, rights management, or content distribution systems.
- Architects of digital asset management (DAM) and streaming platforms requiring contract expression and automated policy checks.
- Standards implementers, researchers and tool vendors interested in CEL, MCO, OWL/RDF serializations and conversion workflows.
Related standards
Open preview (PDF)Information technology — Multimedia framework (MPEG-21) — Part 8: Reference software — Amendment 3: Contract Expression Language (CEL) and Media Contract Ontology (MCO) Reference Software