ISO/IEC 21000-2:2005

Overview

ISO/IEC 21000-2:2005 - part of the MPEG-21 multimedia framework - defines the Digital Item Declaration (DID): a uniform abstraction and interoperable XML representation for declaring the structure, resources and metadata that compose a Digital Item. The standard covers three main deliverables:

• Model: an abstract set of terms and concepts for describing Digital Items (containers, items, components, resources, descriptors, fragments, anchors, statements, assertions, conditions, choice/selection, etc.).
• Representation: the Digital Item Declaration Language (DIDL) - normative XML syntax and semantics for DID constructs.
• Schema & Examples: informative XML Schema grammars and illustrative DIDL examples to aid implementation and interoperability.

Keywords: MPEG-21, Digital Item Declaration, DIDL, Digital Items, XML schema, multimedia framework.

Key Topics and Requirements

• Abstract DID Model: defines entity descriptions (container, item, component, resource, fragment, descriptor, statement, anchor, annotation, assertion, condition, choice, selection) to express structure and relationships.
• DIDL XML Representation: normative element definitions (, , , , , , , , , , , , , , , ), with syntax and semantics specified for consistent parsing and processing.
• Validation & Canonicalization: guidance on DIDL validation and canonical forms for consistent interchange.
• XML Schemas (informative): example schemas illustrating complete grammars for DIDL XML.
• Illustrative Examples: non-normative DIDL documents showing metadata interoperability and practical uses.
• Interoperability focus: aims to enable transparent use of multimedia across networks and devices.

Applications

ISO/IEC 21000-2:2005 is practical for anyone packaging, exchanging, or processing multimedia content and metadata:

• Content providers & publishers using DIDL to declare multimedia packages (audio, video, images, timed media).
• Media asset management & digital libraries for consistent item description, metadata binding and resource referencing.
• Streaming and delivery platforms that need structured descriptions of items and associated resources.
• Application developers & system architects implementing interoperable content workflows, metadata mapping, or ingestion/export pipelines.
• Archivists & preservation systems where explicit declaration of resources and fragments aids long-term management.

Keywords: media packaging, metadata interoperability, content delivery, digital asset management.

Related Standards

Part of the ISO/IEC 21000 (MPEG-21) series. Relevant companion parts include:

• Part 1 (Vision), Part 3 (Digital Item Identification), Part 5 (Rights Expression Language), Part 7 (Adaptation), Part 9 (File Format), Part 16 (Binary Format), plus others (Part 6, 8, 10, 11, 12, 15). Parts 4 and 14 noted as under preparation.

This standard is essential for implementing interoperable, XML-based multimedia item declarations within the MPEG-21 framework.