ISO/IEC 15938-5:2003 specifies a metadata system for describing multimedia content. ISO/IEC 15938-5:2003 specifies the Multimedia Description Schemes (MDS) description tools (Description Schemes, Descriptors, and datatypes) that comprise ISO/IEC 15938-5:2003 by specifying the normative syntax of each description tool using Description Definition Language (DDL) (see ISO/IEC 15938-2) and the normative semantics including semantics of each component of each description tool (attributes and elements). ISO/IEC 15938-5:2003 also provides informative examples that illustrate the instantiation of description tools in creating descriptions conforming to ISO/IEC 15938-5:2003.
ISO/IEC 15938-5:2003 defines the following basic elements: schema tools (the root element, top-level types, description metadata, and packages), basic datatypes (integers, reals, vectors, matrices), linking and media localization tools (spatial and temporal localization), basic description tools (language, text, classification schemes). ISO/IEC 15938-5:2003 defines the following content description tools, which describe the features of the multimedia content and the immutable metadata related to the multimedia content: structure description tools (spatio-temporal segments of multimedia content) and semantic description tools ("real-world" semantics related to or captured by the multimedia content, including objects, events, concepts, and so forth). ISO/IEC 15938-5:2003 defines additionally the following description tools for content metadata: media description (storage format, encoding), creation and production (title, creator, classification, purpose), and usage (access rights, publication). The content description and metadata tools are related in the sense that the content description tools use the content metadata tools. For example, a description of creation and production or media information can be attached to an individual video or video segment in order to describe the structure and creation and production of the multimedia content. ISO/IEC 15938-5:2003 also defines description tools for navigation and access (browsing, summarization), content organization (collections and models), and user interaction (user preferences pertaining to consumption of multimedia and usage history). Finally, ISO/IEC 15938-5:2003 defines classification schemes, which organize terms that are used by the description tools.