信息技术.多媒体内容描述接口.第7部分:一致性测试

[中文适用范围]： 信息技术 多媒体内容描述接口 第7部分：一致性测试 [外文原描述]： ISO/IEC 15938-7:2003 specifies a metadata system for describing multimedia content. ISO/IEC 15938-7:2003 specifies how tests can be designed to verify whether descriptions and description consuming terminals meet the specifications of parts 1, 2, 3, 4 and 5 of ISO/IEC IEC 15938. In ISO/IEC 15938-7:2003, the creation or extraction of descriptions from multimedia content is not addressed specifically. A system producing descriptions may be said to be an ISO/IEC 15938 compatible description production system if it produces descriptions (binary or textual) that conform to the specifications of parts 1, 2, 3, 4 and 5 of ISO/IEC 15938. The characteristics of descriptions and the terminals consuming descriptions are defined for parts 1, 2, 3, 4 and 5 of ISO/IEC 15938 as follows. Descriptions: the characteristics of a specific description are defined according to syntax and semantics of elements from ISO/IEC 15938 (all parts) that are used in the description.Terminals: the characteristics of a terminal consuming a description are defined according to the required description decoding process for the elements used in the description. An example of a description decoding property is the arithmetic accuracy in which the value of element are represented. The capabilities of a description consuming terminal are determined by the domain of descriptions and elements that the terminal is capable of decoding. A description can be decoded by a terminal if the elements of the description are within the subset of ISO/IEC 15938 (all parts) specified for a given definition of decoder capabilities. Guidelines are given on constructing tests to verify conformance of descriptions and terminals. ISO/IEC 15938-7:2003 provides additional guidelines on how to construct test suites for checking conformance of terminals. In addition, some test descriptions are provided. The conformance testing consists of two stages: Systems testing and Description Definition Language (DDL) testing. The Systems conformance testing involves decoding the description stream, which may be in binary or textual access unit form, and checking that after the decoding of each access unit the current description tree maintained by the terminal is DDL conformant. In the case that the input description to the Systems processor is an XML file, the conformance is directly performed by the DDL testing. The DDL conformance testing involves parsing the textual XML description and checking that the description is well-formed and valid according to the schema comprised from parts 1, 2, 3, 4 and 5 of ISO/IEC 15938. The conformance testing of descriptions does not involve checking the semantics of the descriptions.