1、 Reference numberISO/IEC 15938-2:2002(E)ISO/IEC 2002INTERNATIONAL STANDARD ISO/IEC15938-2First edition2002-04-01Information technology Multimedia content description interface Part 2: Description definition language Technologies de linformation Interface de description du contenu multimdia Partie 2:
2、 Langage de dfinition de description (DDL) Adopted by INCITS (InterNational Committee for Information Technology Standards) as an American National Standard.Date of ANSI Approval: 10/17/2002Published by American National Standards Institute,25 West 43rd Street, New York, New York 10036Copyright 2002
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8、l Secretariat at the address given below. ISO/IEC 2002 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO
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10、IEC 2002 All rights reserved iiiContents Page Foreword.iv Introduction.v 1 Scope 1 1.1 Scope of this International Standard.1 1.2 Overview of Description Definition Language1 1.3 Structure of this document.2 2 Normative references2 3 Terms and definitions .4 3.1 Conventions .4 3.2 Wrapper of the sch
11、ema.5 3.3 Terminology .5 4 Symbols and abbreviated terms 7 5 MPEG-7-specific Extensions 8 5.1 MPEG-7 Structural Extensions.8 5.2 MPEG-7 Datatype Extensions 11 6 Unused XML Schema Features 14 Annex A (informative) Overview of XML Schema Structural Components.15 A.1 Introduction15 A.2 Detailed Descrip
12、tion15 Annex B (informative) Overview of XML Schema Datatypes29 B.1 Introduction29 B.2 Detailed Description29 Annex C (normative) XML Schema for MPEG-7 Extensions 34 Annex D (informative) Patent statements .35 Bibliography37 ISO/IEC 15938-2:2002(E) iv ISO/IEC 2002 All rights reserved Foreword ISO (t
13、he International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC participate in the development of International Standards through technical committees
14、established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, governmental and non-governmental, in liaison with ISO and IEC, also take part in the work. I
15、n the field of information technology, ISO and IEC have established a joint technical committee, ISO/IEC JTC 1. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of the joint technical committee is to prepare International Standar
16、ds. Draft International Standards adopted by the joint technical committee are circulated to national bodies for voting. Publication as an International Standard requires approval by at least 75 % of the national bodies casting a vote. ISO/IEC 15938-2 was prepared by Joint Technical Committee ISO/IE
17、C JTC 1, Information technology, Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information. ISO/IEC 15938 consists of the following parts, under the general title Information technology Multimedia content description interface: Part 1: Systems Part 2: Description definition
18、 language Part 3: Visual Part 4: Audio Part 5: Multimedia description schemes Part 6: Reference software Part 7: Conformance testing Part 8: Extraction and use of MPEG-7 descriptions Annex C forms a normative part of this part of ISO/IEC 15938. Annexes A, B and D are for information only. ISO/IEC 15
19、938-2:2002(E) ISO/IEC 2002 All rights reserved vIntroduction This standard, also known as “Multimedia Content Description Interface“, provides a standardized set of technologies for describing multimedia content. The standard addresses a broad spectrum of multimedia applications and requirements by
20、providing a metadata system for describing the features of multimedia content. The following are specified in this standard: Description Schemes (DS) describe entities or relationships pertaining to multimedia content. Description Schemes specify the structure and semantics of their components, whic
21、h may be Description Schemes, Descriptors, or datatypes. Descriptors (D) describe features, attributes, or groups of attributes of multimedia content. Datatypes are the basic reusable datatypes employed by Description Schemes and Descriptors. Description Definition Language (DDL) defines Description
22、 Schemes, Descriptors, and Datatypes by specifying their syntax, and allows their extension. Systems tools support delivery of descriptions, multiplexing of descriptions with multimedia content, synchronization, file format, and so forth. This standard is subdivided into eight parts: Part 1 Systems:
23、 specifies the tools for preparing descriptions for efficient transport and storage, compressing descriptions, and allowing synchronization between content and descriptions. Part 2 Description definition language: specifies the language for defining the standard set of description tools (DSs, Ds, an
24、d datatypes) and for defining new description tools. Part 3 Visual: specifies the description tools pertaining to visual content. Part 4 Audio: specifies the description tools pertaining to audio content. Part 5 Multimedia description schemes: specifies the generic description tools pertaining to mu
25、ltimedia including audio and visual content. Part 6 Reference software: provides a software implementation of the standard. Part 7 Conformance testing: specifies the guidelines and procedures for testing conformance of implementations of the standard. Part 8 Extraction and use of MPEG-7 descriptions
26、: provides guidelines and examples of the extraction and use of descriptions. This document specifies the Description Definition Language (DDL) part of the ISO/IEC 15938 standard. The DDL is the language (and syntax) for constraining the structure and content of MPEG-7 descriptions. This document al
27、so provides informative examples demonstrating the use of the DDL to constrain and instantiate MPEG-7 descriptions. INTERNATIONAL STANDARD ISO/IEC 15938-2:2002(E) ISO/IEC 2002 All rights reserved 1Information technology Multimedia content description interface Part 2: Description definition language
28、 1 Scope 1.1 Scope of this International Standard This International Standard specifies a metadata system for describing multimedia content. It specifies the Description Definition Language (DDL) that comprises part 2 of the standard (ISO/IEC 15938-2). The goal of this part of the MPEG-7 Internation
29、al Standard is to specify a language that will enable MPEG-7 users and developers to: create valid MPEG-7 description schemes and descriptors; develop tools such as editors and parsers for processing descriptions, description schemes and descriptors; generate refinements, extensions and modification
30、s to the DDL. This International Standard describes the features of the DDL. It defines the syntax of the DDL constructs and datatypes and provides optional (informative) examples that illustrate the application of the DDL to the specification and instantiation of MPEG-7 descriptions. 1.2 Overview o
31、f Description Definition Language This International Standard, known as the “Multimedia Content Description Interface“, aims at providing standardized core technologies allowing the description of audiovisual data content in multimedia environments. This is a challenging task given the broad spectru
32、m of requirements and targeted multimedia applications, and the broad number of audiovisual features of importance in such a context. In order to achieve this broad goal, the standard specifies: - Descriptors (D): representations of Features, that define the syntax and the semantics of each feature
33、representation; - Description Schemes (DS), that specify the structure and semantics of the relationships between their components, which may be both Ds and DSs; - A Description Definition Language (DDL), to allow the creation of new DSs and, possibly, Ds and to allow the extension and modification
34、of existing DSs; - System tools, to support multiplexing of description, synchronization issues, transmission mechanisms, file format, etc. The DDL forms a core part of the MPEG-7 standard. It provides the solid descriptive foundation through which users can create their own Description Schemes and
35、Descriptors. The DDL defines the syntactic rules to express and combine Description Schemes and Descriptors. According to the definition in the MPEG-7 Requirements Document 1 the DDL is .a language that allows the creation of new Description Schemes and, possibly, Descriptors. It also allows the ext
36、ension and modification of existing Description Schemes. ISO/IEC 15938-2:2002(E) 2 ISO/IEC 2002 All rights reserved The DDL is not a modelling language such as Unified Modelling Language (UML) but a schema language to represent the results of modelling audiovisual data, i.e., DSs and Ds. The DDL mus
37、t satisfy the MPEG-7 DDL requirements. It has to be able to express spatial, temporal, structural, and conceptual relationships between the elements of a DS, and between DSs. It must provide a rich model for links and references between one or more descriptions and the data that it describes. In add
38、ition, it must be platform and application independent and human- and machine-readable. (Non-normative) DDL Parser applications will be required which are capable of validating description schemes (content and structure) and descriptor data types both primitive (integer, text, date, time) and compos
39、ite (histograms, enumerated types), against the DDL. The DDL Parsers must also be capable of validating MPEG-7 descriptions or instantiations, against their corresponding validated MPEG-7 schemas (DSs and Ds). The DDL design has been informed by numerous proposals and input documents submitted to MP
40、EG-7 since the MPEG-7 Call for Proposals in October 1998 2. It has also been heavily influenced by W3Cs XML Schema Language 3,4,5 and the Resource Description Framework (RDF) 6. At the 51stMPEG meeting in Noordwijkerhout in March 2000, it was decided to adopt XML Schema Language 3,4, 5 as the MPEG-7
41、 DDL. However because XML Schema language was not designed specifically for audiovisual content, certain extensions have been necessary in order to satisfy all of the MPEG-7 DDL requirements. Hence the W3Cs XML Schema Language Recommendations 3,4,5 together with the MPEG-7 extensions described in th
42、is document, constitute the normative reference for the MPEG-7 DDL. Overviews of the XML Schema Language structural components and datatypes are given in Annexes A and B for informative purposes only. If Annexes A and B contradict the normative references 3,4,5 then the normative references should b
43、e used as the definitive specification. 1.3 Structure of this document The DDL can be broken down into the following logical normative components: - The XML Schema structural language components; - The XML Schema datatype language components; - The MPEG-7 specific extensions. The complete normative
44、specifications for XML Schema structural and datatype components can be found in 4 and 5 respectively. This International Standard provides the normative specification of the MPEG-7-specific extensions as well as non-normative examples which provide the MPEG-7 community with a clear understanding of
45、 the DDL and assist with the development of valid description schemes and descriptors. The structure of the remainder of this International Standard is as follows: Clause 5 describes the normative MPEG-7specific extensions. Clause 6 describes those features of XML Schema which are currently not used
46、 by MPEG-7. Annex A provides an informative overview of the structural components of XML Schema Language. Annex B provides an informative overview of the datatyping mechanisms within XML Schema Language. Annex C provides the normative XML Schema which defines the MPEG-7 extensions. Annex D contains
47、the Patent Statements. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO/IEC 15938. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. Howe
48、ver, parties to agreements based on this part of ISO/IEC 15938 are encouraged to ISO/IEC 15938-2:2002(E) ISO/IEC 2002 All rights reserved 3investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the no
49、rmative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. The Telecommunication Standardization Bureau maintains a list of currently valid ITU-T Recommendations. ISO 8601, Data elements and interchange formats Information interchange Representation of dates and times ISO 639 (all parts), Codes for the representation of names of languages ISO 3166-1, Codes for the representation of n
