ISO/IEC 21000-3
(Main)Information technology — Multimedia framework (MPEG-21) — Part 3: Digital Item Identification
Information technology — Multimedia framework (MPEG-21) — Part 3: Digital Item Identification
ISO/IEC 21000 (MPEG-21) defines an open framework for multimedia delivery and consumption, with both the content creator and content consumer as focal points. The vision for MPEG-21 is to define a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by different communities. The basic architectural concept in MPEG-21 is the Digital Item. Digital Items are structured digital objects, including a standard representation and identification, and metadata. They are the basic unit of transaction in the MPEG-21 framework. Many MPEG-21 applications have the requirement to uniquely identify Digital Items. ISO/IEC 21000-3:2003 provides a simple but flexible mechanism to: Uniquely identify Digital Items and parts thereof (including resources); Uniquely identify IP related to the Digital Items (and parts thereof), for example abstractions; Uniquely identify Description Schemes; Use identifiers to link Digital Items with related information such as descriptive metadata (non-normative). The DII specification does not specify new identification systems for the content elements for which identification and description schemes already exist and are in use. Identifiers covered by this specification can be associated with Digital Items by including them in a specific place in the Digital Item Declaration (ISO/IEC 21000-2).
Technologies de l'information — Cadre multimédia (MPEG-21) — Partie 3: Identification des éléments numériques
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Second edition
Information technology —
Multimedia framework (MPEG-21) —
Part 3:
Digital Item Identification
Technologies de l'information — Cadre multimédia (MPEG-21) —
Partie 3: Identification des éléments numériques
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Reference number
© ISO/IEC 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
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© ISO/IEC 2025 – All rights reserved
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 1
3.1 Terms and definitions .1
3.2 Abbreviated terms .3
4 Identification of digital items and their parts. 4
4.1 Identifier element .4
4.1.1 Syntax . .4
4.1.2 Semantics .4
4.1.3 Notes .4
4.2 RelatedIdentifier element .5
4.2.1 Syntax . .5
4.2.2 Semantics .5
4.2.3 Example .5
4.3 Relationships element .5
4.3.1 Syntax . .6
4.3.2 Semantics .6
4.3.3 MPEG-21 core ontology for DI relationships .6
4.4 Type element .7
4.4.1 Syntax . .7
4.4.2 Semantics .7
4.4.3 Example .7
4.5 Digital Item identification XML schema definition .7
4.6 Examples .8
4.6.1 Example: Identification of a music release .9
4.6.2 Example: Referring to Digital Item in external DID document .9
4.6.3 Example: Referring to resources stored on external server .11
4.6.4 Example: Identifying a sound recording and the related underlying musical work .11
4.6.5 Example: Identifying a Digital Item type .11
5 Identification of description schemes .12
Annex A (informative) Interoperability considerations on resolution systems .13
Annex B (informative) List of existing identification and description schemes . 17
Annex C (informative) Usage of this document in the MPEG-21 multimedia framework .25
Annex D (informative) Relationships element employment example .28
Bibliography .34
PROOF/ÉPREUVE
© ISO/IEC 2025 – All rights reserved
iii
Foreword
ISO (the 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 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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of document should be noted. This document was drafted in accordance with the editorial rules of the ISO/
IEC Directives, Part 2 (see www.iso.org/directives or www.iec.ch/members_experts/refdocs).
ISO and IEC draw attention to the possibility that the implementation of this document may involve the
use of (a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any
claimed patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had
received notice of (a) patent(s) which may be required to implement this document. However, implementers
are cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents and https://patents.iec.ch. ISO and IEC shall not be held
responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www.iso.org/iso/foreword.html.
In the IEC, see www.iec.ch/understanding-standards.
This document was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
This second edition cancels and replaces the first edition (ISO/IEC 21000-3:2003), which has been technically
revised. It also incorporates ISO/IEC 21000-3:2003/Amd 1:2007 and ISO/IEC 21000-3:2003/Amd 2:2013.
The main changes are as follows:
— removal of Annex A (normative) - Requirements for the Registration Authority for Digital Item
Identification Systems, and related descriptions that requires ISO/IEC 21000-3 to employ Registration
Authority.
— updating information on ISO 15706-2 (ISAN), which has recently been approved as an International
Standard.
— provision of MPEG-21 DII with the ability to explicitly and unambiguously describe existing relationships
between different MPEG-21 Digital Items. It also conveys the base inter-DI relationship taxonomy in the
form of an RDF/OWL ontology.
A list of all parts in the ISO/IEC 21000 series can be found on the ISO and IEC websites.
Any feedback or questions on this document should be directed to the user’s national standards
body. A complete listing of these bodies can be found at www.iso.org/members.html and
www.iec.ch/national-committees.
PROOF/ÉPREUVE
© ISO/IEC 2025 – All rights reserved
iv
Introduction
0.1 Executive summary for MPEG-21
Today, many elements exist to build an infrastructure for the delivery and consumption of multimedia
content. The aim for MPEG-21 multimedia framework (ISO/IEC 21000) is to describe how these various
elements fit together.
The result is an open framework for multimedia delivery and consumption, with both the content creator
and content consumer as focal points. This open framework provides content creators and service providers
with equal opportunities in the MPEG-21 enabled open market. This will also be to the benefit of the content
consumer providing them access to a large variety of content in an interoperable manner.
The vision for MPEG-21 is to define a multimedia framework to enable transparent and augmented use of
multimedia resources across a wide range of networks and devices used by different communities.
This document specifies how Digital Items (see ISO/IEC 21000-2) and parts and collections thereof can be
uniquely identified.
0.2 Organisation of the document
This introduction contains an overview of MPEG-21 Digital Items and the relation between ISO/IEC 21000-2
and this document.
Clause 4 specifies how to uniquely identify Digital Items, how to associate related identifiers with Digital
Items and how to identify different types of Digital Items. Clause 5 then specifies how to associate metadata
with Digital Items by using description scheme identifiers.
Annex A contains an example of how to resolve a unique identifier to appropriate metadata. Annex B contains
a list of existing identification schemes that can be used by this document. Annex C provides an approach to
dealing with varying functional granularities for identifying Digital Items. Annex D provides an example of
how to express the relationship between two Digital Items.
0.3 Introduction to Digital Items
Within any system (such as MPEG-21) that proposes to facilitate a wide range of actions involving Digital
Items, there is a need for a very precise description for defining exactly what constitutes such an “item”.
Clearly there are many kinds of content, and probably just as many possible ways of describing it to reflect
its context of use. This presents a strong challenge to lay out a powerful and flexible model for Digital Items
which can accommodate the myriad forms that content can take (and the new forms it will assume in the
future). Such a model is only truly useful if it yields a format that can be used to represent any Digital Items
defined within the model unambiguously and communicate them, and information about them, successfully.
ISO/IEC 21000-2 provides such flexibility for representing Digital Items.
0.4 Example of a Digital Item
This subclause provides a simple example of a Digital Item. More complex examples can be fou
...
INTERNATIONAL ISO/IEC
STANDARD 21000-3
Second edition
2023-10-20
Information technology — Multimedia
framework (MPEG-21) —Part 3:Digital
Item Identification
Technologies de l'information — Cadre multimédia (MPEG-21) —
Partie 3: Identification des éléments digitaux
Reference number
ISO/IEC PRF 21000-3
ISO/IEC JTC 1/SC 29
Secretariat: JISC
Date: 2025-03-10
Information technology — Multimedia framework (MPEG-21) —
Part 3:
Digital Item Identification
Technologies de l'information — Cadre multimédia (MPEG-21) —
Partie 3: Identification des éléments numériques
PROOF
Reference number
ISO/IEC DIS 21000-3 (E)ISO/IEC PRF 21000-3:2025(en)
© ISO/IEC 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
at the address below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: + 41 22 749 01 11
E-mail: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO/IEC 2023 — All rights reserved
iii
© ISO/IEC 2025 – All rights reserved
iii
Contents Page
Foreword . vi
Introduction . viii
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
4 Identification of digital items and their parts . 6
5 Identification of description schemes . 20
Annex A (informative) Interoperability considerations on resolution systems . 21
Annex B (informative) List of existing identification and description schemes . 26
Annex C (informative) Usage of this document in the MPEG-21 multimedia framework . 36
Annex D (informative) Relationships element employment example . 41
Bibliography . 55
Foreword iv
Introduction vi
1 Scope . 1
2 Normative references . 1
3 Terms, definitions and abbreviated terms . 2
3.1 Terms and definitions . 2
3.2 Abbreviated terms . 4
4 Identification of digital items and their parts . 5
4.1 Identifier element. 5
4.1.1 Syntax . 5
4.1.2 Semantics . 5
4.1.3 Notes (informative) . 5
4.2 RelatedIdentifier element . 5
4.2.1 Syntax . 6
4.2.2 Semantics . 6
4.2.3 Example . 6
4.3 Relationships element . 6
4.3.1 Syntax . 6
4.3.2 Semantics . 7
4.3.3 MPEG-21 core ontology for DI relationships . 7
4.4 Type element . 8
4.4.1 Syntax . 8
4.4.2 Semantics . 8
4.4.3 Example . 8
4.5 Digital Item identification XML schema definition . 8
4.6 Examples (informative) . 9
© ISO/IEC 2023 — All rights reserved
iv
© ISO/IEC 2025 – All rights reserved
iv
ISO/IEC DIS 21000-3 (E)ISO/IEC PRF 21000-3:2025(en)
4.6.1 Example: Identification of a music release . 9
4.6.2 Example: Referring to Digital Item in external DID document . 9
4.6.3 Example: Referring to resources stored on external server . 11
4.6.4 Example: Identifying a sound recording and the related underlying musical work . 11
4.6.5 Example: Identifying a Digital Item type . 12
5 Identification of description schemes . 12
Annex A (informative) Interoperability considerations on resolution systems . 13
A.1 General . 13
A.2 Necessary functions and resolution system switcher . 13
A.3 An overall example of a DID browsing system with resolution system switcher . 15
A.4 Summary . 15
Annex B (informative) List of existing identification and description schemes . 16
B.1 General . 16
B.2 Common Information System – CIS . 16
B.3 Content ID Forum – cIDf . 16
B.4 Digital Object Identifier – DOI . 17
B.5 Dublin Core Metadata Initiative – DCMI . 18
B.6 The EAN/UCC System . 18
B.7 Global Release Identifier – GRID . 18
B.8 Identifier for Versions of Audiovisual works – V-ISAN . 18
B.9 International Standard Audiovisual Number – ISAN . 19
B.10 International Standard Book Number – ISBN . 19
B.11 International Standard Recording Code – ISRC . 20
B.12 International Standard Serial Number – ISSN . 20
B.13 International Standard Textual Work Code – ISTC . 21
B.14 International Standard Work Code – ISWC . 21
B.15 INteroperability of Data in E-Commerce Systems – INDECS . 21
B.16 ONline Information eXchange – ONIX International . 22
B.17 URL-based Identification Schemes . 23
Annex C (informative) Usage of this specification in the MPEG-21 multimedia framework . 24
C.1 Overview . 24
C.2 Expressing varying functional granularity. 25
C.3 Relationship types . 26
Annex D (informative) Relationships element employment example . 27
D.1 Overview . 27
D.2 Sample extending ontology . 27
D.3 Inter-DI relationship declaration example . 30
Annex E (informative) Patent statements . 32
Bibliography 33
© ISO/IEC 2023 — All rights reserved
v
© ISO/IEC 2025 – All rights reserved
v
Foreword
ISO (the 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
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.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
document should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC
Directives, Part 2 (see www.iso.org/directiveswww.iso.org/directives or
www.iec.ch/members_experts/refdocs).
Field Code Changed
ISO and IEC draw attention to the possibility that the implementation of this document may involve the use of
(a) patent(s). ISO and IEC take no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO and IEC had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent database
available at www.iso.org/patents and https://patents.iec.ch.www.iso.org/patents and https://patents.iec.ch.
ISO and IEC shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
relat
...
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