ISO/IEC 21000-20:2013

Information technology — Multimedia framework (MPEG-21) — Part 20: Contract Expression Language

ISO/IEC 21000-20:2013 specifies a language for representing contracts in the Multimedia Framework formed for the transaction of MPEG-21 Digital Items or services related to the MPEG-21 Framework.

Technologies de l'information — Cadre multimédia (MPEG-21) — Partie 20: Langage d'expression des contrats

General Information

• Status: Withdrawn
• Publication Date: 11-Jul-2013
• Withdrawal Date: 11-Jul-2013
• ICS: 35.040 - Information coding
• ICS: 35.040.40 - Coding of audio, video, multimedia and hypermedia information
• Technical Committee: ISO/IEC JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information
• Drafting Committee: ISO/IEC JTC 1/SC 29 - Coding of audio, picture, multimedia and hypermedia information
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 15-Dec-2016

Relations

• Revised: ISO/IEC 21000-20:2016 - Information technology — Multimedia framework (MPEG-21) — Part 20: Contract Expression Language
• Effective Date: 05-Nov-2015

Standards Content (Sample)

INTERNATIONAL ISO/IEC
STANDARD 21000-20
First edition
2013-07-01


Information technology — Multimedia
framework (MPEG-21) —
Part 20:
Contract Expression Language
Technologies de l'information — Cadre multimédia (MPEG-21) —
Partie 20: Langage d'expression des contrats




Reference number
ISO/IEC 21000-20:2013(E)
©
ISO/IEC 2013

---------------------- Page: 1 ----------------------
ISO/IEC 21000-20:2013(E)

COPYRIGHT PROTECTED DOCUMENT


©  ISO/IEC 2013
All rights reserved. Unless otherwise specified, 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
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail [e-mail]
Web www.iso.org
Published in Switzerland

ii © ISO/IEC 2013 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/IEC 21000-20:2013(E)
Contents Page
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 . 2
4 Conventions . 2
4.1 Document conventions . 2
4.2 Namespace prefix conventions . 3
5 Relationship to other ISO/IEC 21000 parts . 4
6 Overview . 4
6.1 General aspects . 4
6.2 Syntactic representation . 5
7 Contract Structured Representation . 5
7.1 Introduction . 5
7.2 XML Schema definition . 5
7.3 CEL Deontic Structure . 15
7.4 CEL Extension for Exploitation of Intellectual Property Rights . 26
7.5 Examples . 36
7.6 CEL Extension mechanism (informative) . 40
Annex A (normative) Schemas . 41
A.1 CEL XML Schemas . 41
Annex B (informative) Examples of CEL Contracts . 42
B.1 Example 1 . 42
B.2 Example 2 . 47
Bibliography . 51


© ISO/IEC 2013 – All rights reserved                                                                                iii

---------------------- Page: 3 ----------------------
ISO/IEC 21000-20:2013(E)
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. In 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 2.
The main task of the joint technical committee is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO and IEC shall not be held responsible for identifying any or all such patent rights.
ISO/IEC 21000-20 was prepared by Joint Technical Committee ISO/IEC JTC 1, Information technology,
Subcommittee SC 29, Coding of audio, picture, multimedia and hypermedia information.
ISO/IEC 21000 consists of the following parts, under the general title Information technology — Multimedia
framework (MPEG-21):
 Part 1: Vision, Technologies and Strategy [Technical Report]
 Part 2: Digital Item Declaration
 Part 3: Digital Item Identification
 Part 4: Intellectual Property Management and Protection Components
 Part 5: Rights Expression Language
 Part 6: Rights Data Dictionary
 Part 7: Digital Item Adaptation
 Part 8: Reference software
 Part 9: File Format
 Part 10: Digital Item Processing
 Part 11: Evaluation Tools for Persistent Association Technologies [Technical Report]
 Part 12: Test Bed for MPEG-21 Resource Delivery [Technical Report]
 Part 14: Conformance Testing
 Part 15: Event Reporting
 Part 16: Binary Format
iv © ISO/IEC 2013 – All rights reserved

---------------------- Page: 4 ----------------------
ISO/IEC 21000-20:2013(E)
 Part 17: Fragment Identification of MPEG Resources
 Part 18: Digital Item Streaming
 Part 19: Media Value Chain Ontology
 Part 20: Contract Expression Language
 Part 21: Media Contract Ontology

© ISO/IEC 2013 – All rights reserved v

---------------------- Page: 5 ----------------------
ISO/IEC 21000-20:2013(E)
Introduction
Today, many elements exist to build an infrastructure for the delivery and consumption of multimedia content.
There was, however, no "big picture" to describe how these elements, either in existence or under
development, relate to each other. The aim for the ISO/IEC 21000 series has been to describe how these
various elements fit together. New standards as appropriate will be developed while other relevant standards
may be developed by other bodies.
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 ISO/IEC 21000 enabled open market. This will also be to the benefit of the
consumer providing them access to a large variety of content in an interoperable manner. The vision for
ISO/IEC 21000 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.
ISO/IEC 21000 aims thus at defining an open framework for multimedia applications, where users distribute,
consume, operate on and transact with content represented as Digital Items. These transactions can be
automatically governed by licenses using the Rights Expression Language from ISO/IEC 21000-5. However,
beyond the operative information present in a digital license, the digital representation of the complete
business agreements between the parties may prove useful for a number of purposes. The Contract
Expression Language is the ISO/IEC language for expressing such contracts in a structured representation.

vi © ISO/IEC 2013 – All rights reserved

---------------------- Page: 6 ----------------------
INTERNATIONAL STANDARD ISO/IEC 21000-20:2013(E)

Information technology — Multimedia framework (MPEG-21) —
Part 20:
Contract Expression Language
1 Scope
This part of ISO/IEC 21000 specifies a language for representing contracts in the Multimedia Framework
formed for the transaction of MPEG-21 Digital Items or services related to the MPEG-21 Framework.
The Contract Expression Language (CEL) aims at digitally representing the agreements made in an
environment of ISO/IEC 21000 use. These contracts include those about both transactions of content packed
as Digital Items as well as services provided around this content.
The range of contracts under scope are:
 contracts about transactions of content as MPEG-21 Digital Items;
 contracts about the provision of MPEG-21-based services, i.e. delivery, identification, encryption and
search.
The aspects represented by CEL contracts include:
 the textual clauses, in natural language as they are in the narrative contract, duly structured;
 the operative clauses, as computer language expressions.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 3166-1, Codes for the representation of names of countries and their subdivisions — Part 1: Country
codes
ISO 15836, Information and documentation — The Dublin Core metadata element set
ISO/IEC 21000-3, Information technology — Multimedia framework (MPEG-21) — Part 3: Digital Item
Identification
ISO/IEC 21000-5, Information technology — Multimedia framework (MPEG-21) — Part 5: Rights Expression
Language
ISO/IEC 21000-21, Information technology — Multimedia framework (MPEG-21) — Part 21: Media Contract
Ontology
XML Encryption Syntax and Processing Version 1.1, W3C Working Draft 16 March
2010,, http://www.w3.org/TR/xmlenc-core1/
IETF RFC 2141, Uniform Resource Name (URN) Syntax, May 1997, http://www.ietf.org/rfc/rfc2141.txt
IETF RFC 2396, Uniform Resource Identifiers (URI): Generic Syntax, Internet Standards Track Specification,
August 1998, http://www.ietf.org/rfc/rfc2396.txt
© ISO/IEC 2013 – All rights reserved 1

---------------------- Page: 7 ----------------------
ISO/IEC 21000-20:2013(E)
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1.1
MPEG-21 Contract
representation of agreements formed for the transaction of MPEG-21 Digital Items or services related to the
MPEG-21 Framework
3.1.2
MPEG-21 Service
system supplying utility in the Framework of MPEG-21
3.2 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.
CEL:  Contract Expression Language
IPRE:  Intellectual Property Rights Exploitation
MCO:  Media Contract Ontology
MPEG: Moving Picture Experts Group
MPEG-21: ISO/IEC 21000
MPEG-7: ISO/IEC 15938
OWL:  Web Ontology Language
RDF:  Resource Description Framework
REL:  Rights Expression Language
URI:  Uniform Resource Identifier (IETF Standard is RFC 3986)
URN:  Uniform Resource Name (IETF Standard is RFC 2141)
W3C:  World Wide Web Consortium
XML:  Extensible Markup Language (W3C Recommendation)
4 Conventions
4.1 Document conventions
4.1.1 XML Representation
The syntax of each XML element in the Contract Expression Language is specified using the constructs
provided by XML Schema [4]. XML Schema documents or its fragments are presented in orange boxes.
Omissions are marked with suspension points ([.]).


2 © ISO/IEC 2013 – All rights reserved

---------------------- Page: 8 ----------------------
ISO/IEC 21000-20:2013(E)
XML documents or its fragments are presented in gray boxes. Omissions are marked with suspension points
([…]).

This part of ISO/IEC 21000 also makes use of diagrams to express portions of XML Schema, as shown
in Figure 1.
Optional child
Sequence group
Required child
Parent element
Optional
unbounded
child
Required
unbounded
Choice group
child
Required child
with children

Figure 1 — Sample XML Schema diagram
This schema diagram states which elements are required (boxes with solid outline), those that are optional
(boxes with dashed outline), the number of occurrences of each element (0…), and the lineage between
elements (symbols between elements indicating either a choice, or a sequence).

Figure 2 — Compositors used in XML Schema diagrams
Compositors, as shown in Figure 2, describe (from left to right) respectively a sequence of elements, a choice
of elements and the all model.
4.2 Namespace prefix conventions
The namespace for CEL core XML Schema is:
urn:mpeg:mpeg21:cel:core:2012
The namespace for CEL extension on exploitation of intellectual property rights XML Schema is:
urn:mpeg:mpeg21:cel:ipre:2012
© ISO/IEC 2013 – All rights reserved 3

---------------------- Page: 9 ----------------------
ISO/IEC 21000-20:2013(E)
4.2.1 Use of prefixes
The CEL makes use of elements defined in other schemas, either given by MPEG-21 or others. The used
namespace prefixes together with their reference is given in Table 1.
Table 1 — Mapping of prefixes to namespaces in examples and text
Prefix Corresponding namespace Ref
cel-core urn:mpeg:mpeg21:cel:core:2012 Here
cel-ipre urn:mpeg:mpeg21:cel:ipre:2012 Here
dc http://purl.org/dc/elements/1.1/ ISO 15836
xsi http://www.w3.org/2001/XMLSchema-instance [4]
dsig http://www.w3.org/2000/09/xmldsig# [1]
rel-r urn:mpeg:mpeg21:2003:01-REL-R-NS ISO/IEC
21000-5
dii urn:mpeg:mpeg21:2002:01-DII-NS ISO/IEC
21000-3
xenc http://www.w3.org/2001/04/xmlenc# W3C XML
Encryption
Syntax and
Processing
xsd http://www.w3.org/2001/XMLSchema W3C XML
Schema
5 Relationship to other ISO/IEC 21000 parts
The Digital Item is the fundamental unit of distribution and transaction in the Multimedia Framework. While the
different parts of ISO/IEC 21000 deal with the components and different aspects of Digital Items, together they
form a complete integrated interoperable framework. This clause describes the relationship of this part of
ISO/IEC 21000 with the other parts of ISO/IEC 21000 in addressing the representation of the agreements for
the aforementioned transactions.
A contract represented following this part of ISO/IEC 21000 may become a part of a Digital Item (whose
declaration is given with ISO/IEC 21000-2). If so, it will be declared with the Type element of ISO/IEC 21000-
3 pointing to the CEL URI.
This part of ISO/IEC 21000 has the aim, as ISO/IEC 21000-21, of digitally representing contracts information.
CEL enables the structured representation of contracts‘ information making use of XML, while MCO provides
their semantic representation by means of OWL [2][5] or RDF [6]. Both parts share the goal of defining a
contract document able to provide the information listed in Clause 6.1.
This part of ISO/IEC 21000 makes use of the semantic for Actions, Facts and Services defined in
ISO/IEC 21000-21.
6 Overview
6.1 General aspects
A Contract Expression Language (CEL) contract is a document providing the following information, optional
unless otherwise stated:
 Identification of the contract itself – Required
 Possible relationships with other contracts
4 © ISO/IEC 2013 – All rights reserved

---------------------- Page: 10 ----------------------
ISO/IEC 21000-20:2013(E)
 The Parties
 The textual version of the contract
 A number of textual clauses which can be referenced by the operative part element
 The Object of the contract (Content or Service) - Required
 The Operative part, containing the contract information which have to be machine readable (deontic
expressions, links to textual clauses) – Required
CEL supports the possibility to encrypt either the whole contract or part of it.
CEL aims at providing the structural elements to syntactically represent operative clauses, in a machine-
readable form.
6.2 Syntactic representation
A Contract document defined by CEL shall be compliant to the XML representation defined in Clause 7. The
document format is specified by an XML Schema [4]. Any representation of a contract document defined by
CEL support the possibility to encrypt either the whole contract or part of it.
Contract documents shall validate against the CEL XML Schema, which is provided, as normative
specification, in Annex A. A detailed description of the structured representation is given in Clause 7.
7 Contract Structured Representation
7.1 Introduction
CEL standard specification enables the structured representation of digital media contracts by means of XML.
To this end, the CEL XML schema has been defined. It normatively defines the core elements for media
contracts. Its URI is:
urn:mpeg:mpeg21:cel:core:2012
Media contracts consist of deontic expressions which permit, obligate or prohibit users to execute generic
actions over digital media if the imposed conditions are fulfilled. Common actions and conditions in media
contracts have been defined as acts and constraints in the XML CEL extension on exploitation of intellectual
property rights. Its URI is:
urn:mpeg:mpeg21:cel:ipre:2012
MPEG-21 CEL contract documents shall validate against the XML Schema specification described in this
subclause.
7.2 XML Schema definition
7.2.1 Contract element and main structure
The root element of a CEL contract is the cel-core:contract element, which includes the structured
representation of the contract by means of deontic clauses, as well as the original text version of the contract.
It also provides mechanisms for relating the narrative clauses of the contract with its structured XML
representation.
The structure of the cel-core:contract element is depicted in Figure 3. It only has one attribute, the
contractId which uniquely identifies the contract.
© ISO/IEC 2013 – All rights reserved 5

---------------------- Page: 11 ----------------------
ISO/IEC 21000-20:2013(E)

Figure 3 — Root and main elements in the contract
The child elements of the cel-core:contract element are:
 optionally a choice of cel-core:textVersion containing the whole narrative contract as plain text; or
cel-core:encryptedTextVersion containing an encrypted version of the whole narrative contract
 cel-core:metadata, optionally including metadata such as contract author, contract language, etc.
 cel-core:contractsRelated, optionally including references to pre-existing contracts the validity of
which might be affected by the present one
 cel-core:party, the number of parties is open; 0 means that the contract is a template
 cel-core:body, exactly one body is mandatory, with the contract clauses
 cel-core:EncryptedContract, a full version of a contract encrypted
The CEL core XML Schema has the following header.
xmlns:cel-core="urn:mpeg:mpeg21:cel:core:2012"
xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"
xmlns:dii="urn:mpeg:mpeg21:2002:01-DII-NS"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
xmlns:rel-r="urn:mpeg:mpeg21:2003:01-REL-R-NS"
xmlns:dc="http://purl.org/dc/elements/1.1/"
targetNamespace="urn:mpeg:mpeg21:cel:core:2012"
elementFormDefault="qualified"
attributeFormDefault="unqualified">
schemaLocation="http://dublincore.org/schemas/xmls/qdc/2008/02/11/dc.xsd"/>
6 © ISO/IEC 2013 – All rights reserved

---------------------- Page: 12 ----------------------
ISO/IEC 21000-20:2013(E)
schemaLocation="http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-
21_schema_files/rel-r/rel-r.xsd"/>
schemaLocation="http://www.w3.org/TR/2002/REC-xmldsig-core-20020212/xmldsig-core-
schema.xsd"/>
schemaLocation="http://standards.iso.org/ittf/PubliclyAvailableStandards/MPEG-
21_schema_files/dii/dii.xsd"/>
schemaLocation="http://www.w3.org/TR/2002/REC-xmlenc-core-20021210/xenc-
schema.xsd"/>


7.2.1.1 Example
A sample contract may reference the XML Schema this way.

xmlns:dc="http://purl.org/dc/elements/1.1/"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:dsig="http://www.w3.org/2000/09/xmldsig#"
xmlns:dii="urn:mpeg:mpeg21:2002:01-DII-NS"
xmlns:xenc="http://www.w3.org/2001/04/xmlenc#"
xmlns:rel-r="urn:mpeg:mpeg21:2003:01-REL-R-NS"
xsi:schemaLocation="urn:mpeg:mpeg21:cel:core:2012 cel-core.xsd>

7.2.2 Metadata
Metadata can be added under the metadata element, giving information about the contract itself. Their
optional elements can be seen in Figure 4. A DublinCore placeholder is provided (element cel-
core:simpledc of type dc:elementContainer).

Figure 4 — Contract metadata elements
© ISO/IEC 2013 – All rights reserved 7

---------------------- Page: 13 ----------------------
ISO/IEC 21000-20:2013(E)
7.2.3 Element to relate contracts
The element cel-core:contractsRelated provides the means to relate the contract to other identified
contracts, between the same partners, as shown in Figure 5. The validity of the related contract can be
affected according to relationship type, which must be one of the following:
- supersedes, the referenced contract has to be considered terminated by the new agreement which
totally replaces it
- cancels, the parties agree to cancel all the effects of the referenced contract
- prevailsOver, the referenced contract is generally still valid, but in case of conflict the terms of the
new one prevail
- isAmendmentOf, the referenced contract is partially modified by the new agreement.

Figure 5 — contractsRelated element
7.2.4 The parties
The contract contains the parties in the contract, as described in Figure 6.
 cel-core:party, zero or more parties for which the contract is binding.
A contract template has zero parties, while a contract offer has one party.
Each party can be either a person (element cel-core:person) or an organization (element cel-core:
organization). In the latter case, for the party to be binding it is necessary that a signatory person is given
(element cel-core:signatory) together with his/her job title (element cel-core:jobTitle) within the
organization.
The cel-core:partyBasicGroup, common to both Person and Organization cases, and to the signatory
element as well, is made of:
 cel-core:name element, the name of the party
 a number of dc:identifier elements, to be used for giving references to registries in which the
party is registered, such as the VAT identification number
 the dc:description element, to provide a free description of the party
 the cel-core:details element, to provide further detailed information.
The party element might be further enriched with the address (element cel-core:address).
Without the dsig:Signature element the contract is not binding.
The attribute id, of type xsd:ID, is used for uniquely identify the party element within the contract
document.
8 © ISO/IEC 2013 – All rights reserved

---------------------- Page: 14 ----------------------
ISO/IEC 21000-20:2013(E)
The cel-core:PartyType complex type has been created with the structure depicted in Figure 6.

Figure 6 — Contract party element
The relevant elements of the XML Schema used for defining the cel-core:PartyType are given in the
following box.


 
 
 
 
 
 





 
 
 
 



© ISO/IEC 2013 – All rights reserved 9

---------------------- Page: 15 ----------------------
ISO/IEC 21000-20:2013(E)

 




 
 
 
  
  
  
  
 
 



7.2.4.1 Example
The following contract exemplifies two parties, without signatures. The first party is an organization,
represented by a signatory person who is further described by a virtual card [3]. Note the use of RDF [6], used
to give enriched information on the party. The second party is a person, whose details are given by means of
the MPEG7:Person element [7].

 
  RAI Radiotelevisione Italiana
  urn:VATIN:IT06382641006
  The Italian public broadcasting company
  
      Mario Rossi
       xmlns:rdf=”http://www.w3.org/1999/02/22-rdf-syntax-ns#”>
      
    [e-mail]
      
   
      
      CEO
    
 
  Viale Mazzini 14, 00195 Roma, ITALY



 
  John Doe
  urn:VATIN:123456
  Second party of the contract
   
    
     
         John
         Doe
         Dr
       
10 © ISO/IEC 2013 – All rights reserved

---------------------- Page: 16 ----------------------
ISO/IEC 21000-20:2013(E)
       
         John Doe Communications
       
        UK
       
         [phone]
       [e-mail]
       
    
   
 


7.2.5 Body element
The cel-core:body element contains the contr
...

INTERNATIONAL ISO/IEC
STANDARD 21000-20
First edition
2013-##-##

Information technology — Multimedia
framework (MPEG-21) —
Part 20:
Contract Expression Language
Technologies de l'information — Cadre multimédia (MPEG-21) —
Partie 20: Langage d'expression des contrats




Reference number
ISO/IEC 21000-20:2013(E)
©
ISO/IEC 2013

---------------------- Page: 1 ----------------------
ISO/IEC 21000-20:2013(E)


This CD-ROM contains:
1) the publication ISO/IEC 21000-20:2013 in portable document format (PDF), which can be viewed
using Adobe® Acrobat® Reader;
2) two .xsd files.
Adobe and Acrobat are trademarks of Adobe Systems Incorporated.


COPYRIGHT PROTECTED DOCUMENT


©  ISO/IEC 2013
All rights reserved. Unless otherwise specified, no part of this CD-ROM 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  Case postale 56  CH-1211 Geneva 20  Switzerland
Internet [e-mail]
Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
Published in Switzerland

ii © ISO/IEC 2013 – All rights reserved

---------------------- Page: 2 ----------------------
ISO/IEC 21000-20:2013(E)
Installation
If this publication has been packaged as a zipped file, do NOT open the file from the CD-ROM, but copy it to
the desired location in your local environment. Once the
...