INTERNATIONAL ORGANISATION FOR STANDARDISATION
ORGANISATION INTERNATIONALE DE NORMALISATION
ISO/IEC JTC1/SC29/WG11
CODING OF MOVING PICTURES AND AUDIO
ISO/IEC JTC1/SC29/WG11 N11969
March 2011, Geneva, Switzerland
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Source |
Systems |
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Status |
Approved |
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Title |
Overview of MPEG-M Part 4 (Elementary Services) |
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Author |
Michael Grafl |
MPEG-M (ISO/IEC 23006) is a suite of standards that has been developed for the purpose of enabling the easy design and implementation of media-handling value chains whose devices interoperate because they are all based on the same set of technologies, especially technologies standardised by MPEG, exposed through standard APIs. Therefore, it is envisaged to accelerate the development of a broad market of products, content, services and applications designed to enrich one-way TV services with interoperable multichannel two-way content access and delivery.
The 2nd edition of this part of MPEG-M (ISO/IEC 23006-4) [1] specifies a set of Elementary Services and respective protocols enabling distributed applications to exchange information related to content items and parts thereof, including rights and protection information.
Together with the Aggregated Services defined in MPEG-M Part 5 [2], Elementary Services realize the concept of MPEG-M Services, which are an integral part of the MPEG-M architecture. An Elementary Service is understood as a Service of atomic nature, which cannot be usefully divided into smaller parts and does not normatively mandate other Services to be executed during its workflow.
The second edition conserves the architecture and design philosophy of the first edition, but stressing the Service Oriented Architecture character. Also, this second edition has been specified to address the demand of service specification for advanced IPTV terminals.
In the following, a short overview of Elementary Services specified in MPEG-M is presented and the concepts of Service Definition and Service Instance Declaration are introduced.
Each Elementary Service corresponds to an Operation and a type of Entity, on which the Operation is performed. Table 1 shows the Elementary Services defined in ISO/IEC 23006-4 2nd edition, with the rows indicating the Operations and the columns indicating the Entities.
Table 1: Elementary Services classified by Operations and Entities.
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Content |
Contract |
Device |
Event |
License |
Service |
User |
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Authenticate |
X |
X |
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|
|
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|
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Check With |
|
X |
|
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|
|
|
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Create |
X |
X |
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|
X |
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Deliver |
X |
X |
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|
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|
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Describe |
X |
|
X |
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X |
X |
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Identify |
X |
X |
X |
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|
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|
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Negotiate |
|
X |
|
|
X |
|
|
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Package |
X |
|
|
|
|
|
|
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Present |
|
X |
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|
|
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Process |
X |
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|
X |
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Request |
X |
X |
X |
X |
X |
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Revoke |
|
X |
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|
X |
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|
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Search |
X |
X |
X |
|
X |
X |
X |
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Store |
X |
X |
|
X |
X |
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Transact |
X |
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|
|
X |
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|
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Verify |
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X |
X |
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X |
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A Service Definition (also known as General Service Definition) consists of the specifications of protocols, interfaces, and respective data formats. The protocol data formats are XML-based messages. The workflow of a protocol is specified through a BPMN 2.0 [3] XML representation. The machine-readable representation of the Elementary Service workflows is further utilized in ISO/IEC 23006-5 for the aggregation of Services.
ISO/IEC 23006-4 2nd edition also specifies a mechanism for representing the instantiations of Services, called Service Instance Declaration. It enables a Service Provider to publish the connection end-point and configuration of a particular implementation of a Service.
[2] ISO/IEC 23006-5, Information Technology Multimedia Service Platform Technologies Part 5: Service Aggregation, Draft International Standard, Geneva, CH, March 2011.