1、INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.170 (02/98) SERIES T: TERMINALS FOR TELEMATIC SERVICES Framework of the T.170-Series of Recommendations ITU-T Recommendation T. 170 (Previously CCITT Recommendation) STD-ITU-T RECMN T.170-ENGL 1778 48b2591
2、Ob45382 389 = ITU-T RECOMMENDATION T.170 FRAMEWORK OF THE T.170-SERIES OF RECOMMENDATIONS Summary This Recommendation gives an overview of the T. 170-Series of Recommendations and specifies the framework in which they can be used. Source ITU-T Recommendation T.170 was prepared by ITU-T Study Group 1
3、6 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 6th of February 1998. STD-ITU-T RECMN T.170-ENGL 1998 4862593 Ob45384 157 FOREWORD IIZT (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunications. The ITU Telecom
4、munication Standardization Sector (ITU-T) is a permanent organ of the ITU. The ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardiza
5、tion Conference (WTSC), which meets every four years, establishes the topics for study by the ITU-T Study Groups which, in their turn, produce Recommendations on these topics. The approval of Recommendations by the Members of the ITU-T is covered by the procedure laid down in WTSC Resolution No. 1.
6、In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with IS0 and IEC. NOTE In this Recommendation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a rec
7、ognized operating agency. INTELLECTUAL PROPERTY RIGHTS The ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. The ITU takes no position concerning the evidence, validity or applicability of c
8、laimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, the ITU had not received notice of intellectual property, protected by patents, which may be required to implement this
9、 Recommendation. However, implementors are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. O ITLJ 1998 All rights reserved. No part of this publication may be reproduced or utilized in any form or by any means, electro
10、nic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation T.170 (02/98) 1 STD.ITU-T RECMN TmL70-ENGL 1998 48b259L Ob45385 O93 CONTENTS 3 3.1 3.2 4 4.1 4.2 4.3 4.4 4.5 4.6 5 Scope Normative references Definitions and abbreviations . Definit
11、ions Abbreviations . Overview Recommendation T . 17 1 i Recommendation T . 172 2 Recommendation T . 173 3 Recommendation T . 174 4 Recommendation T . 175 5 Recommendation T . 176 6 Example of a multifunctional terminal . Recommendation T.170 (02/98) Page 1 1 1 1 1 2 3 3 3 3 3 3 4 . 111 STDSITU-T REC
12、MN TmL70-ENGL 1998 D 4862591 0645386 T2T Recommendation T.170 FRAMEWORK OF THE T.170-SERIES OF RECOMMENDATIONS (Geneva, 1998) 1 Scope This Recommendation gives an overview of the T. 170-Series of Recommendations and specifies the fiamework in which they can be used. 2 Normative references The follow
13、ing ITU-T Recommendations and other references contain provisions which, through reference in this text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; all users of this Re
14、commendation are therefore encouraged to investigate the possibility of applying the most recent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. i ITU-T Recommendation T. 171 (1 996), Protocols for interact
15、ive audiovisual services: Coded representation of multimedia and hypermedia. 2 ITU-T Recommendation T. 172 (1 998), MHEG-5 support for base-level interactive applications. ITU-T Recommendation T. 173 (1 997), MHEG-3 script interchange representation. ITU-T Recommendation T. 174 (1 996), Application
16、Programming Interface (APO for ITU-T Recommendation T. 175 (1 998), Application Programming Interface (APO for ITU-T Recommendation T.176 (1998), API for Digital Storage Media Command and Control (DSM-CC). 3 4 MHEG-I. 5 6 MHEG-5. 3 Definitions and abbreviations 3.1 Definitions This Recommendation de
17、fines the following term: Application Programming Interface (API): A boundary across which a sofhvare application uses facilities of programming languages to invoke software services. These facilities may include procedures or operations, shared data objects and resolution of identifiers. 3.2 Abbrev
18、iations This Recommendation uses the following abbreviations: API Application Programming Interface ASN. 1 Abstract Syntax Notation One ATM Asynchronous Transfer Mode Recommendation T.170 (02/98) 1 STD-ITU-T RECMN T.17D-ENGL 1998 48b2591 Ob45387 9bb DAVIC DSM-CC DSM-CC UN DSM-CC UU IIOP MHEG OMG ORB
19、 STU UNO VM Digital Audio Visual Council Digital Storage Media Command and Control DSM-CC User to Network DSM-CC User to User Internet Inter ORB Protocol Multimedia and Hypermedia information coding Experts Group Object Management Group Object Request Broker Set Top Unit Universal Networked Objects
20、Virtual Machine 4 Overview Figure 1 shows the framework of the T. 170-Series of Recommendations: Framework Rec. T. 170 MHEG-1 Rec. T.171 MHEG-5 Rec. T. 172 Virtual Machine (VM) Rec. T. 173 MHEG-5API / Rec. T. 175 ISO/IEC DIS 13818-6 DSM-CC T1601910-97 Figure 1rn.170 - Framework The T. 170-Series of
21、Recommendations provides Standards defining the syntax of Multimedia and Hypermedia Applications as well as it provides a Virtual Machine and a set of APIS in order to be able to build a software architecture for multimedia applications that guarantees application portability. 2 Recommendation T.170
22、 (02/98) STDmITU-T RECMN T-170-ENGL 1998 m 48b259L Ob45388 8T2 m Applications can consist of either MHEG-1 or MHEG-5 objects. Both applications, MHEG-1 or MHEG-5 can use Virtual Machine (VM) code to enhance their functionality. However, application portability is guaranteed because the necessary int
23、erfaces for the terminal architecture are fully specified. Recommendation T. 1 7 1 and Recommendation T. 173 are generic standards covering the entire domain of possible multimedia applications. Recommendation T.172 and the DAVIC Virtual Machine can be viewed as specialisation of the above-mentioned
24、 Recommendations and are hence more suitable to be implemented in a concrete information retrieval scenario. A typical device based on the software architecture introduced in Figure 1 would be a Set Top Unit (STU) compliant with DAVIC 1.2 specifications. An Implementers Handbook for the T.170-Series
25、 is also available which gives guidance on how to implement Recommendation T. 172 and DSM-CC. The following subclauses introduce the scope of the respective Recommendations. 4.1 Recommendation T.171 i Recommendation T. 171 specifies the coded representation of multimedia application in the ASN. 1 fo
26、rmat. MHEG-1 is a generic standard applicable to a broad range of applications that can serve for hture profiling activities. 4.2 Recommendation T.172 2 Recommendation T. 172 specifies semantics and final-form interchange syntax for MHEG-5 objects, based on concepts defined in Recommendation T.171.
27、These objects are intended for use in the domain of simple clientlserver interactive multimedia applications, e.g. (Near) Video on Demand applications, navigation and browsing applications. 4.3 Recommendation T.173 3 Recommendation T. 173 specifies the MHEG Script Interchange Representation (MHEG-SI
28、R) for the contents of script objects, i.e. the encoding of the script data component of the MHEG script class. The script functionality specified in Recommendation T. 173 is based on VM-technology. 4.4 Recommendation T.174 141 Recommendation T. 174 specifies the API for the manipulation of multimed
29、ia and hypermedia information objects, i.e. the API that shall be provided by MHEG-1 engines for their control by applications. 4.5 Recommendation T.175 5 Recommendation T.175 specifies the API for the manipulation of multimedia and hypermedia information objects, i.e. the API that shall be provided
30、 by MHEG-5 engines for their control by applications running on a DAVIC 1.1 compliant terminal. 4.6 Recommendation T.176 6 Recommendation T. 176 specifies the API of DSM-CC for the use in basic multimedia applications. Recommendation T. 176 is applicable to DAVIC compliant systems. Recornmendation T
31、.170 (02/98) 3 - - STDmITU-T RECMN T-170-ENGL 1798 4862591 Ob45389 737 5 Figure 2 gives an example of the protocol stacks used in a multifunctional terminal supporting retrieval, conversational and conferencing services. Example of a multifunctional terminal 4 Cai1 control Q.293 1 System Control H.2
32、45 - Object data coding T. 170 IIOP TCP Audio Coding G.711/ WEG-1 H.262 Data coding 1 T.120 (conferencing case) Real-Time Graphics etc. DVB-SI Multimedia multiplex and synchronisation H.222.1bI.222.0 I I Network Adaptation AAL 5 (1.363.5) I ATM I I T1601920-97 Figure 2m.170 - Example of a multifunct
33、ional terminal Recommendation T.170 (02/98) _ STD-ITU-T RECMN T.170-ENGL 1998 m 4862591 0645390 450 H Series A Series B Series C Series D Series E Series F Series G Series H Series I Series J Series K Series L Series M Series N Series O Series P Series Q Series R Series S Series T Series U Series V
34、Series X Series Y Series Z ITU-T RECOMMENDATIONS SERIES Organization of the work of the ITU-T Means of expression: definitions, symbols, classification General telecommunication statistics General tariff principles Overall network operation, telephone service, service operation and human factors Non
35、-telephone telecommunication services Transmission systems and media, digital systems and networks Audiovisual and multimedia systems Integrated services digital network Transmission of television, sound programme and other multimedia signals Protection against interference Construction, installatio
36、n and protection of cables and other elements of outside plant TMN and network maintenance: international transmission systems, telephone circuits, telegraphy, facsimile and leased circuits Maintenance: international sound programme and television transmission circuits Specifications of measuring eq
37、uipment Telephone transmission quality, telephone installations, local line networks Switching and signalling Telegraph transmission Telegraph services terminal equipment Terminals for telematic services Telegraph switching Data communication over the telephone network Data networks and open system communications Global information infrastructure Programming languages Printed in Switzerland Geneva, 1998
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