1、 International Telecommunication Union ITU-T F.741TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (09/2005) SERIES F: NON-TELEPHONE TELECOMMUNICATION SERVICES Audiovisual services Service description and requirements for audiovisual on-demand services ITU-T Recommendation F.741 ITU-T F-SERIES RECOMM
2、ENDATIONS NON-TELEPHONE TELECOMMUNICATION SERVICES TELEGRAPH SERVICE Operating methods for the international public telegram service F.1F.19 The gentex network F.20F.29 Message switching F.30F.39 The international telemessage service F.40F.58 The international telex service F.59F.89 Statistics and p
3、ublications on international telegraph services F.90F.99 Scheduled and leased communication services F.100F.104 Phototelegraph service F.105F.109 MOBILE SERVICE Mobile services and multidestination satellite services F.110F.159 TELEMATIC SERVICES Public facsimile service F.160F.199 Teletex service F
4、.200F.299 Videotex service F.300F.349 General provisions for telematic services F.350F.399 MESSAGE HANDLING SERVICES F.400F.499DIRECTORY SERVICES F.500F.549 DOCUMENT COMMUNICATION Document communication F.550F.579 Programming communication interfaces F.580F.599 DATA TRANSMISSION SERVICES F.600F.699
5、AUDIOVISUAL SERVICES F.700F.799 ISDN SERVICES F.800F.849 UNIVERSAL PERSONAL TELECOMMUNICATION F.850F.899 HUMAN FACTORS F.900F.999 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. F.741 (09/2005) i ITU-T Recommendation F.741 Service description and requirements for a
6、udiovisual on-demand services Summary Audiovisual on-demand services are one class of the generic multimedia services identified in ITU-T Rec. F.700. Following the methodology proposed in ITU-T Rec. F.701, this Recommendation describes the functional model, application scenarios, a variety of requir
7、ements, and interworking and interoperation of the audiovisual on-demand services. Source ITU-T Recommendation F.741 was approved on 13 September 2005 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. F.741 (09/2005) FOREWORD The International Telecommun
8、ication Union (ITU) is the United Nations specialized agency in the field of telecommunications. The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tariff questions and issuing Recommendations on them with
9、a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendations on these topics. The approval of ITU-T Recomm
10、endations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommendation, the expression “Administration“ is used for con
11、ciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure e.g. interoperability or applicability) and compliance with the Recommenda
12、tion is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compliance with the Recommendation is required of any party.
13、INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity or applicability of claimed Intellectual Property Right
14、s, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, implementors
15、 are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database. ITU 2005 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior written permission of ITU. ITU-T Rec. F.741 (
16、09/2005) iii CONTENTS Page 1 Scope 1 2 References. 1 2.1 Normative references 1 2.2 Informative references 1 3 Definitions 1 4 Abbreviations 2 5 Conventions 2 6 Prose description. 3 7 Functional model of audiovisual on-demand services 3 7.1 Functional model 3 7.2 Participants . 4 8 Description of au
17、diovisual on-demand service application scenarios 4 8.1 Point-to-point unicasting applications 4 8.2 Point-to-multipoint multicasting applications 5 8.3 Audiovisual download and value-added services. 6 9 Requirements for audiovisual on-demand services 6 9.1 Requirements for services 6 9.2 Requiremen
18、ts for management. 7 9.3 Requirements for navigation 7 9.4 Requirements for security authentication. 7 9.5 Requirements for accounting 7 9.6 Requirements for QoS 7 9.7 Requirements for DRM 8 10 Related applications 8 11 Interworking and interoperation . 8 11.1 Interworking and interoperation between
19、 different audiovisual on-demand service providers. 8 11.2 Interworking between audiovisual on-demand and audiovisual conferencing systems 9 ITU-T Rec. F.741 (09/2005) 1 ITU-T Recommendation F.741 Service description and requirements for audiovisual on-demand services 1 Scope This Recommendation des
20、cribes the audiovisual on-demand services and defines the functional model and application scenarios. Based on these descriptions, it gives the requirements for services, managements, etc. 2 References The following ITU-T Recommendations and other references contain provisions, which, through refere
21、nce 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; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most r
22、ecent edition of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 2.1 Normative refere
23、nces None. 2.2 Informative references ITU-T Recommendation F.700 (2000), Framework Recommendation for multimedia services. ITU-T Recommendation F.701 (2000), Guideline Recommendation for identifying multimedia service requirements. ITU-T Recommendation F.740 (1993), Audiovisual interactive services.
24、 ITU-T H-series Recommendations Supplement 1 (1999), Application profile Sign language and lip-reading real-time conversation using low bit-rate video communication. 3 Definitions This Recommendation defines the following terms: 3.1 authentication and authorization: Authentication and authorization
25、refers to validating the identities of users who want to use the services and authorizing the legal users to prevent unauthorized access to the services. 3.2 audiovisual multicasting: When users request the same content at the same time, the audiovisual on-demand services platform lists them in the
26、same multicasting group. The platform sends the requested content media streams to that multicasting group, the users within the same group then may receive the same requested contents. 3.3 audiovisual on-demand services: A kind of network-delivered service that offers the functionality of the home
27、VCR (as play only) without having a need to get a copy of the chosen material. 3.4 audiovisual on-demand services platform: The application environment which supplies audiovisual on-demand services to users. 2 ITU-T Rec. F.741 (09/2005) 3.5 audiovisual on-demand presented: One value-added service su
28、pplied by the audiovisual on-demand services platform. The person who consumes the content is not the person who requests it. The person who requests the content (as a gift to the viewer) pays for it instead of the person who consumes it. 3.6 download services: Users store the chosen contents in the
29、ir terminals by downloading them from service platforms in order to play them at any time they like. 3.7 electronic program guide (EPG): Electronic program guide is the assistance tool which helps users to look up the contents they want. It is a kind of metadata of contents which usually consists of
30、 program name, program provider, language used by program, etc. Service provider can determine the information the EPG delivers. 3.8 near VoD: Near VoD is a special multicast application that improves the availability of video information, without requiring a dedicated point-to-point connection to e
31、ach viewer. 3.9 information resources retrieval: It is the retrieval for contents by finding related contents based on the keywords such as, content titles, authors, schedules or actors names. 3.10 uniform service portal: A portal which provides all the users with audiovisual on-demand services info
32、rmation such as authentication and contents retrieval information. 3.11 VCR functions: The functionalities of video cassette recorder, such as select/cancel, start, stop, pause (with or without freeze frame), fast forward, reverse, scan forward or reverse (both with image), and setting and resetting
33、 memory marks. 4 Abbreviations This Recommendation uses the following abbreviations: CP Content Provider DRM Digital Right Management EPG Electronic Program Guide IPTV Internet Protocol Television PDA Personal Digital Assistant QoS Quality of Service SP Service Provider STB Set Top Box VCR Video Cas
34、sette Recorder VoD Video on Demand 5 Conventions In this Recommendation the following conventions are used: “shall“ indicates a mandatory requirement. “should“ indicates a suggested but optional course of action. “may“ indicates an optional course of action rather than a recommendation that somethin
35、g take place. ITU-T Rec. F.741 (09/2005) 3 6 Prose description Audiovisual on-demand services involve asymmetric interactive multimedia communications between users and machines (audiovisual resources) which may provide users with audiovisual information from all around the world, at any time, throu
36、gh telecommunication networks. Users can find the information needed with the assistance of a navigation subsystem. The audiovisual on-demand services platform sends contents information with some grade of guaranteed QoS after the users have chosen the service mode. Users can then use VCR-like funct
37、ionalities to view the received information. The contents provided by the audiovisual on-demand services platform may be textual, aural, graphical or imagery, or video information. Media resources may be stored at any locations on the networks. Audiovisual on-demand services platform integrates medi
38、a resources, performs DRM and provides navigation service and content delivery through telecommunication networks. Users may use audiovisual on-demand services at fixed or mobile locations, such as at homes, offices, or on moving trains. Users should be able to access broadband network environment w
39、ith streaming media communication capabilities to get audiovisual on-demand service applications using PC, STB plus TV set, mobile phone, PDA or other equipment. 7 Functional model of audiovisual on-demand services 7.1 Functional model Audiovisual on-demand services may provide information contents
40、stored at different locations of networks to users by managing and integrating information resources. Audiovisual on-demand services may provide content navigation and retrieval service, provide local caching for remote information resources, and have authentication and accounting functions and secu
41、rity mechanisms. Audiovisual on-demand services may provide IPTV, VoD, Near VoD and download services to users. The functional model of audiovisual on-demand services system is shown in Figure 1. Figure 1/F.741 Functional model of audiovisual on-demand services system An audiovisual on-demand servic
42、es system is made of content providers, service providers (control and management system and multi-audiovisual on-demand service providers) and end users. 4 ITU-T Rec. F.741 (09/2005) The control and management system provides the following operational support functions for audiovisual on-demand ser
43、vices: Operational support: it refers to user management, authentication and authorization, accounting and charging management functions; Service support: it refers to navigation, ordering contents, resources management, DRM and multicast control functions; Network support: it refers to functions su
44、ch as device management, optimization policy, system maintenance and network security. Multi-audiovisual on-demand services provide three modes of services: point-to-point unicasting services, point-to-multipoint multicasting services and download services. Using any one of these three modes of serv
45、ices, users can retrieve the desired contents and get related services. Because the techniques used for these three services modes are different, they may have different features: Point-to-point unicasting services: It takes client/server point-to-point configuration, such as VoD services. Each user
46、 has a unicasting media streaming. This mode of services supports VCR-like functionalities such as play, pause, replay, fast forward and fast reverse. Point-to-multipoint multicasting services: It takes point-to-multipoint configuration. The services platform multicasts media streams to a multicasti
47、ng group based on users requests. Users who are in the multicasting group receive the same media streams. This mode of services does not support VCR-like functionalities, but users can exit from the multicasting group during the use of the services. Download services: A kind of service which provide
48、s contents to users by downloading and storing. It may use distributed storage methods and multipoint download techniques to avoid a server bottleneck resulting from multiple pieces of content downloading at the same time. Service providers may provide all kinds of value-added services, such as audi
49、ovisual on-demand as a gift, gaming or pre-ordered contents. 7.2 Participants Participants of audiovisual on-demand services have the following three main roles as shown in Figure 1: Content Providers (CP): CP refers to the owner of information resources. They may be issuers of music, movies, live programs or common information resources (such as museums and public libraries). Generally speaking, content providers provide contents lists and information contents through networks or other paths to service providers, for users retriev
