1、 International Telecommunication Union ITU-T H.324TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (04/2009) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Systems and terminal equipment for audiovisual services Terminal for low bit-rate multimedia communication Re
2、commendation ITU-T H.324 ITU-T H-SERIES RECOMMENDATIONS AUDIOVISUAL AND MULTIMEDIA SYSTEMS CHARACTERISTICS OF VISUAL TELEPHONE SYSTEMS H.100H.199 INFRASTRUCTURE OF AUDIOVISUAL SERVICES General H.200H.219 Transmission multiplexing and synchronization H.220H.229 Systems aspects H.230H.239 Communicatio
3、n procedures H.240H.259 Coding of moving video H.260H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture for audiovisual and multim
4、edia services H.360H.369 Supplementary services for multimedia H.450H.499 MOBILITY AND COLLABORATION PROCEDURES Overview of Mobility and Collaboration, definitions, protocols and procedures H.500H.509 Mobility for H-Series multimedia systems and services H.510H.519 Mobile multimedia collaboration ap
5、plications and services H.520H.529 Security for mobile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559 Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAN
6、D, TRIPLE-PLAY AND ADVANCED MULTIMEDIA SERVICES Broadband multimedia services over VDSL H.610H.619 Advanced multimedia services and applications H.620H.629 IPTV MULTIMEDIA SERVICES AND APPLICATIONS FOR IPTV General aspects H.700H.719 IPTV terminal devices H.720H.729 IPTV middleware H.730H.739 IPTV a
7、pplication event handling H.740H.749 IPTV metadata H.750H.759 IPTV multimedia application frameworks H.760H.769 IPTV service discovery up to consumption H.770H.779 For further details, please refer to the list of ITU-T Recommendations. Rec. ITU-T H.324 (04/2009) i Recommendation ITU-T H.324 Terminal
8、 for low bit-rate multimedia communication Summary Recommendation ITU-T H.324 describes terminals for low bit-rate multimedia communication, utilizing ITU-T V.34 modems operating over the general switched telephone network (GSTN), I.400-series user-network interface for integrated services digital n
9、etwork (ISDN) or an appropriate wireless interface for mobile networks. ITU-T H.324 terminals may carry real-time voice, data and video, or any combination, including videotelephony. ITU-T H.324 terminals may be integrated into personal computers or implemented in stand-alone devices such as videote
10、lephones. Support for each media type (voice, data, video) is optional, but if supported, the ability to use a specified common mode of operation is required, so that all terminals supporting that media type can interwork. This Recommendation allows more than one channel of each type to be in use. O
11、ther Recommendations in this series include Recommendation ITU-T H.223 (multiplex), Recommendation ITU-T H.245 (control), Recommendation ITU-T H.263 (video codec) and Recommendation ITU-T G.723.1 (audio codec). This Recommendation makes use of the logical channel signalling procedures of Recommendat
12、ion ITU-T H.245, in which the content of each logical channel is described when the channel is opened. Procedures are provided for expression of receiver and transmitter capabilities, so transmissions are limited to what receivers can decode, and so that receivers may request a particular desired mo
13、de from transmitters. Since the procedures of this Recommendation are also planned for use by Recommendation ITU-T H.310 for ATM networks, and Recommendation ITU-T H.323 for non-guaranteed bandwidth LANs, interworking with these systems should be straightforward. ITU-T H.324 terminals may be used in
14、 multipoint configurations through multipoint control units (MCUs), and may interwork with ITU-T H.320 terminals on the ISDN, as well as with terminals on wireless networks. Annex A defines the data protocol stack for use with the ITU-T H.324 control channel. Annex B defines high-level data link con
15、trol (HDLC) frame structure transparency for asynchronous transmission. Annex C defines the use of ITU-T H.324 terminals in error-prone transmission environments (“also referred to elsewhere as ITU-T H.324/M“). Annex D defines the use of ITU-T H.324 terminals on ISDN circuits (“also referred to else
16、where as ITU-T H.324/I“). Annex E defines timer T401 initialization for operation over geostationary-satellite channels. Annex F supports multilink operation on the GSTN and ISDN. Annex G defines the use of ISO/IEC 14496-1 (“MPEG-4 systems“) generic capabilities in ITU-T H.324 terminals. Annex H sup
17、ports multilink operation on error-prone mobile networks. Annex I defines the use of HTTP in ITU-T H.324 terminals, enabling non-conversational services with a user interface through web-like menus. Annex J summarizes the OIDs defined in this Recommendation and defines ITU-T H.324 generic capabiliti
18、es which are used in ITU-T H.245 signalling-based systems. Annex K defines the media-oriented negotiation acceleration (MONA) procedure, which allows media channels to be established in a fast and flexible manner. Annex L defines procedures to establish and carry text conversation sessions in the IT
19、U-T H.324 multimedia environment. Annex M defines the nature of ITU-T H.245 messages used by ITU-T H.324 endpoints. This revised version of this Recommendation introduces a number of enhancements and clarifications to the previous version, primarily the introductions of Annex K (MONA), Annex L (text
20、 conversation) and Annex M (ITU-T H.245 messages). Source Recommendation ITU-T H.324 was approved on 29 April 2009 by ITU-T Study Group 16 (2009-2012) under Recommendation ITU-T A.8 procedures. ii Rec. ITU-T H.324 (04/2009) FOREWORD The International Telecommunication Union (ITU) is the United Natio
21、ns specialized agency in the field of telecommunications, information and communication technologies (ICTs). 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 o
22、n them with 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
23、ITU-T Recommendations 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
24、used for conciseness 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 th
25、e Recommendation 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
26、 any party. 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 Pr
27、operty Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had received notice of intellectual property, protected by patents, which may be required to implement this Recommendation. However, impl
28、ementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2010 All rights reserved. No part of this publication may be reproduced, by any means whatsoever, without the prior writt
29、en permission of ITU. Rec. ITU-T H.324 (04/2009) iii CONTENTS Page 1 Scope 1 1.1 Block diagram and functional elements . 1 1.2 System elements outside the scope of this Recommendation 2 1.3 Functional elements covered by this Recommendation . 2 2 References. 3 2.1 Normative references 3 2.2 Informat
30、ive references 5 3 Definitions 6 4 Abbreviations and acronyms 7 5 Conventions 8 6 Functional requirements . 8 6.1 Required elements 8 6.2 Information streams 9 6.3 Modem 9 6.4 Multiplex 9 6.5 Control channel 11 6.6 Video channels . 14 6.7 Audio channels . 17 6.8 Data channels 18 7 Terminal procedure
31、s . 23 7.1 Phase A Call set-up of voiceband channel 23 7.2 Phase B Initial analogue telephony communication . 24 7.3 Phase C Establishment of digital communication, modem training 24 7.4 Phase D Initialization 25 7.5 Phase E Communication 25 7.6 Phase F End of session 26 7.7 Phase G Supplementary se
32、rvices and call clearing . 26 8 Interoperation with other terminals 27 8.1 Speech only terminals . 27 8.2 ITU-T H.320 multimedia telephone terminals over the ISDN . 27 8.3 Multimedia telephone terminals over mobile radio 27 9 Optional enhancements . 27 9.1 Data facilities 27 9.2 Encryption 28 9.3 Mu
33、ltilink . 30 iv Rec. ITU-T H.324 (04/2009) Page 10 Multipoint considerations . 30 10.1 Establishment of common mode 30 10.2 Multipoint rate matching 30 10.3 Multipoint lip synchronization . 30 10.4 Multipoint encryption . 31 10.5 Cascaded MCU operation . 31 11 Maintenance 31 11.1 Loopbacks for maint
34、enance purposes 31 Annex A Protocol stack for control channel . 33 A.1 General . 33 A.2 SRP mode . 34 A.3 LAPM/ITU-T V.42 mode . 36 A.4 WNSRP control frame signalling on the control channel 36 Annex B HDLC frame structure transparency for asynchronous transmission 40 Annex C Multimedia telephone ter
35、minals over error-prone channels 41 C.1 Abstract . 41 C.2 General . 41 C.3 Changes to procedures 42 C.4 Interworking . 42 C.5 Terminal procedures . 42 C.6 Initialization of multiplex level at the start of a session . 42 C.7 Dynamic change of level or option during session 44 C.8 Control channel defi
36、nition for mobile terminals 45 Annex D Operation on ISDN circuits (H.324/I) . 49 D.1 Scope 49 D.2 References 49 D.3 Definitions 49 D.4 Functional requirements . 49 D.5 Terminal procedures . 51 Annex E Timer T401 initialization for operation over geostationary-satellite channels 54 E.1 Introduction 5
37、4 E.2 Determination of timer value 54 E.3 Timer tuning procedure 55 Annex F Multilink operation. 56 F.1 Scope 56 F.2 References 56 F.3 Functional requirements . 56 F.4 Overview 56 F.5 Procedures 56 Rec. ITU-T H.324 (04/2009) v Page F.6 Maximum transmit skew 62 F.7 Sequence diagram for establishment
38、of multilink operation 62 Annex G Usage of ISO/IEC 14496-1 generic capabilities in ITU-T H.324 terminals . 64 G.1 Scope 64 G.2 References 64 G.3 General . 64 G.4 Choice of error protection for ISO/IEC 14496 data streams 64 G.5 Framing of ISO/IEC 14496-1 data streams 64 Annex H Mobile multilink opera
39、tion 65 H.1 Scope 65 H.2 Definitions and format conventions . 65 H.3 Functional requirements . 65 H.4 Overview 65 H.5 Mobile multilink layer specification 66 H.6 Procedures 69 H.7 Header modes . 72 Annex I Usage of HTTP generic capability in ITU-T H.324 terminals . 73 I.1 General . 73 I.2 Logical ch
40、annel for HTTP 74 I.3 HTTP generic capability . 74 I.4 References 74 Annex J ASN.1 OIDs defined in this Recommendation . 75 J.1 Summary of OIDs defined in this Recommendation . 75 J.2 Session reset capability identifier . 75 Annex K Media oriented negotiation acceleration procedure 76 K.1 Abstract .
41、 76 K.2 General . 76 K.3 References 76 K.4 Definitions and format conventions . 76 K.5 Terminal procedures . 77 K.6 MONA signalling . 77 K.7 Channel establishment method negotiation 80 K.8 Channel establishment via the signalling preconfigured channel (SPC) 88 K.9 Preconfigured channel establishment
42、 . 92 K.10 Accelerated ITU-T H.245 procedures 97 Annex L Text conversation in ITU-T H.324 101 L.1 Introduction 101 L.2 Scope 101 L.3 Definitions 101 vi Rec. ITU-T H.324 (04/2009) Page L.4 Procedures for ITU-T T.140 text conversation 101 L.5 Framing and buffering of ITU-T T.140 data 103 L.6 Presentat
43、ion considerations 103 Annex M ITU-T H.245 messages used by ITU-T H.324 endpoints . 106 Appendix I Bit and octet order 110 Appendix II ITU-T V.8 bis codepoints . 111 Rec. ITU-T H.324 (04/2009) 1 Recommendation ITU-T H.324 Terminal for low bit-rate multimedia communication 1 Scope This Recommendation
44、 covers the technical requirements for very low bit-rate multimedia telephone terminals operating over the general switched telephone network (GSTN). ITU-T H.324 terminals provide real-time video audio or data, or any combination, between two multimedia telephone terminals over a GSTN voice band net
45、work connection. Communication may be either 1-way or 2-way. Multipoint communication using a separate multipoint control unit (MCU) among more than two ITU-T H.324 terminals is possible. MCUs and other non-terminal devices are not bound by the requirements in this Recommendation, but they should co
46、mply where practical. The multimedia telephone terminals defined in this Recommendation can be integrated into personal computers (PCs) or workstations, or be stand-alone units. Interworking with visual telephone systems on the integrated services digital network (ISDN) (known as the ITU-T H.320-ser
47、ies of Recommendations) and on mobile radio networks are also covered. 1.1 Block diagram and functional elements A generic ITU-T H.324 multimedia videophone system is shown in Figure 1. It consists of terminal equipment, GSTN modem, GSTN network, multipoint control unit (MCU) and other system operat
48、ion entities. ITU-T H.324 implementations are not required to have each functional element. H.324(09)_F01Scope of ITU-T H.324MCUReceivepath delayModemcontrolV. 25 0ITU-T ModemV. 34 /V. 8ITU-T ITU-T GSTNnetworkVideo codecH.263/H.261ITU-T ITU-T Data protocolsV. 14 ,LAPM, etc.ITU-T Control protocolH.24
49、5ITU-T SRP/LAPMproceduresMultiplex/demultiplexH.223ITU-T System controlVideo I/O equipmentUser data applicationsT.120, etc.ITU-T Audio I/O equipmentAudio codecG.723.1ITU-T Figure 1 Block diagram for ITU-T H.324 multimedia system 2 Rec. ITU-T H.324 (04/2009) 1.2 System elements outside the scope of this Recommendation The following system elements are covered by other Recommendations or are not subject to standardization, and are therefore not defin
