1、 International Telecommunication Union ITU-T H.249TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (05/2006) SERIES H: AUDIOVISUAL AND MULTIMEDIA SYSTEMSInfrastructure of audiovisual services Communication procedures Extended user input indications ITU-T Recommendation H.249 ITU-T H-SERIES RECOMMENDA
2、TIONS 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 Communication procedures H.240H.259 Coding of moving video H.2
3、60H.279 Related systems aspects H.280H.299 Systems and terminal equipment for audiovisual services H.300H.349 Directory services architecture for audiovisual and multimedia services H.350H.359 Quality of service architecture for audiovisual and multimedia services H.360H.369 Supplementary services f
4、or 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 applications and services H.520H.529 Security for m
5、obile multimedia systems and services H.530H.539 Security for mobile multimedia collaboration applications and services H.540H.549 Mobility interworking procedures H.550H.559Mobile multimedia collaboration inter-working procedures H.560H.569 BROADBAND AND TRIPLE-PLAY MULTIMEDIA SERVICES Broadband mu
6、ltimedia services over VDSL H.610H.619 For further details, please refer to the list of ITU-T Recommendations. ITU-T Rec. H.249 (05/2006) i ITU-T Recommendation H.249 Extended user input indications Summary The current version of ITU-T Rec. H.245 defines a method of transferring user keystrokes in u
7、serInputIndication messages. That method allows implementation of simple user interfaces. Many endpoint devices are equipped with advanced keypads, touch pad input, etc., and require more sophisticated tools from the protocol. This Recommendation provides a means to add such user interface features
8、within the structure of H.245. The extensions defined in this Recommendation may be beneficial for several types of applications. For example: Video on demand navigating a menu (provided by the server) of possible steaming sources. Map navigation using navigation keys to move/zoom a map image provid
9、ed by the server. Source ITU-T Recommendation H.249 was approved on 29 May 2006 by ITU-T Study Group 16 (2005-2008) under the ITU-T Recommendation A.8 procedure. ii ITU-T Rec. H.249 (05/2006) FOREWORD The International Telecommunication Union (ITU) is the United Nations specialized agency in the fie
10、ld 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 a view to standardizing telecommunications on a worldwide basis. The Wo
11、rld 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 Recommendations is covered by the procedure laid down in WTSA Resolution 1. I
12、n 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 conciseness to indicate both a telecommunication administration and a reco
13、gnized 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 Recommendation is achieved when all of these mandatory provisions are met. The wo
14、rds “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. INTELLECTUAL PROPERTY RIGHTS ITU draws attention to the possibility tha
15、t 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 Rights, whether asserted by ITU members or others outside of the Recommendat
16、ion 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 are cautioned that this may not represent the latest information and a
17、re therefore strongly urged to consult the TSB patent database. ITU 2006 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. H.249 (05/2006) iii CONTENTS Page 1 Scope 1 2 References. 1 3 Terms and Defini
18、tions 1 4 Abbreviations 1 5 User interface features in H.245 . 2 6 Extension of userInputIndication 2 6.1 Extensibility mechanism 2 6.2 Capability signalling. 2 6.3 Hierarchy of user interface devices 2 Annex A Navigation key indications 3 A.1 Overview 3 A.2 Signalling in H.245. 3 Annex B Soft key i
19、ndications . 5 B.1 Overview 5 B.2 Signalling in H.245. 5 Annex C Indication of pointing device input 7 C.1 Overview 7 C.2 Signalling in H.245. 7 Annex D Modal interface messages 10 D.1 Overview 10 D.2 Signalling in H.245. 10 Appendix I ASN.1 OIDs defined in ITU-T Rec. H.249 . 12 ITU-T Rec. H.249 (05
20、/2006) 1 ITU-T Recommendation H.249 Extended user input indications 1 Scope This Recommendation defines a method for signalling advanced user interface inputs using the structure of H.245. This Recommendation defines a mechanism for extension of the userInputIndication message. The annexes to the Re
21、commendation define the extensions themselves. 2 References The following 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 Recommendati
22、ons and other references are subject to revision; users of this Recommendation 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 publis
23、hed. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. 1 ITU-T Recommendation H.245 (2006), Control protocol for multimedia communication. 2 ISO/IEC 10646:2003, Information technology Universal Multiple-Octet Coded Cha
24、racter Set (USC). 3 ITU-T Recommendation H.324 (2005), Terminal for low bit-rate multimedia communication. 4 ITU-T Recommendation H.323 (2006), Packet-based multimedia communications systems. 3 Terms and definitions This Recommendation defines the following terms: 3.1 client: An H.245 endpoint confo
25、rmant with this Recommendation which includes a user input device and transmits user action information to the server. 3.2 DTMF digits: The user input characters 0-9, *, and #. 3.3 server: An H.245 endpoint conformant with this Recommendation which receives user action information from the client. 3
26、.4 user interface device: A set of user interface elements such as keys, buttons, etc. or a physical input device. 3.5 user input operation: An operation which may be performed on an user interface device. 4 Abbreviations This Recommendation uses the following abbreviations: DTMF Dual Tone Multi-Fre
27、quency OID Object IDentifier 2 ITU-T Rec. H.249 (05/2006) 5 User interface features in H.245 The alphanumeric field of the H.245 userInputIndication message allows the indication of user input characters, where each character belongs to the generalString character set. The generalString character se
28、t consists of the characters defined in ISO/IEC 10646. The H.245 userInputCapability message provides a mechanism to signal which of several subsets of characters an endpoint has the capability to signal. The commonly supported character set is the set of characters 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, * a
29、nd # which are called “DTMF digits“ for historical reasons. 6 Extension of userInputIndication This Recommendation defines a mechanism to add user interface extensions to H.245. An extension can define a user interface device such as a particular set of related keys or a physical input device, or a
30、set of user input operations which can be performed on a user input device (see Annex D for example). 6.1 Extensibility mechanism User interface extensions are identified by OIDs. The OID is used to: signal support for extensions in terminalCapabilitySet using userInputCapability; indicate input fro
31、m a user interface device using userInputIndication; indicate an operation on a particular user interface device using userInputIndication. In the case of an operation, userInputIndication contains both the OID of the operation and the OID of the user interface device on which it is performed. Exten
32、sions defining user interface devices specify the set of possible user input indications from a device, operations which can be performed on the device and the place of the user input device in the hierarchy presented in 6.3. Extensions defining user input operations specify the set of the operation
33、s and the user input device on which they can be performed. 6.2 Capability signalling Each device using a particular extension of the userInputIndication shall signal support for such extension in the terminalCapabilitySet. If one of the communicating devices does not support a particular extension,
34、 then the closest mutually supported predecessor according to the hierarchy defined in 6.3 shall be used. 6.3 Hierarchy of user interface devices This clause defines a hierarchy of user interface devices defined in the annexes to this Recommendation. NOTE 1 This hierarchy should be updated for each
35、new user interface device definition added in future versions of this Recommendation. The root of the hierarchy defined here is the DTMF set of user input characters. All entities conformant with this Recommendation shall support the transmission of user input characters 0-9, *, and #. NOTE 2 Accord
36、ing to 6.5/H.324 and Annex A/H.323 the DTMF digits are supported by all H.324 and H.323 entities. ITU-T Rec. H.249 (05/2006) 3 If an endpoint supports a particular user interface device, it shall also support all the user interface devices on the path shown in Figure 1 between the supported user int
37、erface device and the DTMF digits. The OIDs for all these capabilities shall be specified in the terminalCapabilitySet message. The hierarchy is defined as shown in Figure 1: Figure 1/H.249 Hierarchy of user interface devices Annex A Navigation key indications A.1 Overview This annex defines a way o
38、f indicating navigation keystrokes. The navigation keys may be used to navigate maps, menus, etc. This set of keys includes: Right, Left, Up, Down, Select. The protocol defined in this annex defines: a mechanism to signal the capability to support navigation keys; a mechanism to transfer navigation
39、keystroke indications from a client to the server. A.2 Signalling in H.245 To indicate the capability to support the navigation keys feature, the Navigation Key capability identifier in Table A.1 shall be included in the capability.receiveUserInputCapability. genericUserInputCapability field of the
40、TerminalCapabilitySet message. To indicate a navigation keystroke, the Navigation Key OID in Table A.1 and the Key ID parameter in Table A.2 shall be included in a userInputIndication message. The Navigation Key OID shall be specified in the standard form of the messageIdentifier subfield in the gen
41、ericInformation field of the userInputIndication H.245 message. The messageContent subfield of the same genericInformation field shall include the Key ID parameter. 4 ITU-T Rec. H.249 (05/2006) Table A.1/H.249 “Navigation Key“ capability Capability name Navigation Key Capability class User Input cap
42、ability Capability identifier type Standard Capability identifier value itu-t (0) Recommendation (0) h (8) 249 navigation-key(1) maxBitRate This field shall not be included. collapsing This field shall not be included. nonCollapsing This field shall not be included. nonCollapsingRaw This field shall
43、 not be included. transport This field shall not be included. Table A.2/H.249 “Key ID“ parameter Parameter name Key ID Parameter description This parameter indicates which navigation key has been pressed on the terminal input device. The value of the parameter specifies the navigation key: Value of
44、1 Right Navigate Right Value of 2 Left Navigate Left Value of 3 Up Navigate Up Value of 4 Down Navigate Down Value of 5 Select Activate selected item or position All other values Reserved Parameter identifier value 1 Parameter status Mandatory Parameter type unsignedMin Supersedes None ITU-T Rec. H.
45、249 (05/2006) 5 Annex B Soft key indications B.1 Overview This annex defines a way of indicating soft key strokes. Soft keys are keys which have a dynamically assignable name. Such keys may be used for many different functions. To indicate to the human user what function a particular soft key curren
46、tly has, the server assigns a name to the key. This name is communicated from server to client using the indication defined in this annex. The way the name is communicated or displayed to the human user is not defined and is up to the specific implementation. To facilitate interoperability the value
47、s for the number of soft keys available for assignment on a terminal should be 2, 5 or 10. The protocol defined in this annex defines: a mechanism to signal the capability to support soft keys; a mechanism to transfer keystroke indications from the client to the server; a mechanism for the server to
48、 assign or change the name of a particular soft key on the client. B.2 Signalling in H.245 To indicate the capability to support the “soft keys“ feature the Soft Key capability identifier defined in Table B.1 shall be included in the capability.receiveUserInputCapability. genericUserInputCapability
49、field of the TerminalCapabilitySet message. The Number of Soft Keys parameter defined in Table B.2 shall be specified as the collapsing capability parameter. It shall indicate the number of supported Soft Keys. There are two indications defined in this annex. One indication is used to assign a name to a key and is sent by the server to the client. The other indicates the keystrokes and is sent by the client to the server. To indicate the change or the assignment of the name of a soft k
