1、 STD*ITU-T RECMN T.173-ENGL 1997 i8bZ.571 Ob41377 358 INTERNATIONAL TELECOMMUNICATION UNION ITU=T TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU T.173 (07/97) SERIES T: TERMINALS FOR TELEMATIC SERVICES MHEG-3 script interchange representation ITU-T Recommendation TA73 (Previously CCITT Recommendati
2、on) STDDITU-T RECMN T.173-ENGL 1797 9BbZ571 Ob91378 27q ITU-T T-SERIES RECOMMENDATIONS TERMINALS FOR TELEMATIC SERVICES For further details, please refer to ITU-T List of Recommendations. STDmITU-T RECMN T-173-ENGL 1777 4Bb2571 Ob41377 120 D ITU-T RECOMMENDATION T.173 MHEG-3 SCRIPT INTERCHANGE REPRE
3、SENTATION Source ITU-T Recommendation T.173 was prepared by ITU-T Study Group 16 (1997-2000) and was approved under the WTSC Resolution No. 1 procedure on the 10th of July 1997. FOREWORD ITU (International Telecommunication Union) is the United Nations Specialized Agency in the field of telecommunic
4、ations. The ITU Telecommunication 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 Teleco
5、mmunication Standardization 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 IT-T is covered by the procedure laid down in W
6、TSC Resolution No. 1. In some areas of information technology which fall within IT-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 adm
7、inistration and a recognized 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
8、or applicability of claimed 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 IT hadhad not received notice of intellectual property, protected by patents, which may be req
9、uired to implement this 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 ITU 1998 All rights reserved. No part of this publication may be reproduced or utilized in any form or
10、 by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the ITU. 11 Recommendation T.173 (07/97) - - STD-ITU-T RECMN T*L73-ENGL I997 48b257L ObllL38I 889 . 1 2 3 3.1 3.2 4 5.1 5.2 5.3 5.4 6 6.1 6.2 6.3 7 7.1 7.2 7.3 8 8.1 8.2 8.3 CONTENTS Pag
11、e Scope Normative references Definitions Definitions Abbreviations . General . Information object conformance 5.1.1 Profiles 5.1.2 Encoding 5.1.3 Syntax 5.1.4 Semantics Implementation conformance . 5.2.1 Conformance requirements . 5.2.2 Conformance documentation Application conformance . Test Method
12、s Overview Description methodology . Data processing operations . Access to external data and functions . MHEG/MHEG-3 relationship MHEG entities Functional entities MHEG-SIR script interpreter . Elements of MHEG-SIR . Data types . 8.1.1 Predefined types 8.1.2 Declared constructed types Data . 8.2.1
13、Immediate values . 8.2.2 Constants . 8.2.3 Variables Functions 8.3.1 Routines . Recommendation T.173 (07/97) . 1 1 7 8 8 8 8 8 8 9 9 9 10 10 10 10 11 12 12 12 12 13 13 13 16 18 18 19 19 20 20 . 111 8.4 8.5 8.6 9 9.1 9.2 9.3 9.4 9.5 10 10.1 10.2 10.3 10.4 10.5 iv 8.3.2 Services . 8.3.3 Predefined fun
14、ctions Messages . 8.4.1 Package exceptions . 8.4.2 Predefined messages . Instructions . Identifiers 8.6.1 Type identifiers . 8.6.2 Data identifiers 8.6.3 Function identifiers . 8.6.4 Message identifiers The MHEG-SIR virtual machine Structure of the MHEG-SIR virtual machine . Structures and notations
15、 . 9.2.1 Table 9.2.2 Stack 9.2.3 Parameter stack . 9.2.4 Queue 9.2.5 Data representation Memory areas . 9.3.1 Mh-script memory areas 9.3.2 Rt-script memory areas . Script statuses . 9.4.1 Mh-script statuses 9.4.2 Rt-script statuses . Processing units 9.5.1 Message reception . 9.5.3 Rt-script initial
16、ization 9.5.4 Rt-script execution unit . 9.5.2 Mh-script initialization 9.5.5 MHEG-SIR instruction execution unit Provisions for run-time environment access General model Declaration of IDL interfaces . Invocation of external operations in an MHEG-SIR program . Handling of external exceptions in an
17、MHEG-SIR program . Invocation of external operations by an MHEG-3 engine Recommendation T.173 (07/97) Page 21 21 22 22 22 22 23 23 23 23 24 24 24 25 25 25 25 25 26 27 27 29 33 33 33 34 34 35 36 36 36 37 37 37 38 38 39 - STD-ITU-T RECMN T-173-ENGL 1777 W 48b2571 UbliI1303 b51 i0.6 Handling of externa
18、l exceptions by an MHEG-3 engine . 10.7 Platform mapping specifications 11 1 1.1 Provisions for MHEG object manipulation Invoking MHEG actions . 1 1.1.1 1 1.1.2 Exchange of information with MHEG objects Sending messages to other scripts . Receiving MHEG messages . MHEG-3 API run operations 1 1.2 1 1
19、.2.1 11.2.2 MHEG API exceptions 12 MHEG-SIR declarations 12.1 Type declaration . 12.1.1 Type identifier . 12.1.2 Type description 12.2 Constant declaration . 12.2.1 Data identifier 12.2.2 Type identifier . 12.2.3 Constant value . 12.3 Global variable declaration . 12.3.1 Data identifier 12.3.2 Type
20、identifier . 12.3.3 Constant reference . 12.4 Package declaration 12.4,l Package identifier 12.4.2 Name . 12.4.3 Service description 12.4.4 Exception description 12.5 Handler declaration . 12.5.1 Message identifier . 12.5.2 Function identifier . 12.6 Routine declaration . 12.6.1 Function identifier
21、. 12.6.2 Type identifier . 12.6.3 Parameter description 12.6.4 Local variable declaration . 12.6.5 Program code . 13 MHEG-SIR instructions . Page 39 39 40 40 40 40 40 41 41 41 42 42 42 43 43 44 44 44 44 45 45 45 45 46 46 47 48 48 48 48 49 49 49 49 50 50 V Recommendation T.173 (07/97) 13.1 Presentati
22、on methodology 13.1.1 Error conditions . 13.1.2 Formal specification 13.1.3 Data table notation 13.1.4 Template instruction notation 13.1.5 Primitives Classification of MHEG-SIR instructions 13.3 Description of instructions . 13.3.1 No operation 13.3.2 Yield 13.3.3 Re turn 13.2 13.3.4 Free 13.3.5 No
23、t . 13.3.6 Or . 13.3.7 Exclusive or . 13.3.8 And 13.3.9 Equal reference 13.3.10 Equal 13.3.11 Less th an 13.3.12 Greater than . 13.3.13 Add 13.3.14 Subtract 1 3.3.1 5 Multiply . 13.3.16 Divide 13.3.17 Negate 13.3.1 8 Remainder . 13.3.19 Duplicate . 13.3.20 Convert 13.3.21 Jump on tnie 13.3.22 Jump o
24、n false . 13.3.23 Jump 13.3.24 Shift . 13.3.25 Get object reference . 13.3.26 Longjump on true . 13.3.27 Long jump on false 13.3.28 Long jump . 13.3.29 Call 1 3.3.3 O External call . Page 50 51 51 51 52 52 52 54 54 54 55 55 56 56 57 57 57 58 58 59 59 59 60 60 60 61 61 61 62 62 63 63 63 64 64 65 65 6
25、6 vi Recommendation T.173 (07197) 13.4 14 14.1 14.2 14.3 14.4 14.5 14.6 13.3.3 1 Push . 1 3.3.32 Push reference . 13.3.33 Push immediate . 13.3.34 Pop . 13.3.3 5 Pop reference . 13.3.36 Pop contents 13.3.37 Allocate . 1 3.3.3 8 Increment . 1 3.3.3 9 Decrement . 13.3.40 Get . 13.3.4 1 Get contents .
26、13.3.42 Set 13.3.43 Set contents . Type conversion rules . 13.4.1 Reversible conversions 13.4.2 Lossless extensions . 1 3.4.3 Lossy extensions . 13.4.4 Truncations to boolean 13.4.5 13.4.6 Truncations from floating-point to integer Truncations between integer or between floating-point types IDL mapp
27、ing to MHEG-SIR IDL specifications IDL interfaces and modules IDL operations. . 14.3.1 Operation name . 14.3.2 Operation parameters 14.3.3 Implicit parameter . 1 4.3.4 Return value IDL attributes 14.4.1 Accessor 14.4.2 Modifier . 14.4.3 Readonly attribute . IDL inherited operations . 14.6.1 Exceptio
28、n name . 14.6.2 Exception members . 14.6.3 Implicit member IDL exceptions . Recommendation T.173 (07/97) Page 68 68 68 69 69 69 70 70 71 71 72 73 74 75 75 75 76 76 76 76 76 77 77 77 77 77 77 78 78 78 78 78 78 78 78 78 79 vii STD-ITU-T RECMN T-173-ENGL 1777 Li8b2591 ObLi138b 3b0 14.7 14.8 15 15.1 15.
29、2 15.3 15.4 IDL types 14.7.1 char type 14.7.2 enum type 14.7.3 Constructed types 14.7.4 any type . 14.7.5 Restrictions on types . IDL constants The MHEG-3 API ScriptInterpreter object . 1 5.1.1 kill operation . 1 5.1.2 prepare operation . MhScript object 1 5.2.1 destroy operation . 15.2.2 new operat
30、ion RtScript object 15.3.1 15.3.2 15.3.3 15.3.4 15.3.5 15.3.6 15.3.7 15.3.8 15.3.9 delete operation . setpriority operation getpriority operation setData operation . getData operation allocate operation free operation . stop operation reInit operation 15.3.1 O getRtScriptStatus operation . 1 5.3.1 1
31、 open operation . RoutineInvocation object 15.4.1 close operation . 15.4.3 setparameter operation 15.4.5 run operation . 1 5.4.6 reset operation . 1 5.4.7 getInvocationStatus operation . 15.4.2 routine-id readonly attribute . 15.4.4 getprototype operation Annex A . ASN . 1 specification of interchan
32、ged scripts . Page 79 79 79 79 80 80 80 80 81 81 81 82 82 82 83 83 83 84 84 84 85 85 86 86 87 87 87 87 88 88 89 89 90 90 90 . VI11 Recommendation T.173 (07/97) Page Annex B - Coded representation of interchanged scripts B. 1 Coding for interchanged scripts 94 B.2 Coding for the program code 94 B.2.1
33、 Instruction op-codes 95 B.2.2 Instruction operands 95 94 Annex C - MHEG-SIR predefined elements C.l Predefined types . 1 O0 C. 1.1 Primitive types 1 O0 C. 1.2 MHEG API types 1 O0 C.2 Predefined functions . 101 C.2.1 MHEG API operations 101 C.2.2 MHEG-3 API operations . 101 (2.3 Predefined messages
34、. 102 C.3.1 MHEG-3 API operations . 102 C.3.2 The InstructionExecutionError exception . 102 99 C.3.3 MHEG-3 API exceptions 103 C.3.4 MHEG API exceptions 103 Annex D - IDL Platform mapping specification form 103 Annex E - MHEG API definition process . E. 1 Generic API definition framework . E. 1.1 E.
35、 1.2 IDL elements output by MHEG API definition process . E. 1.3 E. 1.4 General structure of the MHEG API . E. 1.5 IDL non-object datatype definition . E. 1.6 IDL interface definition. E.1.7 IDL attribute definition . E. 1.8 IDL operation definition E. 1.9 IDL exception definition . MHEG API mapping
36、 to MHEG-SIR . MHEG elements input to MHEG API definition process . Requirements on the MHEG API definition process E.2 1 o5 105 105 105 105 107 107 112 113 113 116 117 11s Annex F - IDL specification of the MHEG-3 API parts of ISO/IEC 13522) . Relationships with ITU-T Rec. T. 17 1 (and ISO/IEC 13 5
37、22- i) . Relationships with ITU-T Rec. T.172 (and ISO/IEC 13522-5) . Appendix I - MHEG-SIR syntax (EBNF notation) Annex G - Relationships with other ITU-T Recommendations of the T. 170-Series (and G. 1 G.2 119 119 120 121 Recommendation T.173 (07/97) ix - STD-ITU-T RECMN T.173-ENGL 1777 I 48bZ.571 O
38、b41388 133 Appendix II . Textual notation for MHEG-SIR scripts Appendix III . MHEG entities III . 1 MHEG objects 111.2 Mh-objects 111.3 Rt-objects 111.4 Interchanged MHEG objects Appendix IV . Main features of MHEG-SIR IV . 1 Features of using applications IV . 1.1 Manipulation of MHEG entities IV .
39、 1.2 Computations, variable handling and control structures . IV . 1.3 External device control IV . 1.4 Data acquisition . IV.1.5 Access to external data IV . 1.6 Access to arbitrary external run-time services IV.2 Functional features . IV.2.1 Data processing operations IV.2.2 Access to external dat
40、a and functions . IV.3 Technical features lV.3.1 Hardware independence IV.3.2 Final form representation IV.3.3 Compactness IV.3.4 Ease of implementation . IV.3.5 Interpretation efficiency IV.3.6 Openness and extensibility IV.3.7 Non-revisability . IV.3.8 IV.3.9 Semantic validation for quality of ser
41、vice purposes . . Provisions for real-time interchange . IV.3.1 O Syntax checkability (with regard to contamination hazards) IV.3.11 Non-proprietary representation . IV.3.12 Secure script processing Page 123 126 126 127 127 127 128 128 128 128 128 129 129 129 129 129 130 130 131 131 131 132 132 132
42、132 132 132 132 133 133 X Recommendation T.173 (07/97) STD-ITU-T RECMN T.173-ENGL 1777 m 48bZ571 Ob41387 07T Introduction This Recommendation, which is equivalent to ISO/IEC 13522-3, is a generic Recommendation which extends the coded representation of the MHEG script object class defined in ITU-T R
43、ecommendations of the T.170-SeriesY including T.171 and T.172. It specifies the MHEG script interchange representation (MHEG-SIR) for the contents of script objects, i.e. the encoding of the script data component of the MHEG script class. The ITU-T Recommendations of the T. 170-Series include the fo
44、llowing approved Recommendations: - - T. 170 (1 998), Framework of the T. 1 70-Series of Recommendations. T. 17 1 (1 996), Protocols for interactive audiovisual services: Coded representation of multimedia and hypermedia objects. T. 172 (1998), MHEG-5 - support for base-level interactive application
45、s. T. 173 (1 997), MHEG-3 script interchange representation. T. 174 (1996), Application programming interface (APO for MHEG-I. T. 175 (1998), Application programming interface (APO for MHEG-5. T. 176 (1 998), API for digital storage media command and control (DSM-CC). - - - - - Some ITU-T Recommenda
46、tions of the T.170-Series are equivalent to ISO/IEC 13522 parts. This standard consists of the following parts, under the general title: Information technology - Coding of multimedia and hypermedia information: - - - - - Annexes A to G form an integral part of this Recommendation. Appendices I to IV
47、 are for information only. Part 1 : Base notation; Part 3 : MHEG script interchange representation; Part 4: Registration procedure for MHEG format identifier; Part 5 : Support for base-level interactive applications; Part 6: Support for enhanced interactive applications. Recommendation T.173 (07/97)
48、 xi STDmITU-T RECMN T-173-ENGL 1977 D Lidb2571 Ob41370 891 W Recommendation T.173 MHEG-3 SCRIPT INTERCHANGE REPRESENTATION (Geneva, 1997) 1 Scope The scope of this Recommendation is to extend the coded representation of the MHEG script object class defined by ITU-T Rec. T.171 (and ISODEC 13522-1) 5
49、and ITU-T Rec. T.172 (and ISODEC This Recommendation specifies the MHEG Script Interchange Representation (MHEG-SIR) for the contents of script objects, i.e. the encoding of the script data component of the MHEG script class. MHEG engines are system or application components that handle, interpret and present MHEG objects. This Recommendation also specifies the semantics of interchanged scripts. These semantics are defined in terms of minimum requirements on the behaviour of MHEG engines that support the interpretation of interchanged scripts. T
