ANSI ISO IEC 14478-2-1998 Information technology - Computer graphics and image processing - Presentation Environment for Multimedia Objects (PREMO) - Part 2 Foundation Component (A.pdf

1、INTERNATIONAL STANDARD ISOAEC 14478-2 First edition 1998-12-15 Information technology - Computer graphics and image processing - Presentation Environment for Multimedia Objects (PREMO) - Part 2: Foundation Component Technologies de /information - lnfographie et traitement dimages - Environnement de

2、prksentation dobjets multimkdia (PREMO) - Pat-tie 2: Composant fondamental Reference number ISOAEC 14478-2:1998(E) Adopted by INCITS (InterNational Committee for Information Technology Standards) as an American National Standard.Date of ANSI Approval: 3/31/99Published by American National Standards

3、Institute,25 West 43rd Street, New York, New York 10036Copyright 2002 by Information Technology Industry Council (ITI).All rights reserved.These materials are subject to copyright claims of International Standardization Organization (ISO), InternationalElectrotechnical Commission (IEC), American Nat

4、ional Standards Institute (ANSI), and Information Technology Industry Council(ITI). Not for resale. No part of this publication may be reproduced in any form, including an electronic retrieval system, withoutthe prior written permission of ITI. All requests pertaining to this standard should be subm

5、itted to ITI, 1250 Eye Street NW,Washington, DC 20005.Printed in the United States of AmericaISO/IEC 1447%2:1998(E) Contents Foreword. . V Introduction vi I Scope . l 2 Normative references. .1 3 Definitions . 1 3.1 PREMO Part I definitions I 3.2 Additional definitions. I 4 Symbols and abbreviations

6、. 3 5 Conformance . . 3 6 Foundation non-object types. .3 7 Foundation object types . 5 7.1 Introduction . .S 7.2 PREMO ob,jects and fundamental object behaviour .5 7.1. I Cre;ltion and destruction of objects. 5 72.2 Inquirim on types . 5 7.3 Simple PREMO objects .f 7 3.1 Structures. h 7.3 Callback

7、objects .h 7.5 Enhanced PREMO Objects . .7 7.5.1 Object properties. . 7 ISO/IEC 1998 All rights reserved. Unless otherwise specified. no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical. including photocopying and microfilm, without permiss

8、ion in writing from the publisher. ISO/IEC Copyright Office l Case postale 56 l CH-121 I Gentrh(c, object. . 47 0. I I .2 Tf,IeSrlIIronCtrh/t, object . 53 0. I I .3 TirwLw object . . 57 Y I I .4 TUIJSLJLYJ objccl . 58 _ Y. I Z Enhanced Property management. 59 9.12. I Pmprrrhzyu object 59 Y. 12.2 Pro

9、prrrConsrrtllrlI object 60 9. I3 Creating PREMO objects . 63 9 13. I GwrrcFco objecr . 63 0 I3 2 I;clc,or,rrftl,r object . 64 10 Component specification . 65 A Overview of PREJIO Foundation Object Types . . . . . . . . . . . . . . . . . . . . 66 ill ISO/IEC 14478-2:1998(E) 0 ISO/IEC B Extensibility

10、for PREMO objects. . .70 c An example for event-based synchronization. . .71 0 ISO/IEC ISO/IEC 14478-2: 1998(E) Foreword IS0 (the International Organization for Standardiration) and IEC (the International Electrotechnical Commission) form the specialized system for worldwlde standardi- zation. Natio

11、nal bodies that are members of IS0 or IEC participate in the development of International Standards through technical commlttees establtshed by the respective organization to deal with particular fields of techmcal activity. IS0 and IEC techmcal committees collaborate in fields of mutual interest. O

12、ther international organizations. government and non-governmental, in liaison with IS0 and IEC. also take part in the work. In the field of information technology, IS0 and IEC have established a joint technical committee ISO/IEC JTCI. Draft International Standards adopted by the joint technical comm

13、ittees are circulated to the national bodies for voting. Publication as an Interna- tional Standard requires approval by at least 75% of the national bodies casting a vote. ISO/IEC 14478-Z was prepared by Technical CommIttee ISO/IEC JTC I. Ifrnariorz techtolo. Subcommittee SC24. Computer ,qruphics u

14、ttd imqe processing. ISO/IEC 14478 consists of the following four parts under the general title Itfirmutiot trchtwlo, - Conlpurcr grrrphics rmd ittuqc prrtcessitrg - Pre.smubotl ctwirotl- ttlctt1.T for ttiultittwdic objects (PREMO). - Part 1: Futtdumettuls ofPREM0 - Purr 2: Fouttdutiotl Cotnpotwtlt

15、- Part 4: Mulritnediu S.statns .%nices - P-rlrt 3: Modellitlg, Retlderitig. ctnd Itlteructtot Cottpottettt Annexes A and B form an integral part of this part of ISOlIEC 14478. Annex C is for information only. ISO/IEC 14478-2: 1998(E) Introduction This part of ISO/IEC 14478 defines those object types

16、 and non-object types which be- long to the Foundation Component. Any conforming PREMO implementation shall support these object types. The description of object types categories are given first and then the foundation object types in each category are described. 0 ISO/IEC vi INTERNATIONAL STANDARD

17、0 ISO/IEC ISO/IEC 14478-2: 1998(E) Information technology - Computer graphics and image processing - Presentation Environment for Multimedia Objects (PREMO) - Part 2: Foundation Component 1 Scope This part of ISO/IEC 14478 lists an initial set of object types and non-object types useful for the cons

18、truction of, presentation of, and InteractIon with multimedia information. This part is dependent on the PREMO object model defined in clause 8 of ISOlIEC 1447% I The foundation component does not depend on any other components. 2 Normative references The following standards contain provisions which

19、. through reference in this text, constitute provisions of this part of ISO/IEC 14478. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agree- ments based on this part of this international standard are encouraged to investigate the

20、 possibility of applying the most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid International Standards. ISO/IEC I4478- I : 1998, Information technology - Computer graphics and image processing - Presentation Environment for Multimedia

21、 Objects (PREMO) - Part I: Fundamentals of PREMO. ISOIIEC 10744: 1992, Information lechnology - Coding of Moving Pictures and Associated Audio for Digital Storage up to uhnu I5 Mbit/s (MPEG). 3 Definitions 3.1 PREMO Part 1 definitions This part of ISO/IEC 13478 makes use of all terms defined in ISO/

22、IEC 13378-I (Fundamentals of PREMO). 3.2 Additional definitions For the purposes of this part of ISO/IEC 14478, the following definitions apply 3.2.1 basic data type: Non-object data type which cannot be expressed via other data types. Examples are integers, tloat- ing point numbers. 3.2.2 construct

23、ed data type: As opposed to basic data type: non-object data type which is constructed with the help of permitted type constructors using basic data types. 3.2.3 time: A non-object data type which is appropriate for the representation of real time In the execution environment. It is typIcally realiz

24、ed through either tlnat numbers or large (6-l bit) integers. ISO/IEC 14478-2: 1998(E) 0 ISO/IEC 3.2.4 extended coordinates: An extension of real. integer. or time coordinates with the symbols -oo and 00, and the nat- ural comparison operators. It gives a succinct way of describing unlimited interval

25、s on these coordinate systems. 3.2.5 key-value pair: A constructed data type, consisting of a key (described as a string) and a corresponding value. 3.2.6 foundation object type: Object types defined in the foundation component of PREMO. 3.2.7 structure: A category of object types in PREMO; these ob

26、jects are characterized through attributes only 3.2.7.1 structure tag: A synonym for an attribute for a structure. 3.2.8 property: Key with associated value or sequence of values, which can be attached to any PREMO object, and which can be inquired, possibly created and deleted through operations de

27、fined on the object. 3.2.8.1 read-only property: A property whose value or values cannot be set by operations of the object 3.2.9 fundamental object behaviour: Operations defined on the PREMOOOjrcr type; this type is the supertype of a PREMO object types. 3.2.10 finite state machine: Implementation

28、of an abstract finite state automaton 3.2.11 constraint: A constructed data type. consisting of a key-value pair and an associated constraint operation; this latter is used to compare the values, in case the keys are identical. 3.2.12 event: A constructed data type. serving as a basic building block

29、 for the PREMO Event Model, 3.2.12.1 event source: Object (instance) which creates events. This is a structure tag of an event. 3.2.12.2 event client: Object (instance) which consumes events. 3.2.12.3 event name: A means to denote and/or to refer to a specific event. This name is also referred to as

30、 evettl type, This is a structure tag of an event. X2.12.4 event data: List of non-object types in the form of key-value pairs attached to an event. This is a structure tag of an event. 3.2.13 event handler: An object which provides event processing services to other objects, X2.14 era: The base dat

31、e for all PREMO systems to measure the amount of elapsed time. This value is set to ()O:C)oam. 1 st January 1970. UTC. 3.2.15 reference point: A point In the internal coordinate system of a synchronizable objects, to which a synchronization element is attached. 3.2.16 synchronization element: Synchr

32、onization information for a synchronizable object; it contains information on an- other obJect and its operation which shall be Invoked if synchronization is set up. 3.3.17 capability: Description of the property values an object type can take for a specific key 3.3.18 native property value: Descrip

33、tion of the property value an object instance can take for a specific key. 3.3.19 private properties: Properties of the object which are not defined as part of the functional specification ofthe object, The following alphabetlcal list gives the sub-clause of each definition basic data type capabilit

34、y constraint constructed data type event event client event data event handler 3.2.1 3.3.17 3.2.11 3.2.2 3.2.12 3.2.12.2 3.2.12.4 3.2.13 7 0 ISO/IEC ISO/IEC 14478-2: 1998(E) event name event source event type era extended coordinates finite state machine foundation object type fundamental object beh

35、aviour key-value pair native property value private properties property readonly property reference point structure structure tag synchronization element time 3.2.12.3 3.2.12.1 3.2.12.3 3.2. I4 3.2.4 3.2.10 3.2.6 3.2.9 3.2.5 3.3.18 3.3.19 3.2.8 3.2.8.1 3.2.1s 3.2.7 3.2.7. I 3.2.16 3.2.3 4 Symbols an

36、d abbreviations AIFF: Audio Interchange File Format. FSM: Finite State Machine. IEC: International Electrotechnical Commission. IS: International Standard. ISO: International Organization for Standardization. MPEG: Moving Picture Experts Group. PREMO: Presentation Environments for Multimedia Objects

37、 2D: Two-dimensional. 3D: Three-dimensional. 5 Conformance A conforming implementation of the PREMO Foundation Component shall comply with the general conformance rules defined in clause 5 of lSO/IEC 14478-I and the component specification in clause 10. 6 Foundation non-object types The foundation n

38、on-object types in PREMO are defined in two categories: basic data types. and data types directly defined from these basic data types in terms of the notations described in clause A.2 of lSO/IEC 1147X- I. The basic data types are (with their type names): a) N: non-negative integer. ISO/IEC 14478-2:

39、1998(E) 0 ISO/IEC b) Z: integer. c) R: real number. d) Objecrfipe: a data type uniquely identifying an object type. e) Event/d: a data type uniquely identifying an event registration for a PREMO event handler. f) Time: a data type to measure progression of real world time. This type is either a real

40、 number or a (possibly large) inte- ger. The choice among these is implementation dependent. g) As described in 8.5 of ISO/IEC 14478- 1, for each object of type Tan object reference type, which is a non-object type, referring to object instances of type T, automatically exists in PREMO. As a notatio

41、nal convention, RejT denotes the non- object type of object reference referring to object instances of type T. The environment shall provide comparison facilities for each basic data type which unambiguously decide whether two data val- ues are identical or not. In the case of object references the

42、environment shall also include a facility to test whether two references refer to the same object instance or not, or whether the value of the object reference is NULLObject. How these facilities are re- alized depends on the programming language and the execution environment in which PREMO is imple

43、mented. Coordinate spaces can be “extended” to include positive and negative “infinity”. Although the underlying implementation may not have a direct representation of these types, the obvious extension of the notion of “greater than ” “smaller than”, etc., on these , types allows the behaviour of o

44、bjects to be defined more succinctly. The following extended coordinate space definitions are used: h) Extended real numbers: R_=Ru (-.-I i) Extended integers: z_=zu (-3-j j) Extended time: Time_ = Time u (-=-. -) The foundation object types. described in this part, make also use of a number of (con

45、structed) non-object types, defined formally in 9.2 (page 27). Some of these non-object types play a key role in the behavioural description of several object types; they are , to make the semantic description in clause 7 easier to follow. therefore also listed here - Boolean: Hnolerrrl I:= TRUE 1 F

46、ALSE - Character String: - Constraint specification for key-value pairs (used. for example, by property management. event handlers, and aggregate object types): 3 0 ISO/IEC ISO/IEC 14478-2: 1998(E) ConstraintOp := Equal ( NotEqual 1 GreaterThajt 1 GreaterThanOrEqual 1 LessThan / LessThanOrEqual /Pre

47、fix I Suffix 1 NotPrefix I NotSuffix 1 Includes 1 Excludes Values in an operation request are constrained to values which satisfy these type constraints and the constructions defined in clause A.2 of ISO/IEC 14478-I (see also 8.6 of ISO/IEC 14478-l). No particular representation for these values is

48、mandated by the PREMO functional specification. although bindings of PREMO to programming languages or to distributed programming paradigms may specify such formats. 7 Foundation object types 7.1 Introduction Fourzdatiorl objects types are those which support a fundamental set of services suitable f

49、or use by a wide variety of higher level components. PREMO conformance rules require that, whenever a PREMO implementation includes these objects. they be in- cluded in the manner specified in this clause. This is the basis for interoperability. The following criteriaare used to identify foun- dation objects: a) they are used by a majority of higher level components; b) together they provide an adequate minimal functional set; c) they are needed to support output on widely available presentation resources; d) algorithms exist for decompos