1、BRITISH STANDARD BS ISO/IEC 14478-3:1998 Information technology Computer graphics and image processing Presentation Environment for Multimedia Objects (PREMO) Part 3: Multimedia Systems Services ICS 33.160.60; 35.140BSISO/IEC 14478-3:1998 This British Standard, having been prepared under the directi
2、onof the DISC Board, waspublished under the authorityof the Standards Committee and comes intoeffecton 15 March 1999 BSI 05-1999 ISBN 0 580 30077 3 National foreword This British Standard reproduces verbatim ISO/IEC 14478-3:1998 and implements it as the UK national standard. The UK participation in
3、its preparation was entrusted to Technical Committee IST/31, Computer graphics and image processing, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and ke
4、ep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European pub
5、lications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary pr
6、ovisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theISO/IEC ti
7、tle page, pages ii to iv, pages 1 to 63 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No. Date CommentsBSISO/IEC 14478-3
8、:1998 BSI 05-1999 i Contents Page National foreword Inside front cover Foreword iv Text of ISO/IEC 14478-3 1ii blankBSISO/IEC 14478-3:1998 ii BSI 05-1999 Contents Page Foreword iv Introduction 1 1 Scope 2 2 Normative references 3 3 Definitions 3 3.1 PREMO Part 1 definitions 3 3.2 PREMO Part 2 defini
9、tions 3 3.3 Additional definitions 4 4 Symbols and abbreviations 4 5 Conformance 5 6 Overview of the Multimedia Systems Services 5 6.1 Introduction 5 6.2 Object framework 5 6.3 Subtyping diagram 7 6.4 MSS object life cycle 8 7 Configuration objects 9 7.1 Introduction 9 7.2 Format objects 9 7.3 Trans
10、port and Media Stream Protocol objects 10 7.4 Quality of Service Descriptor objects 10 8 Stream Controls 11 8.1 StreamControl objects 12 8.2 SyncStreamControl objects 14 9 Devices, Resources 14 9.1 Virtual Resources 14 9.1.1 Configuration objects on virtual resources 15 9.1.2 Stream control 15 9.1.3
11、 Resource management 15 9.1.4 Quality of Service Management 16 9.2 Virtual Devices 17 9.2.1 Processing element 18 9.2.2 Ports 18 9.2.3 Streams 18 9.2.4 Port configurations 19 9.3 Virtual Connections 20 9.3.1 Examples for connection agreement 20 9.3.2 Connection establishment 21 9.3.2.1 Unicast and m
12、ulticast 21 9.4 Groups 22 9.4.1 Resource acquisition and end-to-end QoS 23 9.4.2 Stream control 23 9.5 Logical Devices 24 10 Functional specification 25 10.1 Introduction 25 10.2 Non-object data types 25 10.3 Exceptions 25 10.4 Structures 26 10.4.1 Port information structure 26 10.5 Configuration ob
13、ject 26 10.5.1 Format objects 26 10.5.1.1 Format object 26BSISO/IEC 14478-3:1998 BSI 05-1999 iii Page 10.5.2 Transport and Multimedia Stream Protocol objects 26 10.5.2.1 MultimediaStreamProtocol objects 26 10.5.2.2 IntraNodeTransport objects 27 10.5.2.3 InterNodeTransport objects 27 10.5.3 Quality o
14、f Service objects 27 10.6 Stream Controls 28 10.6.1 StreamControl object 28 10.6.2 SyncStreamControl object 29 10.7 Devices, resources 30 10.7.1 VirtualResource object 30 10.7.2 VirtualDevice object 32 10.7.3 Virtual connections 34 10.7.3.1 VirtualConnection object 34 10.7.3.2 VirtualConnectionMulti
15、cast object 35 10.7.4 Group object 36 10.7.5 LogicalDevice object 37 11 Component specification 37 Annex A (normative) Overview of PREMO MSS objects 39 Annex B (informative) A typical example scenario for MSS usage 41 Annex C (informative) Basic Devices 42 C.1 Format objects 44 C.1.1 Video formats 4
16、4 C.1.2 Audio formats 45 C.1.3 CATV format 45 C.1.4 MIDI format 46 C.2 Digital stream controls 46 C.3 Video and audio processing 46 C.3.1 Video processing 46 C.3.2 Audio processing 47 C.4 Specific devices 47 C.4.1 Defining a device 47 C.4.2 Video 47 C.4.3 Audio 47 C.4.4 Files 48 C.4.5 CD player 49 C
17、.4.6 CATV tuner 49 C.4.7 MIDI device 49 C.4.8 External resources 49 C.5 Functional Specification 49 C.5.1 Area of interest for video objects 50 C.5.2 Format objects 50 C.5.3 Digital Stream Control 54 C.5.4 Video and audio processing 55 C.5.5 Specific devices 56 Annex D (informative) Examples of virt
18、ual connection settings 61 D.1 Hardware connection example 61 D.2 Direct connection example 61 D.3 Local connection example 61 D.4 Network connection example 63 Descriptors: Data processing, information interchange, graphic data processing, image processing, video data, audio data, coding (data conv
19、ersion), coded representation.BSISO/IEC 14478-3:1998 iv BSI 05-1999 Foreword ISO (the International Organization for Standardization) and IEC (the International Electrotechnical Commission) form the specialized system for worldwide standardization. National bodies that are members of ISO or IEC part
20、icipate in the development of International Standards through technical committees established by the respective organization to deal with particular fields of technical activity. ISO and IEC technical committees collaborate in fields of mutual interest. Other international organizations, government
21、 and non-governmental, in liaison with ISO and IEC, also take part in the work. In the field of information technology, ISO and IEC have established a joint technical committee ISO/IEC JTC1. Draft International Standards adopted by the joint technical committees are circulated to the national bodies
22、 for voting. Publication as an International Standard requires approval by at least75% of the national bodies casting a vote. ISO/IEC 14478-3 was prepared by Joint Technical Committee ISO/IEC JTC1, Information technology, Subcommittee SC24, Computer graphics and image processing. This International
23、Standard currently consists of the following four parts under the general title Information technology Computer graphics and image processing Presentation environments for multimedia objects (PREMO): Part 1: Fundamentals of PREMO; Part 2: Foundation Component; Part 3: Multimedia Systems Services; Pa
24、rt 4: Modelling, Rendering, and Interaction Component. Annex A forms an integral part of this part of ISO/IEC 14478. Annex B to Annex D are for information only.BSISO/IEC 14478-3:1998 BSI 05-1999 1 Introduction The Multimedia Systems Services (MSS) component of PREMO provides a standard set of servi
25、ces that can be used by multimedia application developers in a variety of computing environments. Enabling multimedia applications in a heterogeneous, distributed computing environment is the design motivation for the MSS. This is an increasingly prevalent computing model, and a solution that meets
26、the needs of this environment can more easily be scaled to stand-alone systems than vice versa. The principal reasons for defining the MSS are: a) provide abstractions and mechanisms that make it possible for applications to deal with the problems of distributed multimedia computing successfully; b)
27、 facilitate the implementation of complex applications, such as video conferencing; c) provide abstractions that make it possible for applications to deal with media devices without regard to specific characteristics of the platform, attached devices, or the network(s) connecting the platforms and d
28、evices; d) to provide a standard methodology, especially for handling “live” data; e) insure scalability to large organizations; f) insure adequate performance in adverse conditions; g) facilitate Quality of Service commitments; and h) consider the time critical nature of the data. The primary goal
29、of the MSS is to provide an infrastructure for building multimedia computing platforms that support interactive multimedia applications dealing with synchronized, time-based media in a heterogeneous distributed environment. Operation in a distributed environment is important because of significant t
30、rends in the computer industry towards client/server and collaborative computing. Another significant trend is towards multimedia enabled computing. The inevitable result will be an intersection of these trends to produce a distributed multimedia environment with a topology similar to Figure 1. The
31、MSS is intended to address a broad range of application needs. It extends the multimedia capabilities of stand-alone computers to capabilities that are usable both locally and remotely. The Multimedia Systems Services gives applications the ability to handle: i) live data remotely; j) stored data re
32、motely; k) both live and stored data simultaneously; l) multiple kinds of data simultaneously; and m) new kinds of devices and media types. To provide support for remote media device control and remote media access that derive from the above application scenarios, the Multimedia System Services uses
33、 two distinct mechanisms. To support interaction with remote objects, the Multimedia Systems Services depends upon an underlying object model and infrastructure, as described in ISO/IEC14478-1 (PREMO). To support the media independent streaming of time critical data, the Multimedia Systems Services
34、defines a Media Stream Control. The MSS does not address: n) encryption and security; o) intellectual property rights and accounting; p) scripting; q) user interfaces; or r) sharing of data between applications.BSISO/IEC 14478-3:1998 2 BSI 05-1999 1 Scope This part of ISO/IEC14478 defines a standard
35、 set of multimedia system services that can be used by multimedia application developers in a variety of computing environments. The focus is on enabling multimedia applications in a heterogeneous, distributed computing environment. Throughout this part of ISO/IEC14478, this component will also be r
36、eferred to as “Multimedia Systems Services”, and abbreviated as MSS. Figure 1 Distributed multimedia environmentBSISO/IEC 14478-3:1998 BSI 05-1999 3 The Multimedia Systems Services constitutes a framework of “middleware” system software components lying in the region between the generic operating sy
37、stem and specific applications. As middleware, the Multimedia Systems Services marshals lower-level system resources to the task of supporting multimedia processing, providing a set of common services which can be used by multimedia application developers. The Multimedia Systems Services encompasses
38、 the following characteristics: a) provision of an abstract type for a media processing node, extensible through subtyping to support abstractions of real media processing hardware or software; b) provision of an abstract type for the data flow path or the connection between media processing nodes,
39、encapsulating low-level connection and transport semantics; c) grouping of multiple processing nodes and connections into a single unit for purposes of resource reservation and stream control; d) provision of a media dataflow abstraction, with support for a variety of position, time and/or synchroni
40、zation capabilities; e) separation of the media format abstractions from the dataflow abstraction; f) synchronous exceptions and asynchronous events; g) application visible characterization of object capabilities; h) registration of objects in a distributed environment by location and capabilities;
41、i) retrieval of objects in a distributed environment by location and constraints; j) definition of a Media Stream Protocol to support media independent transport and synchronization. The Multimedia Systems Services rely on the object model of ISO/IEC14478-1 (Fundamentals of PREMO) and the object typ
42、es and non-object data types defined in ISO/IEC14478-2 (PREMO Foundation Component). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO/IEC 14478. At the time of publication, the editions indicated were v
43、alid. All standards are subject to revision, and parties to agreements based on this part of this international standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid I
44、nternational Standards. ISO/IEC 14478-1:1998, Information technology Computer graphics and image processing Presentation Environment for Multimedia Objects (PREMO) Part 1: Fundamentals of PREMO. ISO/IEC 14478-2:1998, Information technology Computer graphics and image processing Presentation Environm
45、ent for Multimedia Objects (PREMO) Part 2: Foundation Component. ISO/IEC 14478-4:1998, Information technology Computer graphics and image processing Presentation Environment for Multimedia Objects (PREMO) Part 4: Modelling, Rendering, and Interaction Component. ISO/IEC 10918-1:1994, Information tech
46、nology Digital Compression and Coding of Continuous-Tone Still Images (JPEG). ISO/IEC 11172:1992, Information technology Coding of Moving Pictures and Associated Audio for Digital Storage Media at up to about 1.5Mbit/s (MPEG). 3 Definitions 3.1 PREMO Part 1 definitions this part of ISO/IEC 14478 mak
47、es use of all terms defined in ISO/IEC 14478-1 (Fundamentals of PREMO) 3.2 PREMO Part 2 definitions this part of ISO/IEC 14478 makes use of all terms defined in ISO/IEC 14478-2 (PREMO Foundation Component)BSISO/IEC 14478-3:1998 4 BSI 05-1999 3.3 Additional definitions For the purposes of this part o
48、f ISO/IEC 14478, the following definitions apply. 3.2.1 configuration objects collective name for format, quality of service descriptor, and media stream protocol objects 3.2.2 jitter delay variance 3.2.3 processing element (for virtual devices) conceptual entity describing the internal behaviour of
49、 virtual device objects 3.2.4 virtual connection adapter conceptual entity describing the configuration process performed by a virtual connection object 3.2.5 unicast connection one-to-one connection; an output port may be connected to one input port only, and an input port may be connected to one output port only 3.2.6 multicast connection one-to-many connection; an output port may be connected to several input ports, and an input port may be connected to several output ports the following alphabetical list gives the subclause
