ISO/IEC 14478-1:1998

INTERNATIONAL ISOAEC
STANDARD
First edition
1998-12-15
Information technology - Computer,
graphics and image processing -
Presentation Environment for Multimedia
Objects (PREMO) -
Part 1:
Fundamentals of PREMO
Technologies de Yin forma tion - Infographie et traitement d ’images -
Environnement de pr&entation d ’objets multimedia (PREMO) -
Partie 1: Principes fondamentaux de PREMO

ISO/IEC 14478=1:1998(E)
Page
Contents
....
.....................................................
Foreword.
Introduction.i v
...........................................................
1 Scope
2 Normative references. .
3 Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
4 Symbols and abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
5 Conformance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
......................................... 7
6 Requirements for PREMO
6.1 Introduction .
............................................... .8
6.2 Extensibility
Configurability . .8
6.3
Incremental, separable development . .8
6.4
Simplicity . .8
6.5
Easeofuse . .8
6.6
Otherinfluences . .9
6.7
............................... 9
6.7.1 Application development environment
.......................................... .9
6.7.2 Execution environment
...9
6.8 Functionality .
.9
6.8.1 Introduction. .
............................................. .9
6.8.2 Computer graphics
................................................. .9
6.8.3 User interfaces
0 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, electronie or mechanical, including photocopying and microfilm, without
permission in writing from the publisher.
ISO/IEC Copyright Office l Case postale 56 l CH-121 1 Geneve 20 l Switzerland
Printed in Switzerland
ii
ISO/IEC 14478-1: 1998(E)
0 ISO/IEC
6.8.4 Dynamit interactive graphics .
6.8.5 Animation .
6.8.6 Audi0 .
........................................................ 10
6.8.7 Video
.......................................... 10
6.8.8 Other and future media
6.8.9 Co=--representations .
........................................ 10
6.8.10 Cooperating applications
7 Architecture of PREMO .
............................................... 10
7.1 Introduction
7.2 The Standards perspective .l 1
....................................
7.3 The functional perspective .ll
...................................
7.3.1 Introduction. .
7.3.2 Description techniques .
7.3.3 The Object model .
7.3.4 Components .
7.4 The System perspective. 12
.....................................
Configuring PREMO-based applications. 12
7.4.1 .
7.4.2 Distributed multimedia. .
7.4.3 Communication in PREMO .
(3 Object model . . . ’ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
8.1 Introduction. . .1 13
8.2 Basicconcepts . 13
8.3 Non-objecttypes . 13
8.4 Objecttypes . 14
8.5 Object identity and Object reference . 14
8.6 Operations .
8.7 Subtyping and inheritance. .
8.7.1 Overview . 15
8.7.2 Subtyping 15
.....................................................
8.7.3 Inheritance .
8.7.4 Operation dispatching. .
8.8 Abstract Types. 18
............................................
8.9 Operation request semantics 18
..................................
8.10 Protected operations 19
........................................
8.11 Object and Object reference life cycles . 19
8.12 Exceptions. 20
...............................................
9 Mow PREMO components are described. . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
A Notational conventions . 22
A. 1 Type declarations 22
..........................................
A.2 Data type definitions . 22
A.2.1 Simple data type definitions 22
......................................
A.2.2 Constructed type definitions 24
.......................................
A.3 Object type definitions . 25
Definition of finite state machines 26
A.4 .
Reference to operations and objects 27
AS .
Shorthands for Operation specifications 27
A.6 .
A.6.1 State transition operations of finite state machines . 28
A.6.2 Sequential composition of operations. . 28
Specification of components and profiles. 29
A.7 .
B Generic types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
C Graphical conventions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
C. 1 Graphical conventions for generic types. . . . . . . . . . . . . . . . . . . . . . . . . 36
iii
ISO/IEC 14478-1: 1998(E) 0 ISO/IEC
Foreword
ISO (the International Organization for Standardization) and IEC (the International
Electrotechnical Commission) form the specialized System for worldwide standardi-
zation. National bodies that are members of ISO or IEC participate 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 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 JTC 1. Draft International Standards adopted by the joint technical
committees 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 1 was prepared by Joint Technical Committee ISO/IEC JTC 1, Infor-
mation technology, Subcommittee SC24, Computer graphics and image processing.
ISO/IEC 14478consists of the following Parts under the general title Information tech-
nology - Computer graphics and image processing - Presentation Environment for
Multimedia Objects (PREMO):
- Part 1: Fundamentals of PREMO
Part 2: Foundation Component
- Part 3: Multimedia Systems Services
Part 4: Modelling, Rendering, and Interaction Component
Additional Parts may be defined as this work Progresses.
Annexes A and B form an integral part of this part of ISO/IEC 14478. Annex C is for
information only.
ISO/IEC 14478-1: 1998(E)
0 ISO/IEC
Introduction
The need for a coordinated method for addressing all aspects of the construction of,
presentation of, and interaction with multimedia objects has led to the standardization
of this Presentation Environment for Multimedia Objects. Multimedia means objects
consisting of still Computer graphics, moving Computer graphics (animation), synthet-
ic graphics of all types, audio, still images, moving images (including Video), images
coming from imaging operations, and any other content type or combination of con-
tent types that tan be “presented ”. ISO/IEC 14478 is extensible and configurable, and
allows the separate, incremental development of additional standardized and non-
standardized components to meet the needs of application communities.
PREMO currently consists of the following Parts:
Part 1: Fundamentals of PREMO
Contains a motivational overview of PREMO giving its scope, justification, and an ex-
planation of key concepts, describes the Overall architecture of PREMO, and specifies
the common semantics for specifying the externally visible characteristics of PREMO
objects in an implementation-independent way.
Part 2: Foundation component
This component lists an initial set of Object types and non-Object types useful for the
construction of, presentation of, and interaction with multimedia information. Any
conforming PREMO implementation shall support these Object types.
Part 3: Multimedia Systems Services Component
Describes objects that provide an infrastructure for building multimedia computing
platforms that support interactive multimedia applications dealing with synchronized,
time-based media in a heterogeneous distributed environment.
Part 4: Modelling, Presentation, and Interaction Component
Describes objects which are needed for advanced Computer Systems using graphics,
Video, audio, or other types of presentable media enhanced by time aspects.
NOTE - Further internationally standardized components are expected to be developed
within ISO/IEC JTClKC24 and by other subcommittees.

ISO/IEC 1447%1:1998(E)
INTERNATIONAL STANDARD 0 ISO/IEC
Information technology - Computer graphics and image
processing - Presentation Environment for Multimedia Objects
(PREMO) -
Part 1: Fundamentals of PREMO
Scope
ISO/IEC 14478 specifies techniques for supporting interactive Single, and multiple media applications which recognize and em-
phasize the interrelationships among user interfaces, multimedia applications, and multimedia information interchange.
ISO/IEC 14478 defines a flexible environment to encompass modular functionality and is extensible through the creation of fu-
ture components, both within and outside of Standards committees. It supports a wide range of multimedia applications in a con-
sistent way, from simple drawings up to full motion Video, Sound, and virtual reality environments.
ISO/IEC 14478 is independent of any particular implementation language, development environment, or execution environment.
For integration into a programming environment, the Standard shall be embedded in a System dependent interface following the
particular conventions of that environment. ISO/IEC 14478 provides versatile packaging techniques beyond the capabilities of
monolithic Single-media Systems. This allows rearranging and extending functionality to satisfy requirements specific to partic-
ular application areas. ISO/IEC 14478 is developed incrementally with Parts 1 through 4 initially available. Other components
are expected to be standardized by ISO/IEC JTC 1 SC24 or other subcommittees.
ISO/IEC 14478 provides a framework within which application-defined ways of interacting with the environment tan be inte-
grated. Methods for the definition, presentation, and manipulation of both input and output objects are described. Application-
supplied structuring of objects is also allowed and tan, for example, be used as a basis for the development of toolkits for the
creation of, presentation of, and interaction with multimedia and hyper-media documents and product model data.
ISO/IEC 14478 is able to support construction, presentation, and interaction with multiple simultaneous inputs and Outputs using
multiple media. Several such activities may occur simultaneously, and the application program tan adapt its behaviour to make
best use of the capabilities of its environment.
ISO/IEC 14478 includes interfaces for external storage, retrieval and interchange of multimedia objects.
2 Normative referemces
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 valid. All Standards are subject to revision, and Parties to agree-
ments based on this part of ISO/IEC 14478 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 International Standards.
ISO/IEC 14478-2: 1998, Information technology - Computer graphics and image processing - Presentation Envirqnment for
Multimedia Objects (PREMO) - Part 2: Foundation Component.
ISOIIEC 14478-3: 1998, Information technology - Computer graphics and image processing - Presentation Environment for
Multimedia Objects (PREMO) - Part 3: Multimedia Systems Services.

0 ISO/IEC
ISOHEC 14478=1:1998(E)
ISOIIEC 14478-4: 1998, Information technology - Computer graphics an.d image processing - Presentation Environment for
Multimedia Objects (PREMO) - Part 4: Modelling, Rendering, and Unteraction Component.
Definitions
For the purposes of ISO/IEC 14478, the following definitions apply.
3.2.1 multimedia: The creation, editing, composing, and/or presentation of products consisting of any combination of nze-
3.2.1.1 multimedia Object: An Object consisting of one or more types of media that tan be presented to a user-.
transmitted. Examples
3.2.2 medium (Plural media): A means by which information is perceived, expressed, stored, or
include audio, Video, (animated) graphics, images, text.
dynamic interactive graphics: Graphits applications where the graphics varies in real-time in response to user in-
3.2.3
puts.
3.2.4 animation: Series of pictures in a time-ordered sequence to display as a Video medium. This covers all changes that
have a visual effect. It thus includes the time-varying Position, shape, colour, transparency, structure, and texture of an Object,
and changes in lighting, Camera position, orientation, and focus, and even changes of rendering techniques.
3.2.5 text: A medium encompassing a Character-based encoding only.
audio: A medium encompassing all forms of information transmitted by Sound.
3.2.6
Video: A medium encompassing a continuous series of pictures typically depicting motion or time sequenced events.
3.2.7
co-representation: A representation of information where the same information is presen ted in several different
3.2.8
ways from which the most appropriate is Chosen.
3.2.9 component: A PREMO component is a set of related Object types and non-Object types. The Object and non-Object
of a component are clustered into (component) profiles.
tY Pes
3.2.9.1 Standard component: A component that is defined in one of the Parts of ISO/IEC 14478, or a component that
has been registered by an approved registration authority, and conforming to the rules defined for components in PREMO.
3.2.9.2 non-Standard component: A component that is not a Standard component, but which obeys the rules defined
by PREMO for conforming components.
Profile: A Profile is set of related Object types and non-Object types from which objects tan be instantiated, and a
32.10
configuration specification which defines dependencies between Object types and other profiles. Profiles offer a set of Services
embodied by the operations defined on its constituent Object types.
3.2.10.1 basic Profile (of a component): A mandatory set of Object and non-Object types for a specific component
provided by all complying
which shall be implementation of a component.
3.2.11 Object: An entity that encapsulates some private state information of assoc iated operations that manip-
or data, a set
ulate the data, and possibly a thread of control so that col lectively they tan be treated as a Single unit.
type: It defines the operations
3.2.11.1 Object of objects; these operations collectively characterize the object ’s behav-
iour.
3.2.11.2 Object reference: An Object name which reliably denotes a particular Object instance. This is a non-Object.
3.2.12 state: Information encapsulated within an Object
that has to be remembered when one Operation alters the future be-
haviour of future operations.
3.2.13 identity (of objects): Objects have a unique, immutable identi ty which provides a means to denote or refer to the
i ndependent of its state or behaviour.
Object
0 ISO/IEC ISO/IEC 14478-1: 1998(E)
attribute (of objects): A pair of accessor and mutator functions, to retrieve the value of to set the value of the at-
3.2.14
tribute.
3.2.14.1 retrieve only attribute: An Object attribute where the mutator function to set the value, though conceptually
present, does not Change the value of the attribute, and raises an exception.
3.2.15 signature (of operations): An Operation3 signature consists of a list of Parameter types, and a list of result types.
3.2.16 interface (of objects): The set of Operation signatures defined for a type.
non-Object types: Things that are not objects, e.g., integers, real numbers.
3.2.17
Operation: Describes an action that tan be applied to an Object, using Parameters.
3.2.18
3.2.18.1 Operation invocation: Activation of an object ’s action, by describing its Parameters, possibly causing results to
be returned.
3.2.18.2 Operation request: Synonym for Operation invocation.
3.2.18.3 Operation dispatching: The selection process which selects a specific Operation implementation for execution.
tation te@ace Supersedes the im-
3.2.18.4 Operation overloading: The implernen of an Operation defined for a derived in
base interface. This effect is called Operation overloading.
plementation of the Same Operation defined for a
3.2.19 client: (of another Object) An Object issuing an Operation request.
3.2.20 exception: Information returned if an error condition has occurred during the execution of a request of an Operation.
3.2.21 controlling Parameter: Special Parameter conceptually present for all operations, used to control the way opera-
Gons are dispatched. It refers to the Object type on which the Operation is defined.
determined to be ac-
3.2.22 subtyping: A relation ship bet ween types. It defines the rules by which objects of one type are
another
ceptable in contexts expecting
tY Pe.
3.2.23 subtype: A type S is a subtype of another type T if any Object of type S tan be used in any context that expects an
Object of type T.
3.2.23.1 immediate subtype: A type S is an immediate subtype of another type T, if T is the immediate Supertype of S.
3.2.24 Supertype: A type T is a Supertype of S, if S is a subtype of T.
Supertype; they are to as multiple
3.2.24. 1 multiple Supertype: An Object type tan have more one referred super-
types.
3.2.24.2 immediate Supertype: A type T is an immediate Supertype of type S, if it is a Supertype of S, and there is no type
Q such that Q is a Supertype of S and T is a Supertype of Q.
3.2.25 direct instance: An Object is a direct instance of a type T, if it is an instance of Tand not an instance of any subtype
of T.
3.2.26 immediate type: The type of the direct instance of an Object instance.
The set of all supertypes of a type (including the recursively defined supertypes) plus the
3.2.27 type graph (of a type):
type itself.
inheritance : A notational mech anism for defining Operation reuse. It is a relationship on interfaces.
3.2.28
3.2.28.1 multiple inheritance: A notational mechanism for defining Operation reuse on multiple base interfaces.
3.2.28.2 Single inheritance: As opposed to multiple inheritance; denotes an interface having only one base interface.
3.2.29 derived interface: If the interface P inherits from Q, P may also be referred to as a derived interface.
base interface: If the interface P inherits from (3, Q is a base interface (of P).
3.2.30
3.2.31 abstract Object type: Non-instantiable Object type.

0 ISO/IEC
ISO/IEC 14478-1: 1998(E)
3.2.32 Operation request semantics: A finer control an Object has to Service an Operation request.
3.2.32.1 Operation receptor: A holder conceptually assigned to each ope.ration in which Operation requests are placed.
3.2.32.2 Operation receptor mode: An immutable characteristics of an Operation receptor.
synchronous Operation receptor mode: One of the three possible modes of an Operation receptor; callers
3.32.2.1
are suspended on Operation requests.
asynchronous Operation receptor mode: One of the three possible modes of an Operation receptor; call-
3.32.2.2
ers are not suspended on Operation requests, and the request ’s arguments are stored.
ne of the three possible modes of an Operation receptor; callers are
3.32.2.3 sampled Operation receptor mode: 0
requests argument is stored.
not suspended on Operation requests, and only one
Operation which tan be invoked from within the Object instance only; other Object instanc-
3.2.33 protected Operation: An
es cannot request this Operation.
3.2.34 life cycle (of objects and references): The mechanisms whereby objects and Object references are created and de-
stroyed.
3.2.34.1 life cycle facilities: The boundary between PREMO and its implementation environment, providing life cycle
related Services.
3.2.34.2 create facility: Facility to create objects possibly using initialization variables.
3.2.34.3 copy facility: Facility to create objects as copies of already existing objects.
3.34.3.1 shallow copy: Version of the copy facility attribute values are set in the newly created Object using
the values of the attributes in the orig inal Object.
3.34.3.2 deep copy: Version of the copy facility when attribute values are set in the newly created Object using the
values of the attributes in the original Object except for Object references; in the case of Object references, the referred
objects are (deep) copied, and the new reference values are used to set the attributes.
3.2.34.4 cast facility: Facility to create an Object reference to an already existing Object, referring to a different immediate
tY Pe.
3.2.34.5 destroyReference facility: Facility to destruct an Object reference.
3.2.34.6 destroyobject facility: Facility to destruct an Object instance.
3.2.35 type Schema: A notational convention used to describe Object types (see clause A.3).
3.2.36 Operation Schema: A notational convention used to describe an Operation within a type Schema.
3.2.37 component Schema: A notational convention to describe components (see clause A.7).
Profile Schema: A notational convention to describe profiles within a component Schema (see clause A.7).
3.2.38
3.2.39 generic type (Schema): A notational convention used to describe a family of PREMO based on the general
types,
notational conventions of type Schema (see clause B).
3.2.40 formal types: Symbols used in generic type Schemas to denote non-specified Object or non-Object types.
3.2.41 actualization: A notational convention whereby generic type Schema are used to define PREMO Object types
through replacing formal types by PREMO Object or non-Object types.
The following alphabetical list gives the subclause of each definition.
abstract Object type 3.2.31
actualization 3.2.41
animation 3.2.4
3.32.2.2
asynchronous Operation receptor mode
0 ISO/IEC
ISO/IEC 14478-1: 1998(E)
attribute (of objects) 3.2.14
audio
3.2.6
base interface 3.2.30
basic Profile (of a component)
3.2.10.1
cast facility
3.2.34.4
client
3.2.19
co-representation
3.2.8
component
3.2.9
component Schema
3.2.37
controlling Parameter
3.2.21
copy facility 3.2.34.3
create facility 3.2.34.2
deep copy 3.34.3.2
derived interface 3.2.29
destroyobject facility
3.2.34.6
destroyReference facility
3.2.34.5
direct instance
3.2.25
dynamic interactive graphics
3.2.3
exception 3.2.20
formal types 3.2.40
generic type (Schema) 3.2.39
identity (of objects)
3.2.13
immediate subtype
3.2.23.1
immediate Supertype
3.2.24.2
immediate type
3.2.26
inheritance
3.2.28
interface (of objects)
3.2.16
life cycle (of objects and references)
3.2.34
life cycle facilities
3.2.34.1
medium (Plural media) 3.2.2
multimedia 3.2.1
multimedia Object
3.2.1.1
multiple inheritance
3.2.28.1
multiple Supertype
3.2.24.1
non-Object types 3.2.17
non-Standard component 3.2.9.2
Object 3.2.11
Object reference 3.2.11.2
Object type
3.2.11.1
Operation
3.2.18
Operation dispatching
3.2.18.3
Operation invocation 3.2.18.1
Operation overloading 3.2.18.4
Operation receptor
3.2.32.1
Operation receptor mode 3.2.32.2
Operation request
3.2.18.2
Operation request semantics
3.2.32
0 ISO/IEC
ISO/IEC 14478=1:1998(E)
3.2.36
Operation Schema
3.2.10
Profile
3.2.38
Profile Schema
3.2.33
protected Operation
3.2.14.1
retrieve only attribute
3.32.2.3
sampled Operation receptor mode
3.34.3.1
shallow copy
3.2.15
signature (of operations)
3.2.28.2
Single inheritance
3.2.9.1
Standard component
3.2.12
state
3.2.23
subtype
3.2.22
subtyping
3.2.24
Supertype
3.32.2.1
synchronous Operation receptor mode
3.2.5
text
3.2.27
type graph (of a type)
3.2.35
type schema
3.2.7
Video
4 Symbols and abbreviations
Computer-Aided Design / Computer-Aided Manufacturing.
CADKAM:
International Electrotechnical Commission.
IEC:
International Standard.
1s:
International Organization for Standardization.
ISO:
Joint Technical Committee.
JTC:
Presentation Environments for Multimedia Objects.
PREMO:
Two and a half dimensional.
2SD:
Two-dimensional.
2D:
Three-dimensional.
3D:
5 Conformance
A component is defined in PREMO to be a set of related Object types and non-Object types and a set of Profile specifications. A
component is considered to offer a set of Services, embodied by the operations on the objects, and may also depend on Services
provided by other components.
PREMO defines conformance with respect to components as follows:
a) PREMO specifies conformance rules that shall apply for any definition of a conforming component;
b) PREMO specifies conformance rules that shall apply for any implementation of a conforming component;
c) PREMO specifies conformance rules that shall apply for any implementation of a conforming PREMO System.

0 ISO/IEC ISO/IEC 14478=1:1998(E)
A conforming component shall be defined according to the rules described in clause 9. It may also include additional require-
ments that shall apply to implernentations of the component.
An implementation of a conforming component shall provide the mandatory set of functionality designated as a basic Profile for
that component, realize the configuration specification defined for that component, and in addition provide for any other imple-
mentation requirements that are given as part of the component ’s definition.
A Standard component is a conforming com ponent defined in one of the Parts of PREMO or one that has been registered by an
approved registration authority.
An implementation of a conforming PREMO System (i.e., a System implemented using PREMO components) shall obey the con-
formante requirements of each of the components from which it is constituted.
6 Requirements for PREMO
61 l Introduction
Technology has evolved to the Point that digital media has become an inherent part of most applications. In addition, many ap-
plications use multiple presentation media simultaneously. This combination has resulted in a large number of diverse require-
ments. ISO/IEC 14478 is intended to address the presentation requirements of such diverse application areas as:
a) medical Systems,
b) education/training,
c) virtual reality,
d) geographic information Systems,
e) digital publications,
f) scientific visualization and data exploration,
g) entertainment,
h) realtime command control Systems, and
simulation;
i>
and such presentation and interaction techniques as:
j) animation,
k) simultaneous use of multiple media,
1) multimodal user interfaces,
m) realistic rendering (including various dimensionalities, such 2D, 2.5D, 3D, and incorporating various media, such as
Video, Sound, and other non-visual data).
ISO/IEC 14478 provides a common underlying functional nucleus to support these application areas and presentation techniques,
as weh as future areas and techniques. PREMO also enables the use of interaction techniques appropriate for specific applica-
tions, such as those listed above.
PREMO provides a generic framework, into which various organizations or applications may place their specialised objects with
specific behaviour, thereby enabling interoperability. In this sense, PREMO is intended to serve as middleware, coordinating
multimedia components.
0 ISO/IEC
ISO/IEC 14478=1:1998(E)
62 . Extensibility
ISO/IEC 14478 is extensible in that it makes provisions for extending the functionality specified in the Standard via a number of
standardized mechanisms. In particular, additional components may be developed which respond to the needs of specific appli-
cation areas. See also clause B in ISO/IEC 14478-2 for further details on the way PREMO objects may be extended.
Many aspects of ISO/IEC 14478 are extensible by an ISO-administered registration mechanism, so that a uniform description of
the extension is available to all implernentations.
63 . Configurability
The need for configurability arises because different application areas have different demands on the task of presenting their data.
PREMO embodies a configurable System design which offers a foundation from which specific requirements for Object support
and interrelationships tan be realized. This configurable System design is based on the concepts of components and profiles (see
clause 7.3.4 and clause 9). In a configurable System, profiles tan be Chosen according to the special needs of particular applica-
tions. The advantages of a configurable System design are:
a) Applications do not reference the whole System but only the specific component profiles they require. For example, an
application might need only an audio or Video Profile.
b) When introducing new techniques, e.g., shading methods within a graphics System, or a special purpose graphics data
storage, there is no need to implement a completely new graphics System for the realization of these new approaches. They
tan be integrated as new Object types that fit within the existing foundation.
64 . Incremental, separable development
ISOIIEC 14478 is described and structured in such a way that it tan be developed incrementally. The Chosen architecture provides
a foundation for a n evolvable fa .mily of Standards.
Simplicity
65 .
Aspects, such as portability and maintenance, are greatly enhanced by keeping underlying concepts simple. Simplicity means that
PREMO is based on a general architecture under which various sets of objects may be utilized. Objects are defined in terms of
their externally visible behaviour, thereby hiding implementation details. Hierarchical structuring of and within objects is possi-
ble, thereby allowing more complex entities to be assembled from simpler Parts.
66 . Ease of use
PREMO is easy to use for at least the following classes:
a) end users (individuals or groups), who work with information processing applications based on PREMO;
b) programmers, who use PREMO components to build applications;
sell, and Service implernentations of PREMO;
vendors, who develop, and
C>
who control and manage multimedia Systems.
System administrators,
d)
ISO/IEC 14478-1: 1998(E)
0 ISO/IEC
67 . Other influences
6.7.1 Application development environment
PREMO takes advantage of an Object-oriented design philosophy. This aspect is differentiated from different kinds of language
bindings addressed below. Thinking in terms of objects leads to a natura1 description of the functionality of distributed multime-
dia Systems entailingr
a ) uniform mechanism to access passive or active entities;
of the attributes of objects as inherent information;
b) the treatment, description, assignment, and modification
c) a clear understanding concerning the concurrent existente of objects that the user may freely select and modify; and
d) the definition of different objects with equivalent behaviour as instances of a common
tY Pe.
Many benefits of the Object-oriented approach taken by PREMO tan be realized without requiring that applications be imple-
mented in Object-oriented or Object-based languages. PREMO tan be bound to both Object-oriented and non Object-oriented
languages. However, the functionality of PREMO is defined so that the advantages of Object-oriented environments - especially
subtyping and inheritance and the ability to define mutual communication between application objects and multimedia objects
- tan be used. Subtyping and inheritance offer mechanisms to extend PREMO functionality and to adapt it to specific areas of
applications, whereas mutual communication supports a stronger symmetry between input and output. Notwithstanding the
above, one main goal for describing the functionality is that it is not limited to only Object-oriented environments.
6.7.2 Execution environment
PREMO allows applications to take advantage of distributed environments. It allows distribution of func tionalities across multi-
ple processors. Where and when applicable, PREMO is compatible with, or is defined in terms of, other international Standards.
68 . Functionality
Introduction
6.8.1
PREMO supports the construction of, presentation of, and interaction with objects consisting of still Computer graphics, moving
Computer graphics (animation), audio, text, still images, moving images (including Video), images coming from imaging opera-
tions, and any other media type or combination of media types that tan be presented.
6.8.2 Computer graphics
The objective of PREMO is to consider the evolving needs of the Computer graphics and applications communities. Increasingly
this means catering to the integration of Computer graphics in multimedia applications. The underlying concepts and functionality
of PREMO provide a visible route which the community tan follow to take advantage of ISO/IEC 14478. This shall be accom-
plished by providing simple yet extensible functionality in a well-defined manner.
6.8.3 User interfaces
PREMO goes beyond the presentation and interaction requirements of simple oraphical user interfaces by supporting the inte-
b
grated use of multiple media, for example, through simultaneous presentations.
6.8.4 Dynamit interactive graphics
PREMO provides for real-time control and presentation of dynamic interactive Computer graphics applications, where the graph-
ics varies in real-time in response to external inputs. It allows an application to integrate dynamic Computer graphics with other
media.
ISOLEC 14478=1:1998(E) 0 ISO/IEC
6.8.5 Animation
PREMO provides for real-time control of media presentation, including the presentation of time-varying information, e.g., slide
Shows, smoothly moving objects. It allows an application to integrate animation with other media. PREMO provides mechanisms
that tan be used to create animated audio-visual applications.
6.8.6 Audio
presentation. It allows an application to
PREMO provides for real-time control of both analogue and digital audio information
integrate
audio with other media.
6.8.7
Video
PREMO provides for real-time control of the presentation of both analogue and digital Video information. This includes both
Single frame and time-varying Video data. It allows an application to integrate Video with other media.
6.8.8 Other and future media
PREMO supports media besides the ones listed in this clause. PREMO is extensible to support any media type or combination
of media types that tan be presented. Examples of such media include haptic and thermal sensory presentations.
6.8.9 Co-representations
PREMO supports co-representations. That is, the same information tan be presented in several different ways from which the
most appropriate is Chosen. For example, PREMO allows a modeller to choose the most appropriate renderer from among those
available. It allows information to be represented in a variety of media - for example audio and Video - from which the most
suitable tan be Chosen based on the application ’s needs and the capabilities of available devices.
6.8.10 Cooperating applications
PREMO supports real-time exchange among applications cooperating in interaction with the same Scene. This includes both co-
Operation between different media and the exchange of Single media and multimedia objects.
Architecture of PREMO
71 . Introduction
PREMO tan be conceptually described in at least three different ways. These three architectural perspectives each have their own
way of describing the Parts of PREMO and their interrelations.
The three architectural perspectives are:
a) the Standards perspective, which explains how PREMO is organized as a multi-part Standard.
b) the functional perspective, which introduces the organization of PREMO as a collection of components, profiles, and
Object and non-Object types. It also includes types related to non-presentation functionalities. Emerging ISO and other Object
technology Standards - such as standardized Object description techniques, Object request brokers, traders, and Object serv-
ices - should be influenced by PREMO requirements and provide capabilities that PREMO tan utilize.
c) the System perspective, which explains what Systems may result from PREMO implernentations and how different
PREMO implernentations shall interoperate. It explains what aspects of an environment should be brought under control of
PREMO as opposed to transparent aspects (e.g., distribution). This architecture also allows precise formulation of portability
and interoperability requirements for PREMO implernentations.
0 ISO/IEC ISO/IEC 1447%1:1998(E)
72 . The Standards perspective
PREMO envisages a broad scope of functionality which cannot be covered by a Single activity. Therefore, PREMO has been
designed as a multipart Standard. The first part (ISO/IEC 14478-1) explains key concepts, describes the Overall architecture of
PREMO, and specifies the common semantics for specifying the externally visible characteristics of PREMO objects in an im-
plementation-independent way. The second part (ISO/IEC 14478-2) defines those objects that any conforming PREMO imple-
mentation shall support. The third part (ISO/IEC 14478-3) defines a Multimedia Systems Services component which provides an
infrastructure for building computing platforms that support interactive multimedia applications dealing with synchronized,
time-based media in a heterogeneous distributed environment. The fourth part (ISOLIEC 14478-4) defines a Modelling, Presen-
tation, and Interaction component which is targeted at providing paradigm independent support for high-level modelling and
presentation, enhanced by time control and interaction, and using various media.
Further Parts are anticipated that will be appropriate for specific application areas. For example, a PREMO-based mapping from
existing Computer graphics Standards will allow many existing applications to be integrated into multimedia presentations. Also,
the development of toolkits and highly interactive and portable authoring tools for the generation and presentation of multimedia
documents could be defined based on functionality specified by other international Standards committees.
73 . The functional perspective
Introduction
7.3.1
The functional perspective groups presentation and interaction functionality in terms familiar to an application programmer
(e.g., aspects of time , geometry, etc.) and functionality necessary to achieve certain effects, where the programmer is possibly
unaware of the underlying techniques used to achieve these effects (e.g., forms of anti-aliasing, colour representations, structur-
ing of presentation data).
The functional architecture is restricted to a conceptual description of the functionality, leaving further detail or realization to the
foundation and non-foundation components. It identifies the functional areas common to all media components, but possibly hav-
ing different realizations in each environment.
The functional architecture explains the nature of the rules for components and profiles such that they tan be combined (config-
ured) and linked to other standardized or external non-Standard components. The selection of components to assemble the func-
tionality needed for a given application and in Order to be able to run on a target platform is based on criteria such as:
- how components tan interface to one another,
- how new components may reuse Parts of older components, and
- how components tan be realized on the corresponding part of the implementation platform.
7.3.2 Description techniques
PREMO functionality is described in terms of Object behaviour. Esch PREMO Object is specified by giving:
a) a definition of its interface;
b) a description of the object ’s behaviour. Such a description specifies the object ’s visible behaviour, the effects of opera-
tions on the object ’s internal state, the output Parameters of each Operation request it is capable of receiving, and the input
Parameters of these requests?
The notational conventions used for Object specifications are described in clause A.3 and Annex B.
using formal description techniques, are being developed
IJ Descriptions of the objects’ behaviour, separately and may be published as accompanying technical
reports.
ISO/IEC 14478=1:1998(E) 0 ISOIIEC
7.3.3
The Object model
An Object-oriented description technique is used to specify PREMO functionality. The Object-oriented terminology and formal-
ism constitute an Object model in which objects and Object types are composed and made to interact. The manner in which PRE-
MO is described is independent of both the techniques used to construct PREMO implernentations and the languages to which
those implernentations may be bound. PREMO tan be bound to, and implemented in, both Object-oriented and non object-ori-
ented programming languages. The Object model is described in clause 8.
7.3.4 Components
A component is a collection of profiles where specific profiles are defined to offer particular sets of functionality in the form of
Object and non-Object types. Esch Profile is defined in terms of its dependencies on other profiles (either internal, i.e., depend-
encies on profiles belonging to the same component, or external, i.e., dependencies on profiles belonging to another component)
and the Object and non-object types it provides for other components.
The exact rules for components and profiles are given in clause 9 with the notational conventions described in clause A.7 of this
part. These rules ferm the basis for the properties of configuration, customization, extensibility, and interoperability.
74 . The System perspective
7.4.1 Configuring PREMO-based applications
The functionality of PREMO is realized by a set of Object types. The PREMO architecture provides mecha
...