Design Guide for Multimedia
Design Guide
for Multimedia
Table of Contents
Who is this document intended for?4
Usability Activities in the design cycle5
1.Multimedia products6
1.1Are multimedia products similar to books?6
1.2What are multimedia products?7
1.3What is the specific purpose of multimedia design guidance?7
1.4What kind of knowledge and know-how is required for multimedia design8
decisions?
1.5Can design of multimedia products be principle-driven?8
1.6What are the elements of multimedia design?8
2.Interfaces to multimedia products11
2.1Is there a typical configuration of equipment used for multimedia products?11
2.2What types of multimedia interfaces will be covered by this guide?11
3.Use and user of multimedia products12
3.1Who are the typical users of multimedia products?12
3.2What are the typical motivations for people to use a multimedia product?12
3.3How can multimedia products be tailored to specific tasks and users?12
3.4Direct versus indirect access12
4.General principles for multimedia design14
4.1Choice of media14
4.2Principles for multimedia14
4.3Usability Measures for multimedia15
4.4Matching user needs to media16
5.Use and design of manual input devices for multimedia 17
5.1Keyboards17
5.2Soft keys17
5.3Mouse18
5.4Trackball or Rollerball18
5.5Touch Screens18
5.6Touch Pad19
5.7Graphics Tablets19
5.8Joysticks19
5.9Light pens20
5.10Input Device Summary Table20
6.Use and design of visual output media for multimedia21
6.1Introduction21
6.2Text22
6.3Colour23
6.4Charts and gauges25
6.5Photographs or images26
6.6Graphics27
6.7Icons27
6.8Video28
6.9Animation28
7.Use and design of acoustic user interfaces30
7.1Introduction30
7.2Usability goals for acoustic user interfaces30
7.3Different uses of acoustic user interfaces30
7.4Global design issues for acoustic user interfaces31
7.5Speech input32
7.6Speech output33
7.7Music34
7.8Sounds34
8.Multimedia integration37
8.1Introduction37
8.2Combining audio with visual information37
8.3Visibility of the speaker during speech output37
8.4Synchronisation38
9.Navigation, orientation and access39
9.1Introduction39
9.2Metaphors39
9.3Navigation structures40
10.References42
11.General reading on multimedia design44
Who is this document intended for?
This document is intended for the person or group of persons who is charged with becoming the usability representative(s) in their organisation or project. Such people may be new to usability or may already have a sound knowledge of the principles of usability engineering, and may have used some tools successfully in the past. They seek to find the best of the current tools available to introduce usability engineering into their organisation.
This is a guide to the "Contextual design of multimedia products". Contextual design means: paying attention to the entire context of use of a product, including social-cultural norms and habits of the user community, task structure, user characteristics, as well as technological constraints, especially affordable input and output modes. It also implies de-emphasising the technical aspects of multimedia systems while focusing on human factors, aesthetic and satisfaction aspects, as well as the social dimensions of those systems in use by actual users.
The focus of interest here is to describe the main principles and features which are essential for successful multimedia products without the professional jargon used by software developers or multimedia technical specialists. The guide focuses on design requirements and design features of the end products of multimedia development efforts, e.g. kiosk systems, multimedia tools for instruction, and professional information systems offering multimedia services.
By offering context related advice, the audience for this guide includes product managers, technical managers and usability specialists of multimedia delivery systems. It is not intended particularly for professional system developers who build and integrate multimedia hardware and/or software, as they will require much more specific advice.
The document does not, for example, talk about the features of a full-blown hardware and software environment for the creation of multimedia products, i.e. a multimedia production studio. Neither does it say much about the organisation of professional multimedia application teams which require completely new kinds of interdisciplinary co-operation and knowledge-sharing compared to the ones in traditional computer application development. For those interested in both of these topics, there are already reports and handbooks describing hands-on experiences with developing such systems.
This document has been developed as part of the Telematics Information Engineering INUSE project (European Usability Support Centres). A human-centred iterative design for multimedia systems also depends on activities such as user-based requirements and rapid prototyping. Guidance from the RESPECT project is available for this aspect of the development activity.
The reader is referred to the web homepages of both the INUSE and RESPECT projects for more information, including contact addresses of local service centres:
and the project manager of both projects, Dr Nigel Bevan, may be contacted by email at:
Usability Activities in the design cycle
The above diagram is a representation of the activities that usability professionals carry out as part of software development. In the centre of the diagram are three boxes corresponding to the elements of user-based analysis, interface design, and testing and evaluation. Each of these three activities has always been important in the development of software systems, however, for highly interactive systems the correct management of these activities is crucial.
Around these activities is a frame of ‘interface’ management: that is, the interface between the user-centred activities in the inner boxes and other elements of the software design process. Some of these elements are listed on the right hand side of the interface frame. It is up to the usability expert(s) in the organisation to provide this interface in an effective manner, otherwise usability activities will not have any impact on the rest of the product development.
At the foot of the diagram is a component related to the management of the user-centred activities, to indicate that these activities should be placed within a management perspective: there should be clearly established usability goals alongside the technical system goals. All the activities above management in the diagram should be integrated and ‘orchestrated’ by the management function. Usability management also connects with other aspects of product development management, and this is indicated by the continuations of the management box to its right and left. This serves as a reminder that one of the ways in which to ensure that the results from usability activities contribute most effectively to overall product development is to make usability management part of the overall system development plan.
The purpose of the INUSE project and all the other contributors to the European Usability Support Centres network is to provide those personnel charged with the usability functions in their organisation with tools and methods to fulfil the functions within the central three boxes and usability activity management. If the usability personnel do not have good tools and reliable methods, they must rely more heavily on their ability to interface with the rest of the organisation and thus on their usability craft skills to carry out informal usability activities.
Various documents produced by INUSE and other contributors to the European Usability Support Centres network give best-practice guidance on the way the different elements corresponding to the entities in the diagram should be implemented. The current document focuses on the activity of designing for Multimedia Systems.
1.MULTIMEDIA PRODUCTS
1.1Are multimedia products similar to books?
Multimedia may be defined as the use of different input devices and different media, both time dependent (sound, music, voice, video) and time independent (graphics, text) in a system or service (Clarke, 1992). A multimedia system or service may therefore include a combination of text, still images, graphics, video, animation, sound and speech as output media. To interact with these elements, the user may use a mouse, tracker ball, joystick, touchscreen, pen, stylus, keyboard or speech for input.
There is a view on multimedia which starts from the concept of a book or more generally a document containing text and graphics (including data and tables as intermediate forms). Adding audio and/or video to an electronic document will make it a multimedia document; adding so-called links or hyperlinks between different locations in the document or in another document will create a hyper document; adding both features at the same time results in what has been dubbed hypermedia documents. The terms “bookness” or “booklike” have therefore been introduced to refer to the quality of such systems.
However, this is a rather simplistic and too technical a view, which does not highlight the tremendous consequences which this generalised concept of a document has on the way normal users will interact with a multimedia system. In fact, from the user‘s point of view, it is irrelevant that multimedia is a natural evolution from plain paper documents, e.g. books, to dynamic digital information systems, e.g. point of sale systems. For users, the look and feel will be very different, and they will have to learn new habits and expectations when working with such products, even if many of them are designed according to the “walk-up-and-use” paradigm.
Multimedia products may exhibit many of the typical features mentioned above, i.e. the possibility to jump from one location in an information space to any (or almost any) other location and to find information of different types like text, audio or video. However, these features alone are not enough to define the emerging category of multimedia products or to justify its use.
The strength of multimedia lies in the integration of different media. This can lead to an increase in the comprehension of information, as people tend to learn more readily when exposed to information in several modes, such as a photo of a famous painting together with a textual description. However the success of multimedia depends more on the chosen combination of media and its implementation, rather than simply on the provision of a rich set of media. For example, a user may become annoyed if pictures are always accompanied by audio or if the picture quality is good but the audio is poor.
The suitability of different media for presenting certain information is determined by various factors e.g. the nature of the application, likely frequency of use, environmental conditions etc. Good design will take these factors into account. For example the user will often require the ability to control the media such as a teacher turning down the volume of sound on a classroom computer to avoid disturbing children performing other activities.
The main sections in this document discuss user issues for different media. This is followed by some comments on mixing media.
1.2What are multimedia products?
Multimedia systems can currently be classed as consumer or educational products. They differ from normal applications in the office and in industry e.g. plain word and data processing systems, in that they are mainly intended for domain-specific information presentation by means of simple and familiar interactions with the user: they are information or knowledge assistants. However, as multimedia products develop and become a working tool in professional environments, this will change profoundly, e.g. multimedia electronic mail used by office staff or multimedia patient records used by hospital staff.
The scope or purpose of such consumer products may be highly diverse: they may be used for customer information (e.g. in a hotel or in a shop) as an end in itself; for preliminary information gathering in order to enable the user to start another activity or task; as a learning device (e.g. in school and other teaching/training organisation); as an exploratory device; or as a cultural or community information system (e.g. in a museum, town-hall).
Thus, multimedia products are inherently special-purpose applications. The advantages of special purpose systems are enormous: they can be optimally tailored to the task and to the user, both for low level design e.g., choosing the most appropriate kind of input or output devices, optimising speed and reliability — and for high level design e.g., task specific interaction techniques, intelligent user support, highly specific error prevention and error recovery schemes, etc.
Genuine multimedia products also support an "analogue" means of understanding and working with the "digital" world of computers. Adding time-dependent media like audio and video or gestures and handwriting to the static world of numbers, text and graphics makes information storage and retrieval much more intuitive and understandable for the average user.
1.3What is the specific purpose of multimedia design guidance?
Effective multimedia design means adopting a systematic and comprehensive approach to analysing the context of use: i.e. looking at and modelling all the components and aspects involved. This will involve user, task and environmental characteristics. Good multimedia product design pre-supposes attention to a whole series of critical components: sufficiently powerful hardware, highly reliable software, excellent human factors, thorough product design, etc.
The intended functions of a multimedia product, e.g. a kiosk system for a warehouse, might be realised in many alternative ways. Important factors to consider when assessing various designs will include;
•Effectiveness - giving the user what he or she needs
•Efficiency - not requiring too much effort from the user
•Satisfaction - invoking positive feelings and lasting acceptance by the user.
1.4What kind of knowledge and know-how is required for multimedia design decisions?
The technical complexity of multimedia products almost always enforces highly specialised solutions which can only partially be covered by general ergonomic standards relating to product appearance and product development. In particular, multimedia product design supposes the following sources of knowledge:
•A working knowledge of the social and organisational context and constraints on the product, i.e. what is the environment in which the product will be used? What are the information access points? Who are the stakeholders, including owners, producers and consumers, of the final system?
•A working knowledge of the expected users of the multimedia product: users normally are very diverse with respect to their level of education, and their level of acquaintance with, and acceptance of, 'high-tech' consumer products like remote control handsets for VCRs, mobile phones and electronic banking. There are of course likely to be differences for certain groups with special needs, such as very young users, older users, people with disabilities, etc.
•A working knowledge of the range and types of intended tasks or usage of the multimedia products, i.e. which human activities or social processes will be supported by the product and what are the intended benefits? Will the product be used for clerical tasks, learning tasks, or entertainment?
•A working knowledge of the types and range of media or coding systems available. This will include the types of acceptable input (e.g. numerical, textual, handwriting, speaking, gesture and movement), the types of acceptable output (e.g. textual, graphical, acoustic, tactile), as well as mixed forms (e.g. screens used both for data display and input selection).
The Usability Context Analysis guide (Bevan et al, 1996) presents a framework for gathering this information.
1.5Can design of multimedia products be principle-driven?
Principles of design, like those in part 10 of the international standard ISO 9241, and specific design recommendations as in parts 12 to 17 of the same standard can be very useful for designers of a particular interactive product. This standard for ergonomic workplace design proposes general human factors principles as well as detailed design options for the most conventional interface objects and dialogue forms such as menus, commands, pointing, form handling, etc.
The standard does not, however, specify the typical development processes or decision procedures by which a single design can be arrived at. It only touches upon those concepts which are fundamental to multimedia products like navigation structures, information linking, non-graphical input and output, task design for people with special needs, etc.
Both general and specific standards have limitations in practice. General principles of design are really high-level abstractions which have to be rediscovered during actual design. On the other hand, specific guidelines will have many exceptions to their use. Multimedia design will rather be driven by the needs of particular users, tasks or more general contexts of use which normally include many different stake holders. Therefore design support has to be phrased in terms of examples or scenarios for actual use, not by way of principles. Of course, principles may be derived afterwards from that detailed information. Finally, the guidance given by a design support system should be as independent as possible from the particular hardware and software platform in order to be widely applicable.
1.6What are the elements of the multimedia design?
Based upon the preceding considerations, the following elements of a multimedia system that need to be designed:
•Content: Specify the information needs and interaction requirements of the users in the different tasks, i.e. What kind and level of detail of information do the users want to receive? How do they want to select and access that information? This amounts in some form to task content and structure analysis, where the "task" includes non-job-related activities, such as browsing a system for leisure purposes.
•Structure: Specify the structure between different pieces or chunks of information and how the user might gain access to this information. For example, a business graphic might illustrate the data in a table or text. This is especially important in the case of hyper-media, which has linked structures with multiple associations between all kinds of data.
•Access: Specify the information navigation and access techniques, i.e. How will the user know when related information is available and how to access it? Do users always know how to locate themselves in the information space and to find the way back to where they came from? Is the user allowed to make new connections between arbitrary or selected pieces of information?
•Style: Specify the way each component of information will be presented to the user. In which modality will the information be presented (textually, verbally, graphically, by animation, by audio or video sequences, still images, etc.)? Will it be shown only once and disappear, or remain for closer inspection or repeated presentation? Can it be interrupted or hidden? Can the user switch between different presentation modes depending upon preference or circumstance?
Figure 1, below, illustrates the different design elements: