Multimedia Systems
Instructor: Bajuna Salehe
Email: bajunar@yahoo.com
Web:
http://www.ifm.ac.tz/staff/bajuna/courses
Design Considerations of
Multimedia Systems
Main Agenda
• Human Computer Interaction (HCI)
• Overview of Software Design Methods
• General Methods of Multimedia System
Design
Human Computer Interaction (HCI)
• HCI affects design decisions that are
expected to be made during the
development of Multimedia Systems.
• The major focus of HCI is on ‘User
Interface’
– The design of User Interface must well take
into account what we call ‘user friendliness’ or
‘Usability’.
Human Computer Interaction (HCI)
• The following usability attributes should be
considered in designing HCI:
– Learnability – systems should be easy to use
so that the user could be immediately be able
to work with it.
– Efficiency – System should be efficient to use
to achieve high productivity once learnt well.
Human Computer Interaction (HCI)
– Memorability – The system should be easy to
remember.
– Errors – The system should have low error
rate.
– Satisfaction – The system should be pleasant
to use to satisfy user.
• Just get a quick review of HCI to have
more recipes in Multimedia System
Design.
Overview of Software Design
Methods
• The design of multimedia systems follow
the same underlying process of software
engineering (SE).
• Therefore the designer of multimedia
systems should be aware of general
methods of SE.
– From Waterfall Model to Object Oriented
System Design.
User Interface Design Cycle
• In designing user interface there are three
stages:
– Design stage – Collecting information about
users’ needs (Requirement analysis).
– Implementation/Prototyping Stage – A
prototype system is implemented based on
the information gathered.
– Evaluation Stage – Evaluate the prototype,
through users’ feedback before the final
system is developed.
Designing Multimedia Systems
• Generally the design process of
multimedia systems follows the following
steps:
– Identifying the requirements of the systems.
– Identifying the design issues.
– Implementation.
– Testing and evaluation.
Designing Multimedia Systems
• These steps are not well enough to get the
project start well in designing multimedia
systems.
• A multimedia systems requires detailed
and well-planned approach toward media
integration issues.
– Handling mix of various medium such as
audio, animation, text and graphics is the big
challenge to the designer.
System Requirement
• This stage is comparable to the
‘requirement specification’. The stage has
the following key functions:
– Provide system definition which outlines the
aims and the objectives of the system.
– To clarify the potential users of the system.
– To critically evaluate the required hardware as
well as the available software platforms and
authoring tools.
Design Consideration
• Draw up clear guidelines about the design
details.
• This stage aims at:
– Design metaphor: Select a ‘real world mental
model’ to be used as the key interface design
solution for the system (i.e movie, a book, a
game, … etc)
Design Consideration
– Information types and formats: Define
information that needs to be integrated into
the system, i.e. text, graphics, sound, video,
and animation.
– Navigational structures: To articulate a clear
navigational strategy, including the link
structure.
– System controls: To clarify the types and
features of controls and tools needed for the
systems.
• May include sound, video and animation controls.
Important notes in Design of MS
• Furthermore due to their complexity in
nature multimedia systems design process
should start by taking into consideration
their unique characteristics.
– The huge amount of data that needs to be
processed and transmitted in a continuous
manner, and the timing constraints that need
to be satisfied in order to have an
informational message meaningful to the enduser.
Important notes in Design of MS
• Another important characteristic is the
Quality of Service (QoS) which embraces
all the non-functional properties of a
system (e.g. power consumption, cost,
etc.).
• In multimedia systems, QoS requirements
vary considerably from one media type to
another.
– E.g the video streams require consistently
high throughput (high bandwith), but can
tolerate reasonable packet errors.
Implementation
• Once the design features are defined, the
implementation phase of the system
begins using multimedia-authoring tools.
The implementation stage consists of:
– Creating a prototype of the system.
– Beta test the prototype for possible design
and control problems.
Evaluation
• At this stage the system is evaluated
against its stated goals. Different types of
evaluation approaches including formative
or summative could be used.
– Formative evaluation is like doing system
verification (see whether it works perfectly)
– Summative evaluation involves letting users
to use the system and getting feedback from
them if it works according to the requirements.