Introduction
to
Multimedia
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia
❑
The word is composed of two parts
❑
Multi: from the latin word multus which
means numerous.
❑
Medium: the plural of the latin word medium
which means middle or center.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Media
❑
A means to distribute and represent
information.
❑
Ex.: text, graphics, pictures, voice,
music.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia
❑
Multimedia is media that utilizes a
combination of different content forms.
A collection of CDs is not multimedia.
❑
The term can be used as a noun (a
medium with multiple content forms) or
as an adjective describing a medium as
having multiple content forms.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia Categories
❑
Multimedia may be broadly divided into
linear and non-linear categories. Linear
active content progresses without any
navigation control for the viewer such as
a cinema presentation. Non-linear
content offers user interactivity to control
progress as used with a computer
game.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia Categories
❑
Multimedia presentations can be live or
recorded. A recorded presentation may
allow interactivity via a navigation
system. A live multimedia presentation
may allow interactivity via interaction
with the presenter or performer.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Usages of Multimedia
❑
Commercial (advertising), Entertainment
(special effects), Arts (media artists),
Education (computer learning),
Engineering (training, simulations),
Industry (information broadcasting),
Science and medicine (simulations),
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia Features
❑
Multimedia presentations may be
viewed in person on stage, projected,
transmitted, or played locally with a
media player. Broadcasts and
recordings can be either analog or
digital electronic media technology.
Digital online multimedia may be
downloaded or streamed. Streaming
multimedia may be live or on-demand.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Perception Media
❑
Refers to the nature of information
perceived by humans.
❑
Auditory media (music, sound and
voice) are different from visual media
(text, graphics, still and moving
pictures).
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Representation Media
❑
How is information represented
internally to the computer.
❑
Ex.: ASCII text, GKS graphics, PCM
sound, JPEG image, NTSC television
signal.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Presentation Media
❑
Refers to the physical means used by
systems to reproduce information for
humans. The actual device presenting
the media.
For television: CRT + loudspeakers.
❑
Input (keyboards, cameras, mikes) and
output (paper, monitors, speakers)
presentation media.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Storage Media
❑
It is used in computing to refer to the
various physical means to store data
like tapes or disks.
❑
Paper is also storage media.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Transmission Media
❑
Refers to the physical means that allow
transmission of multimedia information
(cables, radio towers, satellites,
Internet).
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Information Exchange
Media
❑
Include all data media used to transport
information. In fact, all storage and
transmission media.
Ex.: removable disks, microfilms, paper,
floppy disks, CD's, DVD's.
❑
Also direct exchanges via cables, optical
fibres, radio waves.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Presentation Spaces
❑
Paper and computer monitors are
examples of visual presentation spaces
as is a slide-show projected from a
computer.
❑
Stereophony and quadrophony are
examples of acoustic presentation
spaces.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Presentation Values
❑
Determine how information from various
media is represented.
❑
Text is the medium presenting a sentence
visually. Pressure waves can present a
voice.
❑
We need a code to interpret the
presentation values (ex. alphabet).
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Presentation Values
❑
These symbols have
meaning only if you
know the context.
❑
These include cultural
gestures.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Presentation Dimensions
❑
Each presentation space has one or
more presentation dimension.
❑
A computer monitor has 2 dimensions.
❑
Time can be an additional dimension
within each presentation space. There
are two kinds of media with regard to
time dimensions.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Discrete Media
❑
Text graphics and pictures are called
discrete media as they are composed of
time-independent information items.
❑
Discrete media are better processed as
fast as possible since time is not a
critical factor for its comprehension.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Continuous Media
❑
Sound and motion videos are called
continuous media because they require
a continuous play out to be understood.
They are time-dependent
❑
Continuous media are better processed
in the respect of the time dependency.
❑
The correctness of the media depends
of the time condition.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Continuous Media
❑
A silent movie is not purely a continuous
media but there is a time constraint
nonetheless.
❑
Continuous vs. discrete has nothing to
do with internal representation. It refers
only to the viewer or auditor perception.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Multimedia Systems
❑
A multimedia system must be computercontrolled.
❑
It is integrated: It involves a minimal number
of different devices.
❑
Must be able to handle both continuous and
discrete media.
❑
Individual media must be independent.
❑
Must be synchronized. A text with graphics is
not multimedia.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Data Streams
❑
Networked multimedia systems transmit
both discrete and continuous media
streams.
❑
Information is split in packets before it is
transmitted.
❑
The packets are sent by one system
(computer) (source) and received by
another (sink).
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Asynchronous
Transmission Mode
❑
When a sender and receiver do not
need to coordinate before data can be
transmitted.
❑
Transmission may start at any instant.
❑
Ex.: Sending a text.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Synchronous
Transmission Mode
❑
When a sender and receiver need to
coordinate before data can be transmitted.
❑
Transmission may only take place at welldefined times.
❑
A clocking signal is necessary.
❑
Ex. : A live television show.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Isochronous Transmission
Mode
❑
A periodic signal, pertaining to transmission in
which the time interval separating any two
corresponding transmissions is equal to the
unit interval or a multiple of the unit interval.
❑
The Isochronous Transmission Format is also
known as START-STOP mode or
CHARACTER mode.
Ex.: Transmission of a video over a network.
❑
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Continuous Media Data Streams
❑
The first property of data streams
relates to the time intervals between
completed transmissions of consecutive
information units or packets.
Strongly periodic data stream
T
Weakly periodic data stream
T
1
T
T
2
T
3
T
Aperiodic data stream
T
1
T
2
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Continuous Media Data Streams
❑
The second property of data streams
concerns how the data quantity of
consecutive information units or packets
varies.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Continuous Media Data Streams
D1
T
t
Strongly regular data stream
D1
D1
Weakly regular data stream
T
D2
D3
D1
t
D2
D3
Irregular data stream
t
D1
D2
D3
Dn
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Continuous Media Data Streams
❑
The third property of data streams
concerns the continuity or the
relationship between consecutive
packets.
Interrelated data stream: without gaps
D1
D2
D3
D4
D
Non-interrelated data stream: gaps between packets
D1 D2
D3
D4
D
IF NETWORK IS FASTER THAN MEDIA DELIVERY
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Information Units


Continuous media consist of a timedependent sequence of individual
information units called Logical Data Units
(LDU).
A symphony consists of independent
movements.

A movement consists of notes.

Notes are sequences of sampled sounds.
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
Granularity

A single image is not the only possible LDU
in a motion video sequence. Each scene
and each pixel are also logical data units.
Film
Clip
Frame
Blocks
Pixels
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University
END OF LESSON
2. Introduction to Multimedia - Copyright © Denis Hamelin - Ryerson University