Multimedia involves integrating different types of digital media like text, graphics, images, audio and video. A multimedia system processes multimedia data using a computer and digitally represents all information. It has an interactive interface and integrated components. Multimedia applications include interpersonal communication using video calls, interactive websites, and entertainment like video on demand.

1. Introduction to Multimedia
BY : Selma Abdelbagi Ibrahim

2. What is Multimedia
• Multimedia means that computer information can be
represented through audio, video, and animation in
addition to traditional media (i.e., text, graphics drawings,
images).
• A good general definition is:
• Multimedia is the field concerned with the computer-
controlled integration of text, graphics, drawings, images
,Video, animation, audio, and any other media where
every type of information can be represented, stored,
transmitted and processed digitally.

3. Multimedia Systems
• A Multimedia System is a system capable of
processing multimedia data and applications.
• A Multimedia system has four basic characteristics:
 Multimedia systems must be computer controlled.
 The information they handle must be represented
digitally.
 The interface to the final presentation of media is
usually interactive.
 Multimedia systems are integrated.

4. Desirable Features for a Multimedia
System
 Very High Processing Power:
• To deal with large data processing and real time
delivery of media.
• Special hardware commonplace.
 Capable File System
• To deliver real-time media -- e.g. Video/Audio
Streaming.
• Special Hardware/Software needed

5. Desirable Features for a Multimedia
System
 Data Representations/File Formats
• should be easy to handle yet allow for compression
/decompression in real-time.
 Efficient and High I/O
 Special Operating System
 Large Storage and Memory
 Network Support
 User friendly Software Tools

6. Components of a Multimedia System
 Capture devices
• -- Video Camera, Video Recorder, Keyboards, mice.
 Storage Devices
• Hard disks, CD-ROMs, DVD, etc
• Communication Networks
• Ethernet, Token Ring, FDDI, ATM, Intranets, Internets.
• Computer Systems
• Multimedia Desktop machines, Workstations
 Display Devices
• speakers, monitors, Colour printers etc.

7. Multimedia information
representation
• Applications involving text and images comprise
blocks of digital data
 Text: block of characters with each represented by a
fixed number of bits (codeword)
• Digitized Image : comprises a two dimensional
block of what are called picture elements with each
element represented by a fixed number of bits .
• Application involving audio and video represented
by analog signal

8. Multimedia information
representation
• In application that involve a single type of media the
basic form of representation of the particular media
type is often used .
• In the applications that involve text and images or
audio and video their basic form is often use since the
two media types have the same form of representation
• In application that involve the different media type
integrated in some way it becomes necessary to
represent all media types in a digital form.

9. Multimedia networks
• Telephone networks
• Data networks
• Broadcast television netwoks
 Cable network
 Satellite network
• Integrated services digital networks(ISDN)
• Broadband multiservice networks (B-ISDN)
 ATM
 Frame Rely

10. Multimedia applications
• A Multimedia Application is an Application which
uses a collection of multiple media sources e.g. text,
graphics, images, sound/audio, animation and/or
video.
• They can be placed into one of three categories :
 Interpersonal communications
 Interactive application over internet
 Entertainment applications

11. Interpersonal Communications
Speech only :
 Telephony
• Provided using PSTN/ISDN/cellular phone network.
• User can take part in telephone calls through the PC.
• This required computer telephony integration (CTI)
 Voice mail:
• Spoken message is left in voice mailbox located in
voice mail server.

12. Interpersonal Communications
 Teleconferencing calls:
• Multiple interconnected telephones/PC.
• Each person can hear and talk to all of the others
involved in the call.
 VoIP:
• Telephony over the internet is also known packet
voice

13. Interpersonal Communications
Image only:
• Exchange of electronic image of document Over
PSTN / ISDN .
• This simply known as fax.
• To send a document the sender keys in the telephone
number of intended recipient and a circuit is set up
through the network in the same way as for a
telephone call.

14. Interpersonal Communications
Text only :
• An example is electronic mail over the internet.
• Associated with each network is a set of one or more
server computers (e-mail server) that contain a
mailbox for each user.
Text and image
• An example is computer-supported cooperative
working (CSCW) .
• A distributed group of people –each in his or her
place of work-are all working on the same project.

15. Interpersonal Communications
• A window on each person’s display is used as a shared
workspace/ whiteboard.
• The display comprises text and images integrated
together.
• The software associated with CSCW comprises a central
program known as whiteboard program that is made up of
tow parts: a change notification part and an update control
part.
• Whenever a member of the group updates the contents of
his or her white board, the change notification part sends
details of the changes to the whiteboard program.

16. Interpersonal Communications
• This relays the changes to the update control in each
of the other PCs which in turn proceed to update the
contents of their copy of the whiteboard.
 Speech and video
• An example is video telephoning
• Supported by all the networks types.
• The terminals incorporate a video camera,
microphone and speaker.
• The integration of the video with speech requires
more bandwidth than that required for speech only.

17. Interpersonal Communications
• A call may involve several people (a desktop
videoconferencing).
• A separate window on the screen of each participant’s
PC should be used to display the video image of all
the other participants.
• This would require multiple integrated
communication channels, one for each participant.
• In case of enterprise network, In order to support
videoconferencing there is a central unit called
multipoint control unit(MCU).

18. Interpersonal Communications
• Alternatively networks such as LANs and the internet
support multicasting. Thus MCU is not required.
• There are applications that involve groups of people
at one or more of the locations such as remote lecture
and group video conferencing .
• Remote Lecture has similar requirements to those for
two party video call .
• If the lecture is being relayed to multiple locations
either a separated channel is require to each remote
site or an MCU is used .

19. Interpersonal Communications
• In the case of group videoconferencing , an equipped
room called a videoconferencing studio is used .
• videoconferencing studio contains all the necessary
audio and video equipment : video camera , large
screen display , and associated audio equipment all of
which is connected to a unit called videoconferencing
system.
• A conference can involve two locations and or more .
• In the case of the later, an MCU is used.

20. Interpersonal Communications
Multimedia
• An example mail that containing many types media type :
• Voice mail:
• Internet based voice mail
• In addition to e-mail server there is also a voice mail
server associated with each network .
• Multimedia mail
• The textual information is annotated with a
digitized image , speech or video.

21. Interpersonal Communications
• The annotation can be sent together with
original textual message and hence stored and
played out in the normal way.
• Alternatively The annotation can be requested
by the recipient when the textual message is
being read.

22. Interactive applications over the
internet
Web server
• The internet is used to support a range of interactive
applications , the most widely used being for
interaction with World Wide Web (WWW) or simply
Web server .
• Web server comprises a linked set of multimedia
information severs that distributed around the
internet .
• The information stored on all servers is equivalent
to a vast library of document .

23. Interactive applications over the
internet
• Each document comprises a linked set of pages and
linkage between these pages known as hyperlinks .
• Hyperlinks references either to other pages of the
same document or to any other document within the
total Web.
• Document comprising only text are created using
what is called hypertext , while those comprising
multimedia information are created what is known as
hypermedia .

24. Interactive applications over the
internet
• Each document has a unique address – known as a
uniform resource locater (URL) .
• URL identifies both the location of the sever on the
internet where the first page of the document is stored
and the file reference on that sever .
• The first page of the document is known as home
page .
• A standard format is used for writing documents

25. Interactive applications over the
internet
• This known as hypertext markup language (HTML)
• HTML is also used to write client software to explore
the contents of the Web.
• The client function is called browser .

26. Entertainment applications
Movie or video on demand
• Video and audio on demand associated with
entertainment must be of higher quality / resolution.
• A digitized movie/video - with sound – requires a
minimum channel bit rate (bandwidth) of 1.5 Mbps.
• The network used to support this type of application
must be either a PSTN with high bit rate modem or
cable network.
• A collection of digitized movie/video stored on a
server .

27. Entertainment applications
• Subscriber terminal comprises a television with a
selection device for interaction purposes .
• The user interactions are relayed to the server through
a set up box .
• A key feature of video / movie on demand is that a
subscriber can initiate the showing of the movies at
any time of the day or nigh .
• This means that the server must be capable of playing
out simultaneously a large number of video streams
equal to the number of subscribers currently watching
a movie .

28. Entertainment applications
• If the server is supporting large number of subscribers
, then it is common for several subscriber to request
the same movie within a short time interval between
each request .
• An alternative mode of operation is near movie on
demand (N-MOD)
• In N-MOD requests for a particular movie are not
played out are queued until the start of the next play
out time of that movie .

29. Entertainment applications
• In this way , all request are satisfied simultaneously
by the server outputting a single video stream.

30. Entertainment applications
Interactive television
• By connecting appropriate terminal equipment to the
STB – a key board , telephone and so on – the
subscriber is able to gain service provided through the
PSTN .
• Then the subscriber is able to actively respond to the
information being broadcast.