Unit 4 and 5

Fundamentals of Multimedia, Chapter 3
UNIT- IV
• FILE FORMATS
•INPUT & OUTPUT DEVICES
• STORAGE TECHNIQUES
7/30/2008 Li & Drew

File Formats
Different applications (programs) store data in different
formats. Applications support some file formats and not
others.
File formats appear as a (usually) 3 letter suffix or
“extension” after the name of the file, e.g., .psd, .doc,
.jpg, .pct, .tif, .gif, .ppt, etc.

GIF
• GIF standard (Graphics Interchange Format):
Limited to 8-bit (256) color images only, which, while
producing acceptable color images, is best suited for
images with few distinctive colors .
• GIF standard supports interlacing — successive
display of pixels in widely-spaced rows by a 4-pass
display process.
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GIF
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GIF
• For the standard specification, the general file format of a GIF file is as
in following fig.
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JPEG
• JPEG (Joint Photographic Experts Group): The most important
current standard for image compression (.jpg, .jpeg, .jpe).
• The human vision system has some specific limitations and JPEG
takes advantage of these to achieve high rates of compression.
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A photo of a flower compressed with successively more lossy
compression ratios from left to right.
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Fig. 3.17: JPEG image with low quality specified by user.
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PNG
• PNG format: standing for Portable Network Graphics — meant to
supersede the GIF standard, and extends it in important ways.
• Special features of PNG files include:
1. Support for up to 48 bits of color information — a large increase.
2. Files may contain gamma-correction information for correct display
of color images, as well as alpha-channel information for such uses as
control of transparency.
3. The display progressively displays pixels in a 2-dimensional fashion
by showing a few pixels at a time over seven passes through each 8
8 block of an image.
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TIFF
• TIFF: stands for Tagged Image File Format.
• The support for attachment of additional information (referred to as
“tags”) provides a great deal of flexibility.
1. The most important tag is a format signifier: what type of
compression etc. is in use in the stored image.
2. TIFF can store many different types of image: 1-bit, grayscale, 8-
bit color, 24-bit RGB, etc.
3. TIFF was originally a lossless format but now a new JPEG tag allows
one to opt for JPEG compression.
4. The TIFF format was developed by the Aldus Corporation in the
1980's and was later supported by Microsoft.
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Input and Output Devices
7/30/2008 Li & Drew

I/O Devices: Input
• An input device one that, together with appropriate
software, transforms iinnffoorrmmaattiioonn from the user into ddaattaa
that the computer application can process.
• Choice and method of use of an input device should
contribute positively to uussaabbiilliittyy of the system
• The usability of an input device depends greatly on the
provision of appropriate ffeeeeddbbaacckk
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Pointing devices: cursor control
• 33DD ttrraacckkeerr
– Relays position and orientation to a receiver. Replaces mouse where
desk space is limited (e.g., laptops)
• JJooyyssttiicckk
– Small stick, movable in any direction in a fixed socket.
• MMoouussee
– continuous input device. Buttons for discrete input. Relative device.
• TTrraacckkbbaallll (a.k.a. “dead mouse”)
– Rotatable ball in fixed socket
• TTaabblleett
– used with stylus or puck. Absolute device
• MMoollee (a.k.a. “foot mouse”)
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• DDaattaagglloovvee
– Communicates hand and finger position to an application. Used
for manipulating virtual objects
• TToouucchh--sseennssiittiivvee ssccrreeeenn
– Special screen that detects the position of a finger touching it.
• LLiigghhtt ppeenn
– Location found by beam passing through screen during refresh
cycle
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Choosing appropriate input devices
• Matching devices with wwoorrkk
– The particular manipulations needed to accomplish a piece of work need
to be analyzed
– Natural mappings between use, feedback, meaning of result and user’s
mental model are needed
• Matching devices with uusseerrss
– e.g., eye and head input for the physically disabled
• Matching devices with eennvviirroonnmmeenntt ooff uussee
– space
– relation to other concurrent tasks etc.,
7/30/2008 Li & Drew

Types of Storage
• Magnetic Disk Storage
• Optical Disks
– Magneto-optical
– CD-ROM
– CD-R
– CD-RW
– DVD-ROM
• Magnetic Tape Storage

Magnetic Disk Storage
• Data represented as magnetic spots
– Magnetized spot = 1
– Absence of a magnetized spot = 0
• Read
– Converts the magnetized data to electrical
impulses
• Write
– Converts electrical impulses to magnetized spots
on disk

High-Capacity Portable Disks
• Larger files
• Portable
• High-capacity
– 120 / 200 MB
– Can read and write standard diskettes
– Ex: Superdisk
• Zip disk
– 250 MB
– not compatible with 3 ½ inch diskettes

Hard Disk
• Various sizes
• Portability
– Generally non-portable
– Removable hard disks available for PC
• Rigid platter coated with metallic
substance

Disk Drive
Read / Write Operation
• Disks rotate
• Access arm moves read/write
head
• Read / write operation
begins and continues until
complete
• Data is transferred to/from
memory

RAID
Redundant Array of
Independent Disks

Optical Disk
• Greater capacity than other portable media
• Process
– Laser writes on metallic material spread over the
surface of disk
– Heat from laser produces pits on disk surface
– Reading – laser picks up light reflections from the pits
• Technology
– ROM
– WORM

MO
Magneto-optical
• Hybrid
• High-volume capacity
• Written multiple times
• Process
– Laser melts a microscopic spot
– Magnet aligns crystals
– Reading – laser picks up light reflection from crystals

CD-ROM
Compact Disk Read-Only Memory
• High capacity portable
• Read multiple times
• Cannot record
• Capacity – up to 680 MB (450
standard 3 ½ inch diskettes)
• Used for software distribution

CD-R
Compact Disc-Recordable
• High capacity
• Portable
• Write once
– CD-R drive
– CD-ROM drive

CR-RW
Compact Disk-Rewritable
• High capacity
• Portable
• Record multiple times
• Some compatibility problems reading CD-RW
disks on CD-ROM drives

DVD-ROM
Digital Versatile Disk
• Larger capacity than CD-ROM
– Standard – Up to 4.7 GB, 7 times more than CD-ROM
– Double layers – 8.5 GB
– Double-sided – 17 GB
• Data is packed more densely
• Read multiple times, Cannot record
• Can read CD-ROM disks

Digital Versatile Disk
• Benefits
DVD-ROM
– Full-length movies
– Audio quality comparable to audio compact disks
– High-volume business data
• Expected to replace CD-ROM in the near
future

UNIT 5
• Multimedia Authoring
• Hypertext
• Hypermedia
• Distributed Multimedia

Multimedia Authoring Tools
• Multimedia authoring tools provide the
important framework that Multimedia
designers require to organises and edit the
various elements of a multimedia projects
including, Video, Sound, Animation, Graphics
and Text.
• Authoring tools are used for designing
interactivity and User Interface.

Multimedia Authoring Tools II
• There are three general categories
of Multimedia authoring tools.
• These are:
– Card or page-based tools
– Icon-based tools
– Time-based tools
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Multimedia Authoring Tools III
• Card - or Paged based tools
– Are systems that are based on a book
or a page metaphor. This means that
the way the elements are organized are
similar to pages of a book or a card
file.
– E.g. Hypercard
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Multimedia Authoring Tools III
• Card - or Paged based tools
– Are systems that are based on a
book or a page metaphor. This
means that the way the elements are
organized are similar to pages of a
book or a card file.
– E.g. Hypercard
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Multimedia Authoring Tools IV
• Icon-Based Tools
– These authoring tools multimedia
elements are organised as objects
in a structural framework. The
programme typically displays
flow diagram of activities along
branching paths
– E.g Macromedia Authorware
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Multimedia Authoring Tools V
• Time-Based Tools
– These authoring systems view the
development of a multimedia
package as organising objects along
a time line. Sequentially organised
frames are then played back to the
user.
– E.g Macromedia Director
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HYPERTEXT and HYPERMEDIA
7/30/2008 Li & Drew

Hypertext
• Hypertext is a system of storing images,
text, and other computer files that allows
direct links to related text, images, sound,
and other data.
• Hypertext is the main basis of operation for
the web.

Hypermedia
• Hypermedia is an updated extension of text
in hypertext.
• It is the connection between hypertext and
multimedia.
• Hypermedia documents contain links to
other pieces of text, sound, images, movies,
and other forms of media.

How Hypertext is Different From
Hypermedia
• Like regular text, hypertext can be edited,
stored, searched or read. Unlike regular
text, it can also contain connections to other
documents.
• Hypermedia documents are like hypertext,
except that they also contain links to other
forms of media like movies, sound, and
images.

Uses of Hypermedia/Hypertext
• As an educational tool
• As a way of navigating the internet.
• A way of organizing content in a database.
• As a way of allowing users with disabilities to learn.
• Entertainment.
• Making online purchases.
• Not just for the internet. Can be used in other applications
such as dictionaries, encyclopedias, databases, and
presentations.

Distributed Multimedia
What is Distributed Multimedia?
 Large quantities of distributed data
 Typically streamed out
 One or many receivers of the data
 Run over general purpose infrastructure
 Data is time sensitive, but not necessarily real
41
time

DMMS
• A simple architecture of DMMS

Distributed Multimedia,
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Four Phases
 Encoding
 Storage (not always required)
 Transport
 Decoding
cont.

Unit 4 and 5

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