Introduction to Multimedia Systems

221 Pages·2002·10.14 MB·English

by  Gaurav Bhatnagar

Introduction to
Multimedia Systems
This Page Intentionally Left Blank
Introduction to
Multimedia Systems
Editors
Gaurav Bhatnagar
Shikha Mehta
Sugata Mitra
Centre for Research in Cognitive Systems (CRCS)
NIITUd.
New Delhi, India
ACADEMIC PRESS
A Harcourt Science and Technology Company
San Diego San Francisco New York Boston London Sydney Tokyo
Cover art: © 2001 John Foxx Images
This book is printed on acid-free paper, w
Copyright © 2002 by ACADEMIC PRESS
All Rights Reserved.
No part of this publication may be reproduced or transmitted in any form or by any
means, electronic or mechanical, including photocopy, recording, or any information
storage and retrieval system, without permission in writing from the publisher.
Requests for permission to make copies of any part of the work should be mailed to:
Permissions Department, Harcourt Inc., 6277 Sea Harbor Drive,
Orlando, Florida 32887-6777
Explicit permission from Academic Press is not required to reproduce a maximum of
two figures or tables from an Academic Press chapter in another scientific or research
publication provided that the material has not been credited to another source and that
full credit to the Academic Press chapter is given.
Academic Press
A division of Harcourt, Inc.
525 B Street, Suite 1900, San Diego, Cahfomia 92101-4495, USA
http://www.academicpress.com
Academic Press
Harcourt Place, 32 Jamestown Road, London NWl 7BY, UK
http ://www. academicpress .com
Library of Congress Catalog Card Number: 2001092781
hitemational Standard Book Number: 0-12-500452-4
International Standard Book Number: 0-12-500453-2 (International edition)
PRINTED IN THE UNITED STATES OF AMERICA
01 02 03 04 05 06 MB 9 8 7 6 5 4 3 2 1
Contents
Preface vii
Note to Students xi
Prelude to Multimedia 1
Sugata Mitra
Overview of Multimedia Systems 3
Caurav Bhatnagar
Prelude to Audio 11
Sugata Mitra
The Nature of Sound 13
Harita Gupta
Introduction to Digital Audio 21
Harita Gupta
Audio Editing 31
jude D'Souza
Music and Speech 39
jude D'Souza and Harita Gupta
An Interlude: Free for All 49
Sugata Mitra
Audio: From CD to the Web 51
Harita Gupta
The WAV File Format 55
jude D'Souza
Prelude to Graphics 61
Sugata Mitra
V
vi CONTENTS
8 The Paint Shop Pro Interface 63
Renu Ahuja and Caurav Bhatnagar
9 Colors 73
Gaurav Bhatnagar
An Interlude: The Properties of Light 79
Gaurav Bhatnagar
10 File Formats and Web Graphics 85
Renu Ahuja and Gaurav Bhatnagar
11 Layers and Filters 93
Gaurav Bhatnagar
An Interlude: Vision 97
Gaurav Bhatnagar
12 Process of Animation 103
Renu Ahuja and Gaurav Bhatnagar
13 Video 113
Manish Mangrulkar and Manu Yadav
An Interlude: The Term Dimension 123
Gaurav Bhatnagar
14 3-D Graphics 127
Manish Sinha
15 Text in Multimedia and the Internet 137
Renu Gupta
An Interlude: Meaning in Binary Strings 151
Sugata Mitra
16 Art and Design 161
Gaurav Bhatnagar
17 Cognitive User Interfaces 171
Gaurav Bhatnagar
An Interlude: Development of Cognitive Systems 181
Sugata Mitra
18 Authoring Multimedia in Visual Basic 191
Himanshu Tayal
Index 205
Preface
Learning to make digital multimedia on a computer is a bit like learning a language. Not
a computer language like Visual Basic or C++ but languages like English or German. This
is because multimedia is more about communication between human beings than about
technology.
Digital multimedia is defined as any combination of graphics (2-D and/or 3-D), audio,
text, animation and real-life video delivered through the computer. In addition, the notion
of interactivity differentiates digital multimedia from the traditional forms of media and is
an integral part of multimedia.
Since we are dealing with digital multimedia, all of the above-mentioned elements have
to be stored in a digital or discrete format, as opposed to the largely analog formats used
by traditional mass media. Thus the multimedia expert will have to be able to do the
following, for each media:
Convert analog media into a suitable discrete format.
For example, a photograph may have to be scanned and stored on the hard drive of the
computer. Or a video may have to be "grabbed" or digitized.
Since data in digital format is discrete, a decision needs to be made about how to sample
the analog data. For example, theoretically, the straight line that you draw on paper has an
infinite number of points. But when drawn on the monitor, only a finite number of points
can be drawn. How close should the points be so that our eyes cannot tell the difference?
Similarly, when using a printer to print a line, how many dots of ink per inch should the
printer throw on the paper, for our eyes to perceive it as a straight line? Obviously, the
more data that you keep to describe the analog media, the better quality you will get.
However, a large amount of data may be impossible to store given the restrictions of your
hard disk. Thus the multimedia programmer should be able to:
Decide the "resolution" to be used when storing the data, based on the application,
the quality of the desired output, and the restrictions of the storage medium.
Obviously, if possible, we would like to have the highest quality possible. Using appropriate
vii
viii PREFACE
compression technologies, it is possible to compress digital data and reduce the file size
but still keep adequate quality. For example, on the Internet, currently two graphics file
formats are very popular and supported widely. These are the GIF and JPEG formats.
While GIFs give good quality for cartoons and animated characters, JPEG is used for
putting photographs on the Internet. A graphics expert in a Web-development team is able
to use the right format, and adjusts the file size using these compression technologies. In
general, the multimedia programmer should be able to:
Use appropriate compression technologies and file formats for storing the media
elements.
Once the file is stored in a particular file format, you may require a special player or an
editor to view and/or edit the files. For example, MP3 is a popular format for CD quality
music files on the Internet. When such a song is downloaded on your PC, you will need a
special MPS player to play the song. As another example, consider Paint Shop Pro, a
popular graphics software. Using this package you can edit various graphics files and save
them in JPEG or GIF formats as required. You may also be able to give "special effects"
to previously made or scanned graphics. You can make screen grabs. And you can do all
this, regardless of whether you took any art classes in school! In general, for any media
element, a multimedia expert should be able to:
Edit a given media element using an appropriate editor.
Finally, the multimedia expert should be able to:
Integrate all the media elements into one multimedia system using a programming
language or an authoring package.
In this book we cover these topics for each media element.
We believe that people learn much more by experimenting with software packages and
talking to friends, rather than by reading any large tomes or by messing with the complicated
manuals written for practicing professionals. Our book gives exercises to encourage these
constructionist learning mechanisms. A Web page containing links to many of these free
software packages www.academicpress.com/multimedia. There are also links to sample
images, sounds, etc., that the students can use for educational purposes.
Each chapter tries to highlight the main features of software packages, without referring
to any commercial (and expensive) software. The philosophy is that multimedia experts
should not be software dependent, since a specific software package may not be available
at a given time. We enable our readers to become self-educated when where it comes to
learning software packages, by showing them the principles behind their central features.
All the software packages that are referred to in this book are freeware or have evaluation
versions freely available on the Internet.
As far as the Internet is concerned, we discuss the concerns of the Web developer in
terms of file formats and bandwidth restrictions. Since this is a very fast growing area, the
emphasis is on fundamentals and how developers can keep in touch with the changing
trends and technologies in this area.
We prepared this book using a process analogous to multimedia production. Experts in
the R&D Centre of NUT Ltd. wrote the various sections. Later, the various elements of this
PREFACE ix
book were stitched together by its editors. Their role was similar to the role played by the
designers and programmers in a multimedia production. A preliminary version of this book
was used in one of NIIT's centers, for a 10-week course on multimedia.
This book should be suitable for young adults in high school or college who have some
programming background and have worked on the Windows platform, and who are keen
to learn how to make multimedia systems. If students already know some programming
language like Visual Basic or Java, they will be able to make their own stand-alone or Web-
based multimedia systems. If not, they can still use MS-PowerPoint and make interesting
interactive presentations.
Gaurav Bhatnagar, Shikha Mehta, and Sugata Mitra
New Delhi, December 6, 1999