Multimedia in Web
Introduction
Multimedia Elements in Web Page
Images
 Voice
 Music
 Animation
 Video
 Text & Numbers

Digitalization
Contents  Numbers (0’s & 1’s)
 For computers and the Internet
 Different media originated and
developed differently, e.g. sound &
image  Different formats
 Accessibility: http://www.w3c.org/WAI/

Pixels

Picture element
 Values in color and brightness
Role of Bandwidth
Volume of data can transmit in one
second
 56K (Dial-up)
 ISDN 128 Kbits/sec
 DSL and Cable (Broadband)
512 Kbits/sec
 T1 1.5 Mbits/sec
 Ethernet 10-100 Mbits/sec

Data Compression
Digitalization  Compression 
Decompression
 Codecs = Compression + Decompression
 Removing repetition:
e.g. 405 405 405 405 405  405 X 5

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Averaging: e.g. 378 379 378 376  378 X 4

Range Reduction: e.g. 8 bit (256)  6 bit (64)
Sound loudness can be expressed in 256
levels or 64 levels.
File Formats

Images
GIF
 JPEG
 PNG


Sound
AIF (Audio Interchange File)
 QuickTime


Video
QuickTime (mov)
 Window Media
 RealVideo


Animation

Flash
Viewer Capacity Consideration

Bandwidth


Screen size & resolution

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Speed test at http://sea.speakeasy.net/
640 X 480 pixel screen
Processor
Video System, Ram, & BUS
Firewall
Plug-Ins: e.g. Flash Player
Browser
Experience

Find types of images used
Go to http://www.moma.org/
 Right-click on images  Properties

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Movies:
http://www.atomfilms.com/
 http://www.ifilm.com/
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