Transcript - Binus Repository

Matakuliah
Tahun
: T0732 / Sistem Multimedia
: 2007
Perancangan Multimedia untuk
World Wide Web
Pertemuan 12
Learning Outcomes
Pada akhir pertemuan ini, diharapkan mahasiswa akan
mampu :
• menyesuaikan desain aplikasi multimedia untuk
penggunaan di World Wide Web
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Outline Materi
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Teknologi WWW
Authoring Tools untuk WWW
Desain untuk WWW
Konsiderasi untuk Elemen-Elemen Multimedia
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WWW Technology
• HTML (HyperText Markup Language)
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DHTML (Dynamic HTML)
XML (eXtensible Markup Language)
SMIL (Synchronized Multimedia Integration Language)
VRML (Virtual Reality Markup Language)
• Browser supports
– Plug-in media handlers: allows movies, multimedia files to be
viewed via native browser, ex : shockwave plugin, Quicktime VR,
real audio, acrobat reader
– JAVA Script: allows transfer of applets, small programs via HTTP
and execute in browser.
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Web Pages
• Web pages are made up of basic text documents
• Can be created in any text editor such as Notepad
• Multimedia elements (except text) are stored external to the
document
• HTML defines the format (look) and functionality (feel) of web
pages and provides the links to external resources
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HTML Advantages
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Small file sizes
Does not require expensive authoring tools
Web space is inexpensive
Does not require programming skills
Provides links to external locations & downloads
Once uploaded, provides “Instant Publication”
Can be viewed on any computer with free web browsing
software
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HTML Disadvantages
• What you design will not
necessarily appear the same
on every computer!
• No single HTML standard
• Different browsers support
different/unique HTML tags
• Different hardware affects
final result
• Hypertext only provides
limited interaction
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Authoring Tools for WWW
• Macromedia Dreamweaver
• Microsoft Frontpage
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Design Issues
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Different Browsers
Monitor and Window size
Bandwidth
Accessibility
Usability
http://www.apis.ca/Understanding_Websites/Good_Sites_Bad_Sites/What_makes_a_good_website.htm
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Different Browsers
• Not all web browsers support
proprietary features, eg
different implementations of
DHTML
• Browser settings affect final
product
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Fonts selected and installed
Colour of background
Hypertext colours
Autodownloading images
Window size
Browser Statistic
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IE 6
IE 7
Firefox
Netscape
51%
21%
12%
11%
Safari
IE 5
Opera
Mobile
3%
1%
1%
0.3%
http://www.thecounter.com/
http://www.upsdell.com/BrowserNews/stat.htm
Monitor and Window Issues
• Many people are surfing the web with various screen
resolution and different sized window screens.
• Recommendation  use liquid design when designing
your web pages.
• You may want to design for the commonly used screen
resolution.
• Personal Digital Assistants (eg Palm, Windows CE, and
other WAP devices have small low resolution screens)
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Liquid Design
• Liquid design  the web site adapts itself to the
available space, the same way water takes the shape of
the glass it is in.
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Bandwith
• The rule of thumb for a person using a 28.8k modem is 2
kps to transfer web graphics.
• Example : a standard 40k graphic might take 20
seconds to display on your users browser.
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Accessibility Issues
• Visual Impaired Users
– Cannot access images that are used to convey content or to assist
navigation
– Have difficulty distinguishing important screen elements or text where
background images are used.
• Solution
– Provide ALT text for short descriptions of graphics, use & Longdesc
attributes or links out for longer pieces
– Lots of motion, flashing etc can be disconcerting so avoid client-based
refresh & redirection, lots of animated gifs etc
– Avoid using frames or unnecessary tables
• How accessible is your site?
http://www.w3.org/WAI/ER/existingtools.htm
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Accessibility – ALT text
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The Ten Most Violated Homepage Design Guidelines
by Jacob Nielsen
1.
Emphasize what your site offers that's of value to users and how your
services differ from those of key competitors
2. Use a liquid layout that lets users adjust the homepage size
3. Use color to distinguish visited and unvisited links
4. Use graphics to show real content, not just to decorate your homepage
5. Include a tag line that explicitly summarizes what the site or company does
6. Make it easy to access anything recently featured on your homepage
7. Include a short site description in the window title
8. Don't use a heading to label the search area; instead use a "Search"
button to the right of the box
9. With stock quotes, give the percentage of change, not just the points
gained or lost
10. Don't include an active link to the homepage on the homepage
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Text for Web
• Users may choose to view the website in their preferred font (done
by setting user preference in the browser)
• Standard font face : Times New Roman, Courier, etc
• For flexibility in font management : CCS (Cascading Style Sheets)
– CCS is available in DHTML
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Images for Web
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Standard format : GIF, PNG, JPEG
Other format may require special plug-ins.
GIF and PNG are lossless and support transparency
PNG  GIF replacement
JPEG  lossy compression, ten times more compressed than
GIF
• Macromedia Fireworks is designed specifically for creating
graphics for web pages.
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Sound for Web
• Standard format : AU, Wav, MIDI  embedded
• MIDI is commonly used for background music
• Wav is big in size
– 11khz, 8 bit mono  reduced quality but still audible
• Using plugin : Shockwave Audio (swa),
QuickTime
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Animation for Web
• HTML Tag : <blink> and <marquee>
• Javascript
• Animated GIF (GIF89) can be used to make simple cell
animations
• Animation Plug-ins/players : Director, Flash,
QuickTimeVR
Note : While animation is good for attracting
user’s attention, take care not to use blinking
animation for reading text.
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3D for Web
• VRML
• Macromedia Director
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Flash or non-Flash?
• Flash Advantages
– Current Trend
– Great Design
– Full control and flexibility for designers to design interactions with
users
• Flash issues
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Long download for slow internet connection users
Need additional plug-in
Different version requires different plug-ins
Can’t accommodate large amount of text
Difficult/Impossible for visually impaired users to browse
Video for Web
• The largest multimedia element in size
• Low bandwidth video requires compression
– Choose the most commonly used compression
• Streaming Technology
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Data ‘streams’ from the server to the player
The player commences playing while data is still streaming
Audio streaming uses a buffer
Video streaming uses a bigger buffer
Example : www.youtube.com
Good and Bad Websites
• http://www.coolhomepages.com/
• http://www.webpagesthatsuck.com/
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Good or Bad?
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