CSci 220 - Lecture 18
Web Page Design
© Morris Firebaugh
Multimedia on the Web
A. Multimedia Concepts and the WWW Environment
Multimedia is the "emerging technology"
- Starting point has been the written word (Text, symbols)
- Next, images and graphics were added (static, but visual)
- Then came moving images (animations and video)
- Sound (both voice and music) may be associated or standalone
- Early multimedia entertainment experiments (Morton Heilig's Sensorama) even included smell
- The ultimate media is virtual reality
Notice the pattern
- Communication is more effective the more senses involved
- The visual sense has the highest "bandwidth" and information content
Evolution of the Technology
- Early multimedia delivery was through expensive "kiosks"
- CD-ROM + powerful PCs are extremely effective multimedia platforms
- However, the WWW + powerful PCs are emerging as the most effective MM tool
- Personal PCs are now completely MM capable
- The WWW has potential as a vast MM source
- The weak link, Modem bandwidth, is being overcome
Browsers typically play multimedia using "plug-ins"
- Netscape 4.7 list 70 "applications" mostly done by plug-ins
- Plug-ins are small programs which Netscape (or IE) calls to interpret or play MM files
- One can think of plugins as MM extensions
B. Audio on the Web
Audio file types include
- WAVE Audio
- AIFF Audio
- ULAW Audio
- QuickTime Audio MPEG
- MP3 Streaming Audio
Two General Classifications include
- Nonstreaming (Static) Audio
- Streaming Audio
Basic Digital Audio Concepts
- Sampling Rate (8 KHz, 11 KHz, 22 KHz, & 44 KHz)
- Bit Depth (8 & 16)
- Channels (Monaural, Stereo, 3, 4, & 6 channel "surround sound")
- Compression (MPEG, AIFF/C, MP3)
Three modes for embedding audio files in your HTML document:
1. Simple anchor and href:
<a href="Laugh.AIFF">Silly Laugh</a>
2. Use of the <EMBED> tag
<embed src="DELIUS.MOV" width="128" height="20" autostart="true">
3. Linking to a sound file on the WWW
<a href="http://chooser.mp3.com/cgi-bin/play/play.cgi/AAICQiG0BADABG5vcm1QAwAAAFLIBAAAUQIAAABDcm7WOPHjONUoB4ZpzbKbKCT384c-/lord_of_the_dance.m3u">Lord of the Dance</a>
Lord of the Dance
SoundEffects can help you process sound files:
C. Video on the Web - QuickTime Movies
The HTML Syntax for embedding a standard quicktime movie is:
<A HREF="Bear.mov">QuickTime Movie</A>
The QuickTime Movie file, Camel, is linked by:
1. Link is identical to that of any other URL
2. When clicked, browser calls up appropriate Plug-in (QuickTime) to play it
3. This leaves an awkward open Quicktime window when completed.
The QuickTime Movie player can be embedded to give better control:
is produced by the code:
<embed src="Golly.mov" width="160" height="136" align="bottom" type="video/quicktime" autoplay="false" controller="true" cache="true">
Other attributes of <EMBED>
- HIDDEN (for sound-only)
- HREF="filename" (provides link to another page when movie is clicked)
- TARGET="frame" (specifies frame to be target of link)
QuickTime Movies can carry a strong advertising wallop:
D. Virtual Reality on the Web
- A thorough background reading list in Virtual Reality has been compiled by Toni Emerson, the Research Librarian of the Human Interface Technology Lab of the University of Washington.
- Virtual Reality comes in two modes:
- Images of Real Scenes which you can explore (QTVR)
- Mathematical Models of Virtual Scenes which you can explore (VRML)
- An interesting set of QTVR scenes is contained on the 2 CD-ROM Mars Rover collection.
- These are in the QTVR format
- Must have downloaded QuickTime
- They represent actual radar images of the Martian surface
- This example illustrates the first QTVR mode: 360 o panorama with zoom
- Second example is the Object Rotation Mode
A good survey of VRML Virtual Reality projects is presented by the IML Lab of Millersville University
E. QTVR Protocol
- The Apple "QuickTime" URL demonstrates the potential of this technology
- The nagivational syntax is simple and transparent
- <Option> to zoom in
- <Control> to zoom out
- Cursor position w.r.t. the screen center to
F. VRML Protocol
- VRML was conceived in the spring of 1994 at the first annual World Wide Web Conference in Geneva, Switzerland. Tim Berners-Lee and Dave Raggett organized a Birds-of-a-Feather (BOF) session to discuss Virtual Reality interfaces to the World Wide Web. Several BOF attendees described projects already underway to build three dimensional graphical visualization tools which interoperate with the Web. Attendees agreed on the need for these tools to have a common language for specifying 3D scene description and WWW hyperlinks -- an analog of HTML for virtual reality.
- The term Virtual Reality Markup Language (VRML) was coined, and the group resolved to begin specification work after the conference. The word 'Markup' was later changed to 'Modeling' to reflect the graphical nature of VRML. Shortly after the Geneva BOF session, the www-vrml mailing list was created to discuss the development of a specification for the first version of VRML. The response to the list invitation was overwhelming: within a week, there were over a thousand members. After an initial settling-in period, list moderator Mark Pesce of Labyrinth Group announced his intention to have a draft version of the specification ready by the WWW Fall 1994 conference, a mere five months away.
- There was general agreement on the list that, while this schedule was aggressive, it was achievable provided that the requirements for the first version were not too ambitious and that VRML could be adapted from an existing solution. The list quickly agreed upon a set of requirements for the first version, and began a search for technologies which could be adapted to fit the needs of VRML. The search for existing technologies turned up a several worthwhile candidates. After much deliberation the list came to a consensus: the Open Inventor ASCII File Format from Silicon Graphics, Inc.
- The primary inovation has been from Silicon Graphics, working with NetScape, to produce the standard known as "Moving Worlds", a.k.a. VRML 2.0
Example 1: Temple.wrl
- Let's see if we can link to it and wander through it.
1. VRML Models do not have the realism of QTVR photos
2. VRML Models allow you to "walk through" them, wander at will
3. VRML Models typically consume less space than QTVR images.
G. Virtual Reality Design Tools
- How are QuickTime VR Movies made?
- Our best Design tool is Virtus WalkThrough
Revised March 13, 2001