Introducing Interactive Multimedia

Internet & interactive multimedia

If you are reading this on the WWW, then it seems fair to assume that you have some knowledge of the Internet, at least to the level of being able to use it to access information. Similarly, if you completed Activity 1.1, then it seems reasonable to assume that you are capable of publishing simple pages on the WWW.

These are the base levels of skill you will need for working through these materials. However, there some other aspects of the WWW which may affect our work and which should be considered before moving forward.

Selected Reading 1.1

Kaplan, H. (1997). Interactive multimedia & the World Wide Web Educom Review 32(1): 48-52
<http://www.educause.edu/pub/er/review/reviewArticles/32148.html>
[27 Jun 2006].

Selected Reading 1.2

Lynch, P., & Horton, S. (2004). Web Style Guide (Multimedia) [URL: http://www.webstyleguide.com/multimedia/index.html [27 Jun 2006]

The first reading provides some context for thinking about strategies for developing educational multimedia materials for the World Wide Web. The second offers practical suggestions about designing multimedia for the WWW.

Internet basics and multimedia

Although the World Wide Web is just one of many services (others include electronic mail, newsgroups, telnet, FTP, IRC) which operate via the Internet, it is the most widely known and is regarded by many people as synonymous with the Internet. Rapid growth of the Internet has established its importance as a means of accessing information from multiple sources in a variety of formats.

From the point of view of multimedia, the most serious limitation of the World Wide Web is the limited bandwidth which restricts the volume of data which can be transmitted in the time available for viewing a screen of information. Text and compressed graphics present few problems but the more data rich dynamic content such as most digitised sound, complex animations and video, challenges the network capacity availalbe to many users. The following table provides some comparative figures for data transmission rates of various connections.

Connection type	Data rate (bits per second)	Time per 100 Kbytes
14k4 modem	>14 400	71 s
33k6 modem	33 600	30 s
56k modem	56 000	18 s
ISDN	56 000 to 128 000	18 s to 8 s
ADSL	256 000	4 s
2X CD-ROM	1 600 000	0.5 s
24X CD-ROM	28 800 000	0.02 s

Consider, for example, the 33k6 modem connection. We are able to transmit 33600 bits per second. There are 8 bits in a byte, though the need to separate bytes in a stream of data usually results in a byte requiring 10 bits rather than 8 to be transmitted. Assuming, for the purpose of calculation, that 10 bits are required, 100 Kbytes comprises 8 X 102 400 = 819200 bits but will require 1 024 000 bits to be transmitted. Thus the time required will be 1 024 000 bits / 33600 bits p s = 30.5 s.

It is clear that compared to transferring data from a local device such as a CD-ROM, Internet connections may be relatively slow. Designers of multimedia for use across the Internet need to be aware of the limitations of bandwidth from the beginning of planning through to final delivery. We will be attending to these issues as we deal with the various elements of multimedia.

Activity 1.2

This activity has two simple calculations in which you can check your understanding of some factors affecting responsiveness on the WWW.

Tools for the World Wide Web

Servers

You will probably never need to operate your own web server in order to publish on the WWW. Instead you will use server facilities provided by an employer, Internet Service Provider (ISP), educational institution or other source. Such services provide simple but effective means of uploading the files needed to build a web site with media components such as we will be using in this course.

Installing and managing a web server system for a busy site is a major undertaking which usually requires a team of well trained specialists. On the other hand, current versions of operating systems such as Windows and MacOS include software for personal web serving. Getting it running can be as simple as switching on the server software and indicating which directory has the files for the web site but the fact that it is simple does not mean that it should be done unthinkingly. Running a web server on a personal computer without a network connection can be useful for building understanding of how web servers function and for testing the operation of dynamic, database driven sites using techniques such as ASP or PHP. If the computer is connected to a network, especially to the Internet, then it is important that you take proper precautions to safeguard it against attack. Since it is unlikely that you will need to make a web server on your personal computer available on the Internet, your best precaution is ensure that, if you ever activate the web server, you do so only when you are not connected to the Internet and disable it before you reconnect to the network.

Browsers

The best known web browser is Microsoft Internet Explorer because it is enabled by default on the vast majority of personal computers. However, there are other web browsers available for Microsoft Windows and other operating systems such as MacOS and Linux. Unless you know for certain that all your users will be using a particular browser version, you should design web content to comply with relevant standards developed by groups such as the World Wide Web Consortium (W3C).

Unfortunately, in their efforts to enhance the content delivered in the browser, software developers sometimes step ahead of official standards. Worse, for developers of web content, the browsers have diverging standards in some areas and material which works on one will fail on another. It is probably safest to avoid the latest fads and it is always prudent to test on as many different systems as possible. One option for testing the compatibility of your site is to use the service provided at AnyBrowser.com.

Editors

Because web pages are fundamentally plain text files, it is possible to develop sophisticated web pages using nothing more complex than NotePad with Windows or an equivalent program on another system. At the other extreme there are WYSIWYG (What You See Is What You Get) editors for web pages that shield the designer from the internals of the page code and permit concentration on content and layout.

Most web editors are available in trial versions which will allow you to test them in use before committing to purchase. The HTML Editorspage at Yahoo has links to sites where you can find reviews of editors or download software. Although I have preferred tools, mostly DreamWeaver, I have yet to find one that does everything as I would prefer. I tend to change tools according to the task at hand.

If you are using a WYSIWYG web editor take care to avoid using features that are peculiar to that particular editor and may not be supported by all servers or browsers. Microsoft FrontPage is one popular editor which offers a range of features (extensions) which some people find useful or attractive but which are not supported by all browsers or which require the server to be set up in a particular way. If you do decide to use FrontPage be careful that any work you present for assessment is restricted to standard HTML and does not depend upon features peculiar to FrontPage.

Plugins

Plugins are small programs which extend the ability of a web browser to display different forms of multimedia content. As is evident from plugins.com, there is an array of plugins for different purposes. The Netscape plugin architecture used <EMBED> tags in HTML. It is now deprecated by the W3C in favour of the more general <OBJECT> tags.

As an author you cannot assume that users will have a particular plugin or be prepared to download and install it. Certain plugins are commonly available and QuickTime and Flash players are widely distributed and installed. Other plugins may offer sufficiently compelling reasons to encourage their use but be aware that, unless you have a captive audience, any content that requires additional software may be ignored by some users.

There's still more

Other ways of enlivening web pages include the use of Java and JavaScript. Java is a complete programming language which may be used to build powerful applications as well as the smaller applets that are inserted into web pages. JavaScript is a much more limited language which can be used to control the behaviour of elements in a web page.

Designing for the World Wide Web

The mixture of at least text and graphics in the World Wide Web with a point and click interface to numerous choices makes the Web an inherently multimedia experience.

There would seem to be at least two reasons for including media elements other than text and graphics in a web site:

The addition of media adds interest or functionality to the site.
A web site provides a convenient and effective means of distribution for media content.

Most of the factors which contribute to good design in print or in multimedia for delivery other than on the web also apply to design for the web.

As noted above, the major additional constraint is bandwidth. Or more accurately the lack of bandwidth for transmitting large volumes of data.