If static graphics and text aren't enough to present your message on the
Web, you can add multimedia elements as well. Providing that your readers
have the right hardware, software, and Web connection, you can offer them
Web pages with sound, animation, and even approximations of
television-style video.
However, you should consider carefully the technical profile of your
audience before you add such elements. Each brand of browser
supports only some types of multimedia. Performance of multimedia elements
also depends on the type of connection and the network load. Users who sign
on to the Web using one of the large commercial services such as America
Online or CompuServe may not be able to use any of these multimedia
features at all. Many machines, especially those in business, lack
sound-output capability. Some surveys say up to 25 percent of Web users are
either using character-based terminals or turning graphics off for greater
speed. If you decide to go ahead, you'll have to decide from among dozens
of different software packages and approaches.
If simple "page-flip" style animation is enough--that is, animation made by
showing a series of similar images in sequence--you may be able to get by,
just by creating the right kind of graphics files. As explained in
exquisite detail at GIF Animation on the WWW, the GIF89a standard allows one
file to contain a full set of images plus a value for the interval between
the showing of successive pictures. Almost all browsers now support this
feature, but you may need to switch to one of the programs listed there to
produce the appropriate files.
With a little bit more trouble, you can have the server send
sequences of images to the browser or have the browser ask for new images
at short intervals. For details, check Netscape's Exploration of Dynamic Documents. Besides
taking a bit more programming, this server push and client pull
can respectively load up your connection and annoy users who don't want you
taking control of their browser.
If you need more complex media types, such as coordinated sound and images,
it's usually easiest to use a packaged multimedia product, such as Macromedia Director, equipped for Web output. You design
your elements as normal multimedia objects, then output them in a special
Web format. Your multimedia files are then downloaded to viewers of
your page by the server, much as it would send out static images.
In most cases, however, viewers of your page will have to add a
corresponding plug-in--in this Macromedia Director example, the
Shockwave plug-in--so the browser knows how to present the received
data. Check the complete guide to Netscape-compatible plug-ins. For
Microsoft's view, see the company's plug-in page.
While playback plug-ins are usually free, some authoring packages command
hefty prices. And for such techniques as audio and video that send a
real-time stream of data from server to user, you'll probably have to
license a special server program or buy an add-on server hardware module.
Another possibility is to use the multimedia capabilities in the Java language, since Java playback capability is included in most newer
browsers. If you want to concentrate on users with Microsoft's Internet
Explorer, you can alternatively use that firm's similar ActiveX
technology. Code hackers can write Java code or ActiveX scripts directly,
but most of us might want to first check out the list for Java tools and ActiveX tools.
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