ITSS WebDev Guide
Using multimedia on the web
Multimedia (audio and video) allows many possibilities. Audio and video may be delivered separately or together. Let's take a look at some examples:
This is a QuickTime movie of Hurricane Guillermo from NASA's Multimedia Gallery. I'll be using QuickTime for all the
multimedia examples. This movie is video only and shows the counter-clockwise rotation
of the storm. To see the video, click on the picture of the hurricane. You'll get one of three versions tailored-made for your
connection speed.
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When doing a multimedia presentation, be sure to include a text description of the event. This way, users with
non-graphical browsers or text-to-speech converters will still receive the content.
In the movie above you'll see a text description of the hurricane. The text was converted into a movie from
the document prepared by NOAA.
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Audio may be added along to the video as in the movie to the right. The audio can describe the video event (which
is helpful to aural learners) and/or it may be something to enhance the video such as music. Multiple video and
audio tracks are possible. I only made one version of this movie.
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The original size of the hurricane file (video only) is 3.1 MB and has a data rate of 716.2 k/sec. The compressed version for Web delivery is 24.6 KB and has a data rate of 5.4 k/sec. The compressed version is also smaller in viewable size, but it will start playing before it has finished downloading on a 56 kbps modem.
Where to go from here?
Deciding on how to handle multimedia for Web delivery can be quite a challenge. Audio and video put many demands on bandwidth and computer resources. To make matters worse, the technology to create, edit and deliver multimedia changes rapidly.
Consider your intended audience as you would with any other Web page. If you're trying to reach users on Macs and PCs, look for cross-platform solutions such as QuickTime, Real, or Windows Media. Other choices are available and may meet your needs. Be aware that great looking video on your computer may not look so great on older hardware. I know these hurricanes won't look as neat on slower machines, but they still work.
Audio may be played back on killer multimedia speakers with subwoofer or it may come out of the cheap, little speaker on the computer. Make sure it is intelligible regardless of where it is played back. Spend some time editing the audio with an audio editor. This kind of software will allow tweaking of the audio to get it right.
Links
Rev: bdr 07.06