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Points to consider when integrating audio
and video streams into your course web site:
- Always remember bandwidth limitations. You will likely
need to make compromises in audio and video quality. If your students
are connected to a LAN, then streaming audio and even streaming
video is very feasible. However, when trying to send motion video
to students with modems, do not expect video quality to be very
good, and in many cases, it is just not worth it. However, when
motion is not essential, and if you need both visuals and audio
to convey the message, you should consider an illustrated audio
format. Several examples use this format quite successfully.
- Real media technology is the most widely used streaming media
technology on the Web right now with Microsoft’s NetShow
a distant second. NetShow works very similar to RealMedia requiring
a server and a player. Both these technologies are best used
when you have lengthy media clips and large numbers of students
hitting your Web site. However, there are other types of streaming
format such as Apple’s QuickTime, and Macromedia ShockWave.
- If you want to experiment with RealMedia technology, a sample
RealMedia Server can be downloaded for free from the RealMedia
Website.
In Conclusion....
Set the data rate of your movies slightly lower than the throughput
of your user's connection is you want them to be able to watch
your movies in real time. For a 28.8 modem that means a data rate
somewhere around two KBps, for ISDN around five KBps, and for T1
lines from five to 40 KBps. To deliver true video at these data
rates the compromises are great. The image size must be small,
the frame rate low, and the sound compressed. As a result of compression
the image quality will be less than optimal.
Nonetheless, there is still interesting video and sound that can
delivered using the web. If you are creating content for a web site,
tailor your multimedia elements for web delivery. Think of creative
solutions that may be more modest but will be viewable by your target
audience. For example, instead of using true full-motion digital
video and audio that will require so much compression and size reduction
as to render it useless, use audio and a sequence of still images
to add multimedia to your site. Say, for example, you want to use
video to show how to cook lasagna. Instead of using video, take a
bunch of still images and pair them with a good-quality narration
of the recipe.
If you must use true video in your site, be sure to shoot footage
that will handle the compression and size reduction required for
delivery on the web. Keep away from wide shots; shoot at medium
or close range so that the detail of the image will be distinguishable
at small sizes. The low frame rates and small viewing size required
for web video will not effectively display motion, so don't shoot
video that includes much action. The best source video for the
web is close-up shots of talking heads.
Pay attention to source. It is especially important that
web multimedia be created from excellent source. The processing that
must be applied to A/V elements in order to attain web resolution
will only emphasize any flaws in your original source. If you begin
with bad audio and then reduce its sample rate and depth, and then
add compression to further reduce the data rate, any flaws present
in the original source material will be exaggerated.
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