What is Streaming Media"?
Streaming media is delivery of continuous audio, video, and/or
text over the internet. The media is fed to the user as the media
is viewed. In other words, it's a continuous transaction. This is
very different from the typical "stateless" internet transactions
which require all data to be downloaded before the media file can
be accessed. Non-streaming files such as most .wav, .avi and .mov
files download completely to the client computer before they begin
to play. If the file is relatively long, as would be the case with
a lecture, the time to download might be the same as the length of
What Media Types Are Streamed?
Typically, audio files and video files are streamed, but new technology
from RealNetworks allows some image files, animations and text to
stream as well. QuickTime and Windows Media will be sure to follow
What is Required to Play Streaming
To play streaming media the browser on each client computer must
have a streaming media player. The players can be downloaded
free. If the streaming media contains sound (audio) then a sound
card and speakers are also necessary.
If the streaming media files to be played are on a server on the
Internet, then the client computer must also have an Internet connection,
either a dialup connection, or a permanent connection from work or
The Importance of Bandwidth
Bandwidth can be thought of as the size of the pipe through which
data that flows to your computer passes. The fatter the pipe, the
more data that can pass at one time. A fatter pipe corresponds to
If students are accessing your course page with a high bandwidth
line, they can see and hear high quality streaming media because
it passes easily through the big pipe.
However, if students are using a slow dialup connection, they may
be only able to see and hear streaming media that has been optomized
for their bandwidth.
When you create streaming media, you must assume that at least some
students will have a dialup connection. The streaming media you create
must be capable of passing through the small pipe. By necessity,
the quality of the streaming media will not be as good in order to
make the file size smaller.
What Happens When You Encode a Media
The media file you produce, either with a microphone or a cam corder
may be quite large. The larger the file, the more time it takes to
download over the Internet. So during the encoding process, some
of the information you recorded is thrown away to make the files
smaller. In addition, the file is compressed. The end result is a
streaming file that is considerably smaller than the original.
When media clips are encoded, you have some control over the amount
of information that is thrown away. The more information that is
thrown away, the smaller the file, but the poorer the audio and video
In general, the slower a student's Internet connection, the smaller
the file they need in order to experience streaming media.
When media clips are encoded into a streaming format, you can choose
the kind Internet connection to encode for. Since students may be
dialing from home and use a 28.8 kbps modem, you may want to encode
your file to play optimally at a speed of less than 28.8 kbps. You
may have other encoding options such as 56.6 or even faster. Some
instructors choose to encode their media clips using several different
Internet connection choices.
Remember that encoding for a slower connection produces a file that
is, in general, poorer in quality.
An Example of Streaming Media in
The Public Health
400 course at the University of Illinois at Chicago has a Real
Media clip of the instructor. Click the icon beneath Introductory
Video to see it. Notice that you have three choices that play different
clips, each optimized for a different bandwidth.