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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 the lecture!

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 suit.

What is Required to Play Streaming Media?

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 school.

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 more bandwidth.

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 File?

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 quality.

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 a Course

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.




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