A Technical View: Streaming Web Video
I first came across the idea of using streaming video technology in the delivery
of course materials in the January 1999 Syllabus magazine. In an article in
that issue, Lawrence Hinman, a professor of philosophy at the University of
San Diego, compared non-streaming and streaming video technologies and described
the steps to putting video on the Web. Since then, Ive learned from my
own experiences incorporating streaming Web video in chemistry classes at Ohio
Video files are usually several megabytes in size and consequently take a long
time to download. A non-streaming video file has to be downloaded in its entirety
before it begins to play. In streaming video technology, the program downloads
the beginning of the file, forms a buffer of packets, and when an appropriate
buffer is reached, the client player plays back the packets in a seamless stream.
While the viewer is watching, the next portion is downloaded, until the entire
file is played without any interruption. Streaming media can include audio,
video, animation, and scrolling text.
Producing both live and streaming video require the same equipment: a video
camera (analog or digital), video capture card, a video editing program, video
encoding technology, a computer with plenty of storage to act as a server, and
a high-speed network connection.
In a typical chemistry class, it is often difficult to teach students the correct
use of an apparatus and safety precautions for handling chemicals and equipment
before they perform an experiment. They also need to have a clear understanding
of chemical reactions and how to handle them. Some students may be capable of
grasping these concepts by reading a printed lab manual, but most students now
learn more through visual aids.
At Ohio University Eastern campus, we have tried to incorporate all of these
factors in producing video clips of chemistry experiments for students to view
before they actually carry out the experiments. And, for the last two years
our freshman chemistry students themselves have been involved in the production
of video clips of chemistry experiments.
While commercially produced videos of chemistry experiments are available,
we believe that students can absorb and relate better to demonstrations they
produce themselves. In this case, the students researched the topics and wrote
outlines. They also demonstrated the techniques of each experiment and provided
the narrative. Then videos that were shot were edited, compressed, and several
video clips of each experiment were produced.
We bought a license for RealServer software to stream the videos on to the
World Wide Web. The video clips are now available at the course Web site for
students to view before they come to the laboratory. Computers are also available
in the laboratory for students to review all or parts of the video clips while
they do the experiment.
When we decided to investigate streaming audio and video, we examined several
formats that were available, including RealNetworks, Windows Streaming, and
QuickTime. We settled on the Real format because it has good compression while
still maintaining good sound and video quality. Reals cross-platform capabilities
have also been important to us. The Web was designed to be accessible no matter
what computer operating system one might be usingWindows, Linux, Macintosh,
BeOS, or DOS.
The RealPlayer is available, for free, for most of these operating systems,
so we can be reasonably sure that our students will be able to access the audio
and video clips even if they use older computer systems. Our campus is located
in a rural area and many of our students cant afford the newest, whiz-bang
computers. Also, the Real format can include compression back to RealVideo 5
(they are now at version 8), so that older computers can still view our clips.
Our RealServer is running on a 600Mhz Gateway 7210 server with 512M of RAM,
and 2 two hard drives: a 15G drive that contains the operating system files
and a 8G SCSI drive for the Real audio and video clips. As additional space
is needed to store the audio and video clips, we can add additional drives to
the SCSI chain. The server is running RedHat Linux 6.2 as its operating system.
We have had very few problems with it. As of now, the Real server has been running
continuously for almost three months without requiring a reboot.
We are currently feeding our clips out over a T1 (1.5 Mbs) connection and so
far, we havent experienced problems with network congestion because of
the streaming video. But as more faculty and students start using the RealServer,
network congestion will become an issueand my next challenge.