The quality of videoconferencing is getting better and better all the time! Still, compressed video does behave differently than the TV-quality broadcast video to which most of us are accustomed. Video compression algorithms rely on the assumption that there are usually only small changes from one "frame" to the next. You can see where trouble might occur when you have an entire class of squirming students or even the natural movements of a solitary adult in a wildly patterned outfit.
In addition to the technical constraints, the politics of interaction are somewhat altered during a videoconfernce. Understanding these technological constraints and working with the human
factors can greatly improve a videoconference. Once you are past these initial barriers, the technology fades away and the personal interaction between participants begins. For more practical tips for interacting over video, see our Communication tips.
Working With Technological Constraints Transmission of compressed video is done via a smaller "pipe" than a televised broadcast. The camera and microphone take in more information than the "pipe" can handle. Outgoing video and audio information must be processed by a piece of equipment called the codec (coder-decoder) before it can be transmitted. Incoming signals are then decoded before they are sent to the monitor and speakers. All this processing takes its toll on the resulting picture and sound, and can result in the following:
Video "ghosting" or "pixilation" is the codec's way of compensating for rapid information flow. One way the codec compacts information is by reducing frame rate (number of video images per second), which can make rapid motions appear jerky. The codec also drops resolution to compress information, as in the photo shown, which can make an image fuzzy or chunky. To reduce these effects, reduce the amount of change. Avoid rapid motion, wear plain clothing, and hang a pastel curtain behind participants to reduce extraneous visual information.
Audio delays can occur because it takes a little longer for information to compress, travel, and decompress. Videoconferencing novices usually experience a few awkward conversations due to this time delay. Since there's no way to prevent the delay, learn to finish thoughts in a single statement with an obvious conclusion. Listeners should avoid interrupting and use visual cues (like nodding) instead of verbal affirmations (like "uh huh").
Oh yes, let's not forget that it takes a little while for the video call to "hangup." Just because you pressed the button to end the call doesn't mean that the other end has instantly disconnected. Be careful what you say until the call has completely disconnected!
Audio "clipping" or echo might take place if your audio system isn't properly configured. If you are experiencing audio problems, reset the echo canceler (if you have one) and reduce background noise. You should also check your equipment documentation
for volume and microphone placement guidelines. Depending on equipment, use of headsets and external speakers can also improve audio quality.
For more information on video compression, try these pages:
From Colin E. Manning, What is compression? Part of a presentation on digital compression.
Check out the Videoconference Zone from University of Washington for a streamed video "The Videoconference Zone" about common pit falls and how to avoid them.
Working With Human Factors
Another part of understanding two-way compressed video is understanding how it is perceived by users and how these perceptions influence interaction. Try to keep the following human factors in mind as you explore two-way video.
Videoconferencing etiquette must be established immediately by the users. Most people have not experienced videoconferencing and do not communicate as they would in a face-to-face situation. For example, in the middle of a carefully prepared demonstration, a remote viewer breaks into conversation, interrupting and ignoring the designer. Would this happen in a local demonstration? Probably not. One of the best examples of "video rudeness" we've ever heard of involved a meeting in which one of the remote participants did not want to attend. They focused the camera on the floor and left the room without saying anything!
Shuffling papers or dangly bracelets in constant motion near the microphone, entering or leaving during a meeting, even serving food and drinks can be extremely disruptive. By muting and switching camera positions, you can mask these activities and eliminate interruptions for the remote sites.
Unfortunately, we're just not accustomed to conversing with a television image, and two-way video etiquette has yet to be ingrained.The groundrules of your videoconference should be made clear at the onset. Better yet, a hard copy of the agenda and groundrules can be sent ahead of time. Here is a real example of groundrules for students taking courses at the
University of Wisconsin-Milwaukee and a good overview of all aspects of delivering video content including Site Roles and Responsibilities from EduTech (cached on Internet.org). See also the Utah Education Network which provides very specific guidance for the Site Facilitator.
Examples of simple groundrules you might set are:
mute your audio unless you are speaking
introduce all members/speakers
arrive early - arriving late is even more disruptive than a regular in-person situation
decide how questions/interruptions will be handled (during or after presentations)
rotate thru to remote sites in a particular order for questions
continuously include the remote end, don't turn your back or start side conversations
if you are demonstrating something locally, put it on a document camera afterwards so that other sites can see it
repeat questions so that all participants can hear them
send in questions ahead of time and have a facilitator handle questions, or use fax, phone, email, or IM/chat
Two-way videoconferencing
is unlike one-way television, but many people have a difficult time changing habits and preconceptions produced by years of experience with television. Not only do we tend to "tune out" what's on a television screen; we also expect to be entertained by it. We expect broadcast quality video, slick graphics, and a quick pace to keep us engaged. And if we're not fascinated, we quickly change channels to something more interesting. The behaviors we associate with television -- channel surfing, "spacing out" -- are not optimal learner behaviors. Teachers who use two-way video must challenge basic learner preconceptions and set new expectations to maximize learning. Fortunately, good classroom instructional strategies are also good two-way video instructional strategies! See our section on Instructional Strategies for specifics. Here are a series of hilarious, yet perfect movies from the University of Washington that demonstrate some of the challenges you'll face as you move from simple videoconferencing to full-scale production. Although some are geared for broadcast TV, you can see the similarities.
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Where has all our content gone? KNE has been on the Internet since 1995. Support has changed. We will continue to host Filamentality and several of our original sites including Videoconferencing for Learning, Filamantality, and the Big6.
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First posted 1995.
Last modified
Monday October 05, 2009
