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Volume 2 Issue 4April 1998

Using Compressed Video for Distance Learning (Part One of Two)

Jodi Reed, M.A.
Pacific Bell Education First Fellow

Merry Woodruff, M.A.
Consultant

(Reprinted with permission from Magna Publications)

In the past, distance learning with two-way video was out of reach for many institutions. Recent innovations in telecommunications technologies such as ISDN and compressed videoconferencing systems have lowered equipment and transmission costs, making two-way video feasible for small colleges, businesses, classrooms, libraries, and even homes. Unfortunately, access to the latest videoconferencing technology does not guarantee a valuable learning exchange.

While compressed video holds great promise for expanding the classroom experience, it also amplifies poor teaching styles and strategies. With this in mind, instructors considering use of compressed video will need to understand and work with the advantages and constraints of the medium to ensure a quality telelearning experience. In particular, instructors should plan to devote greater than normal effort toward preparation and development of instructional strategies that actively engage learners. The planning process and learning curve may seem excessive at first, but the shift from "knowledge disseminator" to "learning facilitator" is likely to enhance learning for both local and remote students. This article provides a path for instructors to develop and implement effective telelessons that employ the potential of two-way compressed video.

Advantages of Interactive Videoconferencing
Establishes a visual connection among participants. Since a teacher can see and hear remote learners in real time, he can use conversation and body language to enhance communication. Frequent interaction increases understanding and encourages more personalized instruction. Interactive teaching strategies such as questioning and discussion can also help engage and motivate learners by making them active participants.

Enables connection with external resources. Remote experts can help validate understanding, provide feedback, and introduce practical examples. This real-world connection can greatly improve motivation, especially if students participate and the expert interacts at an appropriate level.

Supports use of diverse media. Photos and color graphics look great on video and can help convey a difficult concept or simplify instructions. Room-based systems usually include an attachable document camera that allows transmission of a high-quality still image. This feature can be used to show objects as well as photos and graphics, and many instructors also project "slates"--simple text displays with a few sentences (usually instructions). Slates are an easy way to shift learner focus from the video screen to a learning activity.

Document sharing facilitates collaboration and feedback. Some systems allow application sharing, allowing users at each site to see and edit a document. This kind of sharing encourages collaboration and real-time feedback.

Working With Technological Constraints
Compressed video behaves differently than the video most of us are accustomed to. Understanding and working with these differences can help improve a videoconference. In general, compressed video must transmit information via a smaller "pipe" than a televised broadcast. The camera and microphone take in more information than the "pipe" can handle, so the 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 decoded by the codec before they are sent to the monitor and speakers. All this processing takes its toll on the resulting picture and sound, and usually results in some of the following features.

Video "ghosting" or "image softness" 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, which can make an image fuzzy or chunky. To reduce these effects, reduce the amount of visual information flux. 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 about a second for information to compress, travel, and decompress. Videoconferencing novices usually experience a few awkward crossed "go ahead" 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").

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.

Working With Human Factors
Another part of understanding two-way compressed video is understanding how it is perceived by its users and how these perceptions influence interaction within this medium. Try to keep the following human factors in mind as you explore telelearning via two-way video.

Videoconferencing etiquette must be established by the users. Most people have not experienced videoconferencing and do not communicate as they would in a face-to-face situation. Two-way videoconferencing is unlike one-way television, but many people have a difficult time changing ingrained habits and preconceptions produced by years of experience with television. The behaviors we associate with television -- “channel surfing,” “spacing out,” “vegging” -- 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 two-way video instructional strategies are also good classroom instructional strategies.

(Part II will include Instructional Strategies, Planning a Lesson, Guidelines for Using Audio-Visual Aides, and Evaluation)