One of the five crucial Webcast questions I discussed in last week’s New Media Roundtable column was “How concerned should I be about the actual production of my Webcast?” The answer I gleaned from the advice of several Webcast professionals was that the IT team can’t afford to ignore production issues. Camera positioning, sound, and lighting can seriously affect the quality of a Webcast, and if these elements take a backseat, it’s likely that the technology team will get the blame for the resulting inferior production.
This week, I’m going to share with you some more in-depth advice on the subject of Webcast production, courtesy of Gartner analyst Lou Latham. (TechRepublic is an independent subsidiary of Gartner.) In the following Research Note, Latham examines the importance that sound and lighting play—both aesthetically and technically—in creating a successful videoconference, and he shows how a moderate investment in these elements can pay off many times over. His advice, of course, applies to Webcasts as well.
To read the full Research Note, click here. If you have any reactions to Latham's thoughts, you can post them in the Discussions area at the bottom of the page.
Be sure to pull up a chair at the New Media Roundtable next week, as our monthlong coverage of "Planning and Implementing a Webcast" continues with an interview with two members of the Yahoo! Broadcast engineering team. These experts will provide answers to Webcast questions submitted by TechRepublic members. The following week, I’ll look at the Webcast lessons learned by a real IT department in our featured case study.
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Videoconferencing venues: Light and sound are critical
By Lou Latham
When planning a group videoconferencing installation, enterprises should pay close attention—and a piece of the budget—to the quality of lighting and acoustics in the room where conferences will take place.
Enterprises planning a videoconferencing facility need to budget for several things in addition to the equipment itself. One expense that is often overlooked is the preparation of the room for videoconferencing use. While it is important that the room be comfortable, the two most significant considerations are the quality of the sound and the lighting. Of the two, acoustics is the most important.
The value of sound
Sound quality is the most important factor in a videoconference because it generally carries the most information. Echoes or blurry sound can become extremely annoying and consume unacceptable amounts of cognitive effort on the part of the participants, thus reducing the effectiveness of the collaboration. (In the context of this discussion, “echo” refers to room reverberation rather than the end-to-end feedback that is commonly dealt with by echo-cancellation software in the system.)
The other two reasons for the importance of sound quality are technical. First, while sound occupies a relatively small percentage of the bandwidth in a conference, the resources required to compress and transmit it can affect the video as well—particularly if the total bandwidth is limited—because the system is designed to prioritize for sound quality. Second, bad sound, particularly reverberation, can confuse the automatic tracking mechanism that allows many cameras to pan and focus on the person speaking. In the extreme, the camera can end up pointing at an empty spot in the room, sending a useless picture to viewers.
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Room echo or reverberation affects compression and bandwidth because it increases the total amount of information that the compression system has to process. The system has no way of discerning the difference between an echo and any other sound, so in essence, the echo doubles the amount of audio data entering the system. The extra information increases latency and drives up the bandwidth required for audio. It can starve out video information and reduce the frame rate, producing a jumpy picture if bandwidth is limited.
To combat these disruptions, facility planners should take all possible steps to eliminate hard surfaces from the room by installing foam- or fabric-based wall coverings, high-absorption ceiling tiles, and heavy rugs. If a contractor is engaged for the installation, the work should be included in the request for proposal and the contractor’s knowledge of this issue should be a selection criterion. The contractor should echo-test the room with “pink” noise after completing the acoustic treatment to ensure its efficacy. If a room is being constructed explicitly for this purpose, the treatment can be enhanced by making facing walls slightly nonparallel, which will prevent standing waves.
The value of light
Lighting quality, while less critical than sound quality, is important for some of the same reasons. One is aesthetic: A muddy, flat, or jittery picture is not as likely to obscure significant information as a bad soundtrack, but it diminishes the conferencing experience substantially. In some circumstances, such as negotiations, the picture can convey psychological cues or other information that is valuable to the participants.
The disruptive video factors are similar to those of audio. A “busy” picture, like a noisy soundtrack, adds extraneous content to the data stream, which steals bandwidth and taxes compression systems. The solution is also similar: Design the lighting and layout of the room to minimize the disruptive elements. These include glare, deep shadows, high-contrast and hard edges, complex backgrounds caused by deep focus, and unnecessary motion in the frame. Ugly or unnatural colors can also be an aesthetic problem.
These problems can be abated by correctly selecting and positioning the room lighting and the camera. Very high light levels are not required; a normal office light level is sufficient. However, incandescent lighting should be used rather than fluorescent; it is more controllable and renders colors (particularly flesh tones) more accurately and attractively. Down-lights should be avoided; they create deep shadows under the eyes. To improve light distribution, ceilings should be a light, neutral color. Reflective fixtures that spread light over the ceiling and across the walls will ensure that at least one-third of the light strikes the participants’ faces from the side to prevent unattractive shadows. To reduce hard edges, the light should come from several directions and be low in contrast (no more than 3:1 or one and one-half f-stops) but not so flat as to blur facial details that transmit expression. To separate faces from the background, some light should come from behind the participants, but the fixtures should be well out of camera view.
Clean, simple backgrounds will help to reduce compression and bandwidth load by eliminating unnecessary detail. Walls in camera view should be matte in finish, neither white nor extremely dark, but slightly (one stop) darker than skin tone and free of busy detail. Ideally, the room should be large enough to throw the background out of focus, further reducing detail that must be compressed.
To reduce clutter and also reduce movement on-screen, which places heavy demands on compression systems, rooms should be arranged so that doors, windows, and traffic paths should be out of camera view. In particular, bright highlights such as windows and light fixtures should be kept out of camera view, since the exposure system will compensate by unacceptably darkening the foreground.
A small investment in optimizing the ambiance of a videoconferencing room (e.g., $10,000 to $15,000) will go a long way toward reducing bandwidth and compressor stress and make videoconferencing a positive experience for the participants at both ends.
Gartner originally published this report on Nov. 14, 2000.