A successful videoconference requires a number of elements in place. The local environment—the room, lighting and PA—have a tremendous influence on the reception of the content. Transmission link parameters affect both the quality of the transmitted video and audio signals and of the content received from the other party.
NASK specialists will help you to evaluate the location with regard to videoconferencing requirements and to verify or provide transmission links. A few tips:
- Lighting: during a videoconference, the screen should be in a shadowed part of the room, so that not much light is cast on it. The lighting should not be inconvenient to the videoconference participants, but at the same time it should provide adequate lighting conditions for the camcorder. The rule of thumb is: a dark area around the screen and quite a lot of light in the room.
- PA: the room should have equipment that provides sufficient volume and ways to control it during a videoconference. If more than one microphone will be used, a sound engineer is necessary. A sound engineer controls the volume level in the room by balancing the audio volume from the local microphones and from the incoming audio signal. Otherwise, an echo effect can occur between the videoconferencing parties that will render the videoconference impossible to hold.
- Connection: the video terminals used by the parties can communicate using ISDN or IP links, including a satellite connection. ISDN offers the best quality by providing a sufficient bandwidth and very small signal delays. IP connections over the Internet offer a very good quality and lower costs. However, ensuring correct end-to-end parameters (between both videoconference parties, via all the intermediate devices) always comes with a risk. Using satellite links—mainly because of their very high cost—is only recommended in locations where other connection types are unavailable. The table below presents a comparison of price and quality parameters for the different connection types:
| |
ISDN |
IP |
Satellite links |
| Quality |
Best |
Very good |
Acceptable* |
| Price |
High |
Low |
Very high |
| Optimum data rate |
384 kbps |
1 Mbps |
512 kbps (up) 512 kbps (down) |
| |
 |
* one-way delay is about 1 s
|
