How does video streaming work?
In order to play smoothly, video data needs to be available continuously and in the proper sequence without interruption. Until fairly recently, video had to be downloaded in its entirety to the computer before it could be played. With streaming, the file remains on the server. The initial part is copied to a buffer on the computer and then, after a short delay, starts to play and continues as the rest of the file is being pulled down. Streaming provides a steady method of delivery controlled by interaction between the computer and the server. The server regulates the stream according to network congestion and thereby optimises the presentation on the students computer.

Educational possibilities and problems

From a learning and teaching perspective, the challenge for academics is how to use these new technologies in ways that are pedagogically appropriate and sensitive to their students needs and the learning context. The choices with video streaming are intrinsically different from those of earlier video technologies. The main choice for developers at the moment is the crucial compromise between image quality and accessibility to remote users. On internal university and college networks and for users with broadband (high speed) connections, high quality full motion video can be delivered effectively, albeit usually in a small window.In these circumstances video streaming can fulfil at least the same role as conventionalvideo tapes, the advantage of course being in distribution and flexibility.

from : www2.umist.ac.uk