A method of controlling a video source in a video surveillance system having a video source connected by a network to a workstation having a graphical user interface for enabling a user to control the video source comprising the steps of providing a video analysis program for analyzing the video images generated by the video source before the video images are transmitted over the network, providing a file containing the user interface controls for the graphical user interface and the parameters for configuring the video analysis program; storing the file in memory, downloading the file to the workstation at run time and enabling a user to configure the video analysis program by interacting with the graphical user interface.