Disclosed is a method of transmitting video via a network and a user device and computer program product configured to implement the method. The method comprises transmitting video of one or more users, received from an image capture device, to at least another user device via the network; receiving information about a communication channel between the user device and the other user device and/or about one or more resources of the user device and/or the other user device; selecting characteristics from a plurality of visual user characteristics based on the received information; and controlling the video based on detection of the selected characteristics to track the selected characteristics.