There exist a number of algorithms for compressing digital video, such as the ISDN H.261 standard, and MPEG I and II. With all these algorithms, it is possible to vary the degree of compression within the codec and thus the output data rate, by manipulating the parameters of the algorithm. Using intelligent codec implementations, it becomes possible to send compressed video over packet switched networks and adapt the rates at which the compressed video is produced to maximise video quality, whilst protecting the network from congestion. This thesis presents two viable schemes which use results from human factors experiments that prove this is possible with minimal support from the intermediate switches. First we derive the requirements for transmitting video over packet switched networks, surveying the reported work on human factors, and survey and compare the various algorithms for compressing video and determine their suitability for use over packet switched networks. We produce a taxonomy of congestion control schemes for packet switched networks. We present two novel approaches to congestion control which build on results from human factors experiments: a unicast scheme that we prove is analytically stable under some simple assumptions, and demonstrate working in simulations; and a multicast scheme that is designed to work over heterogeneous hosts and networks, and which has been proven in the wide-spread use of a particular workstation based video conferencing tool, known as IVS. We conclude with ruminations on the extent to which resource protection schemes need to be fielded in packet switches to support multimedia.