A prediction method for variable bit rate video traffic based on source information is presented. By analysing the source before encoding, any changes in the source traffic are detected and the bit rate of the current frame is predicted. In addition, a new channel rate for renegotiated constant bit rate service can be determined for future frames using the predicted bit rate and a bit rate updating algorithm. Simulation results show that the proposed method achieves a better prediction and requires a smaller buffer than the conventional approach.