In this work, we investigated the discrete linear quadratic (DLQ) rate control method for the transmission of MPEG2 streams in IP networks. We derived a transmission scheduling system by solving the DLQ control problem under disturbances. Our study shows that DLQ is superior to conventional proxy scheduling schemes especially in client buffer usage. For some videos that can only achieve 70%~80% of buffer usage using basic DLQ, we also propose improvements to attain higher buffer occupancy with no overflow. Transmission capacity and adjust method under heavy traffic are also discussed.