The emergence of multimedia applications has spurred interest in transport protocols with flexible transmission control. In TCP-Friendly Rate Control (TFRC), the multimedia transmission rate is adapted using the TCP throughput equation. This model, defined in terms of the relationship between throughput, round-trip time and loss rate, ensures that the resulting protocol is TCP compatible. However, standard TFRC wastes bandwidth because it is slow to detect changes in the available capacity. In this paper, the authors take a new direction in tackling this problem. The classical TCP filter used in the estimation of the round-trip time is replaced by two filters namely the adaptive TCP filter and adaptive Kalman filter.