Due to the shared nature of IP networks, the available network bandwidth is not constant and varies during transmission. In order to have better quality, efficient bandwidth utilization and network congestion management, the outgoing bitrate of a streaming application should adapt to changes in network traffic as fast as possible. The adaption time is very critical and plays an important role in the quality of the received video. More adaption time means that more packets are dropped in the network, which causes a lower video quality, and also causes congestion to persist for a longer period of time. In this paper, an adaptive bitrate shaping algorithm for the H.264/AVC encoder is presented. Network simulation results confirm that the proposed method works better than the existing shaping scheme of the JM12.2, which will be referred to as conventional method hereafter. The proposed method is able to adjust bitrate changes in less than 15 frames, compared to more than 20 frames that is required by the conventional method to reach the target bitrate. Moreover, the proposed method has no quality degradation or packet loss in the network simulations for all test sequences. The quality performance of the proposed method, in term of PSNR, is 4.635 dB higher than the conventional method in average for all test sequences. This enhancement in performance has been achieved with minimal computational complexity. It should be noted that the proposed method is applicable to any rate control method.
