Adaptive MPEG-4 Source Rate Control over Internet for ADSL Subscribers

Abstract

This paper proposes a mechanism that integrates a MPEG-4 adaptive source rate control algorithm and a bi-directional negotiation scheme over Internet for ADSL (Asymmetric Digital Subscriber Line) subscribers to maintain the quality of real time MPEG-4 applications. We introduce an IP/MPLS/POS (IP / MultiProtocol Label Switching / Packet Over SONET/SDH) network architecture to improve the packetization efficiency for MPEG-4 encoded bit-streams. This architecture can also reduce the delay and loss of feedback control packets. We show that the VOP (Video Object Plane) based packetization scheme has the best performance under the proposed network architecture. According to the network status, the proposed MPEG-4 adaptive source rate control algorithm adjusts the target quantization value instead of reducing the target encoding rate directly. Simulation results show that, with the three MPEG-4 video sequences and four types of Internet traffic conditions, the proposed mechanism always has the best performance. In summary, the higher the video complexity of MPEG-4 sequence, the more PSNR improvement the proposed mechanism; moreover, the higher the traffic load, the more PSNR improvement the proposed mechanism.