Recommendations for Switching Frames in Mobile Video Streaming

Real time multimedia application is a challenging issue in the mobile networks, due to high compression requirements and limited and varying channel bandwidth. H.264/AVC addresses these issues with its excellent coding efficiency, error resiliency features and provision of bit rate adaptivity, using switching (SP-) frames. To reduce the quantization errors due to multiple quantization, SP- frames are usually coded with finer quantization parameters (QP) than the rest of the sequence, resulting in an increased bit rate, sometimes exceeding to that of intra (I-) frames. This limits the basic advantages of SP-frames over I-frames and that is better coding efficiency, leading to poor utilization of the resources like bandwidth. Thus the question is what is the safe range of QP such that the bit rate of the switching frames does not exceed that of the I-frames? The aim of this paper to suggest a solution to this problem by analyzing characteristics of SP-frames and to suggest a safe range of QP for switching frames ensuring that its bit rate remains lower than that of I-frames.