A New Rate Control Scheme in Low Bit-Rate for H.264/AVC

摘要

Rate control is not a necessary part of the current video coding standards, as the network bandwidth and delay constraint, Rate control has become a key technique for video coding in order to obtain consecutive and high quality video picture, especially the low bit rate communication need the better efficiency rate control scheme. Rate control Scheme of basic unit in H.264 mainly adopts the linear MAD predict model and quadratic rate distortion model, in the process of implementing, after coding a macroblock, the parameters of model will be updated, and computes the quantization parameter of the current macroblock. So, its computation cost is very high, and its complexity is also very high, so, it is not fit the low bit rate communication, especially the real time communication. Through analyzing the rate control scheme of the H.264/AVC, the paper proposed an improved low complexity MAD weighted predict model, and make the accurate rate control in the macroblock layer to reduce the complexity of the rate control scheme to adapt the real time communication, and lastly carried out it in the JM98 platform of JVT. Extensive experiment results show the complexity of this scheme is lower than the JVT-G012rl of H.264, and the average PSNR of the standard test sequences increased 0.146dB, at the same time, its accuracy of the rate control averagely improved 0.506kpbs, it will fit the low bit rate communication if it is further modified.