Novel H.26X optimal rate control for low-delay communications

The existing rate control schemes in the literature calculates the quantization parameters of macro-blocks (MB) based on the quadratic/log rate models. Actually, this model may not be good because this model does not estimate well at some particular bit rates. This work investigates the relationships of bit rate and distortion with the MB quantization step size and standard deviation of MB prediction errors. We find that the linear rate and linear distortion models are established. Then we present the proposed rate control schemes based on these models. The proposed algorithm introduces a low quantization overhead, low computation complexity to calculate the optimal quantization step size, independence of the distortion factors and low memory usage compared with TMN8 rate control. The experimental results suggests that our scheme can achieve PSNR gain over TMN8.