A Study on the Quantization Scheme in H.264/AVC and Its Application to Rate Control

Compared with previous video coding standards, H.264/AVC employs a division-free quantization scheme. The relation between quantization parameter and quantization step changes from general linear to exponential as well. In this paper, we first analyze the relation between rate and quantization step-size and derive a new rate-distortion (R-D) model. An efficient rate control scheme is then developed based on the new R-D model. The proposed rate control scheme is implemented into the H.264/AVC reference software, with which the better coding performance can be achieved. Experimental results show that the PSNR of the proposed rate control scheme is averagely 0.23dB over the current rate control scheme in H.264/AVC test model and 0.41dB over the coding scheme with fixed quantization parameter, and meanwhile, the complexity of the proposed rate control scheme is much lower than the original one.