Optimal quantization for dc coefficient of Wyner-Ziv frame in unidirectional distributed video coding

This paper presents a rate-distortion based optimal quantization scheme for DC coefficient in the unidirectional Wyner-Ziv (WZ) video coding system. In the proposed scheme, a new rate-distortion (RD) model is developed to find out an optimal quantization step (OQS) for DC coefficient. More specifically, the effects of quantization step on both distortion and rate are considered in our presented RD model. And OQS, optimal in term of RD cost, can be solved for DC coefficient, at the expense of increasing the coding complexity slightly. The comparison of RD performance between the Wyner-Ziv video coding system using our proposed scheme and the baseline system without using OQS is presented. The results show that quantization with OQS for DC coefficient can improve the average PSNR of WZ frames by 0.3~1.0 dB.