High-quality symmetric Wyner–Ziv coding scheme for low-motion videos

Abstract. Traditional Wyner–Ziv video coding (WZVC) structures require either intra (Key) or Wyner–Ziv (WZ) coding of frames. Unfortunately, keeping the video quality approximately constant implies drastic bit-rate fluctuations because consecutive frames of different types (Key or WZ) present significantly different compression performances. Moreover, certain scenarios severely limit rate fluctuation. This work proposes a WZVC scheme with low bit-rate fluctuations based on a symmetric coding structure. First, this work investigates the performance of a generic nonasymmetric distributed source coding structure, showing that the low-density parity-check accumulate channel decoding method is best suited. This is used as a basis to design a symmetric WZVC scheme in which every input video frame is divided into four parallel subframes through subsampling, and then the subframes are encoded by using a symmetric method. Compared with the traditional asymmetric WZVC scheme, the proposed scheme can achieve higher bit-rate stability over time, which is a great advantage to guarantee a reliable transmission in many wireless communication application environments in which bit-rate fluctuations are strongly constrained. Simulation results show the effectiveness of the proposed symmetric WZVC scheme in maintaining a steady bit rate and quality, as well as a quality comparison with the traditional WZVC scheme.