Fast SHVC inter-coding based on Bayesian decision with coding depth estimation

The scalable extension of the high efficiency video coding standard named SHVC supports flexible access for various terminals in heterogeneous networks. However, it is difficult to use in real-time scenarios because of the high complexity of the hierarchical coding structure. In this paper, a novel method for SHVC inter-coding is proposed to reduce the coding complexity in a manner that is compatible with quality scalability and spatial scalability. First, the depth range of the coding tree units is estimated from a reference table generated from a statistical probability distribution based on the correlation between the current coding unit (CU) and its adjacent CUs. Within this depth range, a fast CU partitioning method based on Bayesian minimum risk and a fast prediction unit (PU) selection method based on Bayesian maximum probability are adopted to improve time efficiency. Three different methods, namely, histogram estimation, Gaussian modelling and neighbouring prediction, are used to calculate the conditional probabilities for discrete or continuous features in the Bayesian decision method. The significant advantage of the proposed method is that the time savings in the enhancement layer for each sequence exceeds 60% with negligible quality loss.