Model Correction for Cross-Channel Chroma Prediction

A new inter-channel coding mode named LM mode has been intensively explored in the HEVC standardization project. This mode predicts the chroma signal from the luma signal using a linear model whose parameters are inferred from neighboring reconstructed luma and chroma samples. Although this mode presents very good coding efficiency, it is observed that ill cases in the linear parameters calculation can be detected and fixed. This paper gives an overview of the LM mode and presents a novel model correction scheme to detect and correct those ill cases. Simulation results show significant bit-rate savings by the proposed correction scheme with limited added complexity.