An adaptive residual decorrelation method for HEVC

In this paper, we propose an explicit residual decorrelation method to improve the coding performance for 4:4:4 chroma format conforming HEVC framework. The energy from a residual signal is gathered to the primary component by decorrelation of color space. The transform matrix as decorrelation is derived from reference pixel value by using singular value decomposition for each prediction unit. Since the derivation is applied in both encoder and decoder side, the identical matrix is obtained for both sides. Compared to the previous works, the proposed method applies only for the meaningful unit while an enabled flag is explicitly signaled as side information. The proposed method is implemented on HEVC test model. For the RGB/YUV 4:4:4 chroma format sequences, the coding gains in BD-rate are up to 23.3%/4.9%, respectively. Compared to the result by the previous works, average gains are slightly decreased, while each gain of sequence is always better than that by conventional method.