Cross-component inter chroma prediction in video coding

This paper presents an Inter Cross-Component Prediction (CCP) merge mode, aiming primarily to enhance the coding performance in inter chroma prediction. Initially, a CCP model candidate list is constructed, which consists of both derived CCP model candidates and inherited CCP model candidates. Subsequently, the candidates in this list are reordered, and the one with the lowest template cost is implicitly chosen to generate the CCP model-estimated prediction, eliminating the need to transmit any index. Finally, a weighted combination of the CCP model-estimated prediction and the motion-compensated prediction is employed to generate the final chroma prediction. Moreover, the proposed method is further extended to the zero CBF case. Experimental results demonstrate that, under the JVET common test conditions for exploring next generation video coding technologies beyond VVC, compared with the existing ECM in RA/LDB configurations, the proposed Inter CCP merge mode leads to an average Bjontegaard Delta rate (BD-rate) change of 0.01%/-0.69%/-0.76% and -0.03%/-2.31%/-2.38% on the Y/Cb/Cr components, respectively. Currently, the Inter CCP merge mode has been incorporated into ECM.