Cross-Component Compensation for Intra Chroma Block with Block Vector

Although VVC standardization is complete, there is a continued exploration of new video coding tools under the name of beyond VVC capability. In this effort, various new techniques such as cross-component or non-cross-component schemes have been developed so far, and among them, the direct block vector (DBV) mode, which is one of the non-cross-component prediction schemes, conducts block copy of the reference block by means of block vector information estimated using co-located luma area. However, in a dual tree structure, there can be multiple luma blocks in the co-located luma area corresponding to a chroma block, and one block vector which is estimated from the co-located luma area may not be optimal for the DBV mode. To overcome this, in this paper, a cross-component-based compensation method is proposed to use a convolution function for a chroma block prediction. Experiment under the AI configuration using the first 50 frames of sequences from JVET common test conditions shows 0.02% BDBR loss in Y channel but BDBR gains of 0.17% and 0.07% respectively in Cb and Cr channel with negligible encoding complexity increase against ECM-9.0.