deriving an intra prediction mode of a current chroma block;

selecting one or more luma reference sample lines for a current luma block from a plurality of luma reference sample lines neighboring the current luma block based on that the intra prediction mode of the current chroma block is an inter color component prediction mode, wherein the current luma block corresponds to the current chroma block;

deriving luma reference samples and chroma reference samples used for intra prediction of the current chroma block from the selected one or more luma reference sample line and a chroma reference sample line neighboring the current chroma block; and

generating a predicted block for the current chroma block based on the luma reference samples and the chroma reference samples according to the inter color component prediction mode,

wherein in deriving the intra prediction mode of the current chroma block,

whether to apply the inter color component prediction mode on the current chroma block is determined based on at least one of a size of the current chroma block, a shape of the current chroma block, and a coding parameter of the current chroma block, and

wherein based on that an upper boundary of the current luma block overlaps with a boundary of a coding tree unit (CTU), one upper luma reference sample line is selected.