Video decoding method and device using cross-component prediction, and video encoding method and device using cross-component prediction

A video encoding method comprising:

• deriving weight information and deviation information about a chroma sample of an encoded adjacent chroma block neighboring a current chroma block and an encoded luma sample of an adjacent luma block corresponding to the adjacent chroma block in order to reconstruct chroma samples of the current chroma block;
• reconstructing luma samples of a current luma block corresponding to the current chroma block according to a prediction mode of the current luma block;
• determining the chroma samples of the current chroma block by using the predicted luma samples of the current luma block, the weight information, and the deviation information;
• and
• encoding residual values between the determined chroma samples of the current chroma block and an original chroma sample of the current chroma block.

A video decoding device comprising:

• a memory;
• and
• at least one processor connected to the memory,
• wherein the at least one processor is configured to:
• derive weight information and deviation information about a chroma sample of a reconstructed adjacent chroma block neighboring a current chroma block and a reconstructed luma sample of an adjacent luma block corresponding to the adjacent chroma block in order to reconstruct chroma samples of the current chroma block;
• reconstruct luma samples of a current luma block corresponding to the current chroma block according to a prediction mode of the current luma block;
• and
• reconstruct the chroma samples of the current chroma block by using the reconstructed luma samples of the current luma block, the weight information, and the deviation information.