CCLM prediction-based video decoding method and apparatus in video coding system

摘要

The image decoding method performed by the decoding apparatus according to this document includes deriving one of a plurality of CCLM prediction modes as a cross-component linear model (CCLM) prediction mode of a current chroma block based on prediction mode information, the current deriving the sample number of neighboring chroma samples of the current chroma block based on the CCLM prediction mode of the chroma block, the size of the current chroma block, and a specific value; deriving the number of neighboring chroma samples of the sample number; calculating CCLM parameters based on neighboring chroma samples and down-sampled neighboring luma samples; deriving prediction samples for the current chroma block based on the CCLM parameters and the down-sampled luma samples; , the specific value is characterized in that it is derived as 2.