Patent ID: 11956451
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. An image decoding apparatus for an image decoding, the image decoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
obtain image information comprising prediction mode information for a current chroma block;
derive one of a plurality of cross-component linear model (CCLM) prediction modes as a CCLM prediction mode of the current chroma block, based on the prediction mode information;
derive a sample number of neighboring chroma samples of the current chroma block based on a width or height of the current chroma block and a specific value;
derive the neighboring chroma samples of the sample number;
derive down sampled neighboring luma samples related with the neighboring chroma samples and down sampled luma samples of a current luma block;
calculate CCLM parameters based on the neighboring chroma samples and the down sampled neighboring luma samples;
derive prediction samples for the current chroma block based on the CCLM parameters and the down sampled luma samples; and
generate reconstructed samples for the current chroma block based on the prediction samples,
wherein the specific value is derived as 2,
wherein the width or height of the current chroma block is N,
wherein the plurality of CCLM prediction modes include a left top LM mode, a top LM mode and a left LM mode,
wherein based on the N being less than or equal to the specific value, the sample number of the neighboring chroma samples is derived as 2N, and
wherein based on the N being greater than the specific value, the sample number of the neighboring chroma samples is derived as 4.