US 12,395,678 B2
CCLM prediction-based image decoding method and apparatus in image coding system
Jangwon Choi, Seoul (KR); Jin Heo, Seoul (KR); Seunghwan Kim, Seoul (KR); Sunmi Yoo, Seoul (KR); Jungah Choi, Seoul (KR); and Ling Li, Seoul (KR)
Assigned to LG ELECTRONICS INC., Seoul (KR)
Filed by LG ELECTRONICS INC., Seoul (KR)
Filed on Mar. 5, 2024, as Appl. No. 18/595,710.
Application 18/595,710 is a continuation of application No. 17/432,372, granted, now 11,973,977, previously published as PCT/KR2020/002532, filed on Feb. 21, 2020.
Claims priority of provisional application 62/817,570, filed on Mar. 13, 2019.
Claims priority of provisional application 62/808,844, filed on Feb. 22, 2019.
Prior Publication US 2024/0305814 A1, Sep. 12, 2024
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/593 (2014.01); H04N 19/11 (2014.01); H04N 19/132 (2014.01); H04N 19/176 (2014.01); H04N 19/186 (2014.01); H04N 19/196 (2014.01)
CPC H04N 19/593 (2014.11) [H04N 19/11 (2014.11); H04N 19/132 (2014.11); H04N 19/176 (2014.11); H04N 19/186 (2014.11); H04N 19/196 (2014.11)] 3 Claims
OG exemplary drawing
 
1. An image decoding method performed by a decoding apparatus, the method comprising:
deriving an intra prediction mode for a current chroma block as a left-top based cross-component linear model (CCLM) mode based on prediction mode information on the current chroma block;
deriving downsampled luma samples based on a current luma block;
deriving downsampled neighboring luma samples based on neighboring luma samples of the current luma block;
deriving a CCLM parameter based on the downsampled neighboring luma samples and neighboring chroma samples of the current chroma block; and
generating prediction samples of the current chroma block based on the CCLM parameter and the downsampled luma samples,
wherein a width and a height of the current chroma block are N,
wherein based on N being greater than a threshold value, downsampled left neighboring luma samples, left neighboring chroma samples, downsampled top neighboring luma samples and top neighboring chroma samples are derived, and the number of the downsampled left neighboring luma samples, the number of the left neighboring chroma samples, the number of the downsampled top neighboring luma samples and the number of the top neighboring chroma samples are equal to the threshold value.