Patent ID: 11930185
Assignee: BEIJING BYTEDANCE NETWORK TECHNOLOGY CO., LTD.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 15:
16. A non-transitory computer-readable recording medium storing a bitstream of a video which is generated by a method performed by a video processing apparatus, wherein the method comprises:
determining, for a conversion between a current video block of the video and the bitstream of the video, parameters of a cross-component linear model (CCLM) based on maximum and minimum values of chroma and luma samples of one or more groups of chroma and luma samples selected from neighboring luma and chroma samples of the current video block; and
generating the bitstream based on the parameters of the CCLM; and
wherein the chroma and luma samples for each group are selected based on a width and a height of the current video block,
wherein the one or more groups of chroma and luma samples comprise S0, S1, . . . , Sm, each of S0, S1, . . . , Sm indicating a corresponding group of chroma and luma samples and N indicating a number of the one or more groups, and wherein 1≤m≤N−1, wherein m and N are non-negative integers, wherein a maximum luma value is calculated as maxL=f1(maxLS0, maxLS1, . . . , maxLSm), wherein f1 is a first function and maxLSi is a maximum luma value of a group Si of the one or more groups, wherein a maximum chroma value is calculated as maxC=f2(maxCS0, maxCS1, . . . , maxCSm), wherein f2 is a second function and maxCSi is a chroma value of the group Si corresponding to maxLSi, wherein a minimum luma value is calculated as minL=f3(minLS0, minLS1, . . . , minLSm), wherein f3 is a third function and minLSi is a minimum luma value of the group Si, wherein a minimum chroma value is calculated as minC=f4(minCS0, minCS1, . . . , minCSm), wherein f4 is a fourth function and minCSi is a chroma value of the group Si, corresponding to minLSi and wherein the parameters of the linear model comprise α and β that are calculated as

α=(maxC−minC)/(maxL−minL) and β=minC−α×minL, and

wherein in a case that samples are from an above row of the current video block, S0 comprises a first portion of the samples, wherein each sample of the first portion has a x-coordinate that satisfies (x-coordinate) % P=Q, and S1 comprises a second portion of the samples, wherein each sample of the second portion has the x-coordinate that satisfies (x-coordinate) % P≠Q, and
wherein % is a modulo operator and P and Q are non-negative integers, wherein i) P=2 and Q=1, or ii) P=2 and Q=0, or iii) P=4 and Q=0.