Patent ID: 11882289
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 10:
11. A non-transitory computer-readable digital storage medium that stores a bitstream generated by an image encoding method, the image encoding method comprising:
deriving prediction samples for a current block;
deriving residual samples for the current block based on the prediction samples;
deriving transform coefficients for the current block based on a primary transform for the residual samples;
deriving modified transform coefficients for the current block based on transform coefficients of a first region at a top-left of the current block and a predetermined Low Frequency Non-Separable Transform (LFNST) matrix; and
encoding residual information related to the modified transform coefficients and an LFNST index indicating the LFNST matrix to generate the bitstream,
wherein based on a size of the current block being 4×4, the first region to which the LFNST matrix is applied is a top-left 4×4 area of the current block,
wherein based on the size of the current block being 8×8, the first region to which the LFNST matrix is applied is top-left, top-right, and bottom-left 4×4 areas of the current block, and
wherein based on one of a width or height of the current block being greater than 4 and the other of the width or height of the current block being 4, the first region to which the LFNST matrix is applied is a top-left 4×4 area of the current block.