Patent ID: 11863746
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A method for decoding an image signal, comprising:
performing secondary inverse-transform on secondary-transformed coefficients of a current block to generate primary-transformed coefficients for the current block;
performing primary inverse-transform on the primary-transformed coefficients of the current block to generate residual samples of the current block;
performing intra prediction on the current block to generate prediction samples of the current block; and
generate reconstructed samples of the current block based on the prediction samples and the residual samples of the current block,
wherein the performing the secondary inverse-transform comprises:
determining a non-separable transform matrix based on an intra prediction mode of the current block; and
applying the non-separable transform matrix to the secondary-transformed coefficients of the current block, and
wherein an input length and an output length of the secondary inverse-transform are respectively determined as 8 and 16, based on a size of the current block being 4×4.