Patent ID: 11871035
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 1:
2. An encoding apparatus for image encoding, the encoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
derive prediction samples for a current block;
derive residual samples for the current block based on the prediction samples;
derive transform coefficients for the current block based on a primary transform for the residual samples;
derive modified transform coefficients from the transform coefficients by applying a low-frequency non-separable transform (LFNST); and
encode residual information on the modified transform coefficients, and an LFNST index related to an LFNST matrix that is applied to the LFNST,
wherein the LFNST index is encoded based on whether or not a width and a height of the current block satisfy a condition that the LFNST is applied,
wherein whether or not the condition that the LFNST is applied is satisfied is determined based on a tree-type of the current block, a color format of the current block, and whether or not an intra sub partitions (ISP) is applied to the current block, and
wherein in case the ISP is applied, based on the width and the height of the current block corresponding to a subpartition block being equal to 4 or more, the LFNST index is encoded.