Patent ID: 11943445
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 2:
3. An image encoding method performed by an encoding apparatus, the method comprising:
deriving prediction samples for a current block;
deriving residual samples for the current block based on the prediction samples;
deriving transform coefficients by performing a primary transform on the residual samples;
deriving a flag variable array related to whether an LFNST is applied to the current block;
performing the LFNST based on the flag variable array and the transform coefficients;
performing quantization on the transform coefficients; and
encoding and outputting image information comprising an LFNST index generated based on the flag variable array and the quantized transform coefficients,
wherein the flag variable array is defined as a one-dimensional array,
wherein flag variables included in the flag variable array are derived for each color component of the current block, and
wherein the flag variable array is derived for each color component of the current block,
wherein the flag variable array includes a first flag variable for a luma component, a second flag variable for a Cb component and a third flag variable for a Cr component,
wherein the first flag variable is set to 1 and the second flag variable and the third flag variable are set to 0, based on a tree type of the current block being a single tree and a value of the LFNST index being greater than 0,
wherein the first flag variable is set to 1 based on a tree type of the current block being a dual tree luma and the value of the LFNST index being greater than 0,
wherein the second flag variable and the third flag variable are set to 1 based on a tree type of the current block being a dual tree chroma and a value of the LFNST index being greater than 0,
wherein the quantization is performed based on a scaling list, and
wherein whether to apply the scaling list for the each color component of the current block is determined based on a value of a flag variable allocated for the each color component in the flag variable array.