Patent ID: 11968397
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 based on an intra prediction mode applied to a target block of a picture;
deriving an array of residual samples based on the prediction samples;
deriving a two-dimensional array based on a primary transform of the array of residual samples;
deriving a plurality of second transform coefficients from the two-dimensional array, wherein the plurality of second transform coefficients are derived from a top-left 8×8 region of the two-dimensional array, excluding a bottom-right 4×4 region within the top-left 8×8 region;
deriving a plurality of first transform coefficients based on a secondary transform of the plurality of second transform coefficients, wherein the plurality of first transform coefficients are mapped to a top-left 4×4 region of the target block; and
encoding residual information related to the plurality of first transform coefficients.