Patent ID: 11889106
Assignee: LG ELECTRONICS INC.
Field: Audio-visual technology (Electrical engineering)
Classification: CPC H | IPC H

Claim 0:
1. A decoding apparatus for image decoding, the decoding apparatus comprising:
a memory; and
at least one processor connected to the memory, the at least one processor configured to:
obtain motion prediction information for a current block from a bitstream;
configure an affine motion vector predictor (MVP) candidate list for the current block;
derive control point motion vector predictors (CPMVPs) for control points (CPs) of the current block based on the affine MVP candidate list;
derive control point motion vector differences (CPMVDs) for CPs of the current block based on the motion prediction information;
derive control point motion vectors (CPMVs) for CPs of the current block based on the CPMVPs and the CPMVDs;
derive prediction samples for the current block based on the CPMVs; and
generate a reconstructed picture for the current block based on the derived prediction samples,
wherein the at least one processor further configured to:
check whether a first affine MVP candidate is available, wherein the first affine MVP candidate is available based on a first block in a left block group being coded with an affine motion model and a reference picture of the first block being same as a reference picture of the current block;
check whether a second affine MVP candidate is available, wherein the second affine MVP candidate is available based on a second block in a top block group being coded with the affine motion model and a reference picture of the second block being same as the reference picture of the current block,
wherein the left block group includes a bottom-left corner neighboring block of the current block, and a first left neighboring block adjacent to an upper side of the bottom-left corner neighboring block, and
wherein the top block group includes a top-right corner neighboring block of the current block, a first top neighboring block adjacent to a left side of the top-right corner neighboring block, and a top-left corner neighboring block; and
check whether a third affine MVP candidate available based on a number of the available affine MVP candidate being less than 2,
wherein a 6-parameter affine model is used to an inter prediction,
wherein for the 6-parameter affine model being used to the inter prediction, the third MVP affine candidate is available based on a first motion vector for CP0, a second motion vector for CP1 and a third motion vector for CP2 of the current block being derived from a top-left block group of the current block, a top-right block group of the current block and the left block group respectively, and
wherein the top-left block group includes the top-left corner neighboring block of the current block, a second left neighboring block adjacent to a bottom side of the top-left corner neighboring block, and a second top neighboring block adjacent to a right side of the top-left corner neighboring block, and the top-right block group includes the top-right corner neighboring block and the first top neighboring block.