	US 12,081,739 B2
	Image coding method based on affine motion prediction, and device for same
Jaeho Lee, Seoul (KR)
Assigned to GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD., Guangdong (CN)
Filed by GUANGDONG OPPO MOBILE TELECOMMUNICATIONS CORP., LTD., Guangdong (CN)
Filed on Feb. 17, 2023, as Appl. No. 18/111,512.
Application 18/111,512 is a continuation of application No. 17/710,086, filed on Mar. 31, 2022, granted, now 11,611,744.
Application 17/710,086 is a continuation of application No. 17/060,657, filed on Oct. 1, 2020, granted, now 11,323,696, issued on May 3, 2022.
Application 17/060,657 is a continuation of application No. PCT/KR2019/003816, filed on Apr. 1, 2019.
Claims priority of provisional application 62/651,244, filed on Apr. 1, 2018.
Prior Publication US 2023/0209044 A1, Jun. 29, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. H04N 19/105 (2014.01); H04N 19/132 (2014.01); H04N 19/137 (2014.01); H04N 19/176 (2014.01)

CPC H04N 19/105 (2014.11) [H04N 19/132 (2014.11); H04N 19/137 (2014.11); H04N 19/176 (2014.11)]

4 Claims

1. A picture decoding method performed by a decoding apparatus, the method comprising:

obtaining motion prediction information and residual information from a bitstream;

generating an affine motion vector predictor (MVP) candidate list including affine MVP candidates for a current block;

selecting one of the affine MVP candidates in the affine MVP candidate list based on an affine MVP candidate index in the motion prediction information;

deriving control point motion vector predictors (CPMVPs) for control points (CPs) of the current block based on the selected affine MVP candidate;

deriving control point motion vector differences (CPMVDs) for the CPs of the current block based on information on the CPMVDs for the CPs included in the motion prediction information;

deriving control point motion vectors (CPMVs) for the CPs of the current block based on the CPMVPs and the CPMVDs;

deriving prediction samples for the current block based on the CPMVs for the CPs of the current block;

deriving residual samples for the current block based on the residual information; and

generating reconstructed samples for the current block based on the prediction samples and the residual samples,

wherein the affine MVP candidates in the affine MVP candidate list comprise a first affine MVP candidate and a second affine MVP candidate,

wherein the CPs include a CP0, a CP1 and a CP2, and the CPMVPs for the CPs include a first MVP for the CP0, a second MVP for the CP1 and a third MVP for the CP2,

wherein the CP0 is located in a top-left corner of the current block, the CP1 is located in a top-right corner of the current block and the CP2 is located in a bottom-left corner of the current block,

wherein the first MVP, the second MVP and the third MVP constituting the first affine MVP candidate are derived based on a first block being coded based on an affine motion model in a left block group,

wherein the left block group includes a bottom-left corner neighboring block of the current block and a left neighboring block adjacent to a top of the bottom-left corner neighboring block,

wherein the first MVP, the second MVP and the third MVP constituting the second affine MVP candidate are derived based on a second block being coded based on the affine motion model in a top block group,

wherein the top block group includes a top-right corner neighboring block, a top neighboring block adjacent to a left of the top-right corner neighboring block and a top-left corner neighboring block of the current block,

wherein the left block group excludes the top-right corner neighboring block, the top neighboring block and the top-left corner neighboring block, and

wherein the top block group excludes the bottom-left corner neighboring block and the left neighboring block.