| CPC H04N 19/105 (2014.11) [H04N 19/132 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11)] | 3 Claims |

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1. An image decoding method performed by a decoding apparatus, the image decoding method comprising:
receiving image information including inter prediction mode information through a bitstream;
deriving an inherited affine candidate and a constructed affine candidate based on a neighboring block of a current block, based on the inter prediction mode information;
generating a merge candidate list of the current block based on the inherited affine candidate and the constructed affine candidate;
selecting one candidate from among candidates included in the merge candidate list;
deriving motion information on the current block based on the selected candidate;
generating L0 prediction samples and L1 prediction samples of the current block based on the motion information; and
generating prediction samples of the current block based on the L0 prediction samples, the L1 prediction samples, and weight information, wherein the weight information is weight information for a bi-prediction and is derived based on a weight index for the selected candidate,
wherein the constructed affine candidate includes control point motion vectors (CPMVs), and
wherein based on a case that the constructed affine candidate is generated based on {CP0, CP1, CP3}, a weight index for the constructed affine candidate is derived based on a weight index for the CP0, wherein the CP0 is related to a top-left corner of the current block, the CP1 is related to a top-right corner of the current block and the CP3 is related to a bottom-right corner of the current block.
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