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US 2022/0103810 A1Published application
Image decoding method and apparatus for deriving weight index information for weighted average when bi-prediction is applied
AssigneeLG Electronics Inc.
InventorsNaeri PARK, Junghak NAM, Hyeongmoon JANG
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Abstract
According to a disclosure of the present document, when the type of inter-prediction of a current block is indicated as biprediction, weight index information for a candidate within a merge candidate list or a sub-block merge candidate list may be derived, and coding efficiency may be increased.
Claims13
An image decoding method performed by a decoding apparatus, comprising:
- obtaining image information including inter-prediction mode information and residual information through a bitstream;
- generating residual samples based on the residual information;
- generating a merge candidate list of a current block based on the inter-prediction mode information;
- deriving motion information on the current block based on a candidate selected from the merge candidate list;
- generating L0 prediction samples and L1 prediction samples of the current block based on the motion information;
- generating prediction samples of the current block based on the L0 prediction samples, the L1 prediction samples, and weight information for the current block, wherein the weight information is derived based on a weight index for the selected candidate;
- and
- generating reconstructed samples based on the prediction samples and the residual sample,
- wherein the candidates include affine merge candidates, and each of the affine merge candidates includes at least two of a control point motion vector (CPMV) for a control point 0 (CP0), a CPMV for a control point 1 (CP1), a CPMV for a control point 2 (CP2), or a CPMV for a control point 3 (CP3), 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, the CP2 is related to a bottom-left corner of the current block and the CP4 is related to a bottom-right corner of the current block,
- based on a case that a first affine merge candidate is generated based on {CP0, CP1, CP2}, a weight index for the first affine merge candidate is set equal to a weight index for a specific block among neighboring blocks of the CP0, and
- based on a case that a second affine merge candidate is generated based on {CP1, CP2, CP3}, a weight index for the second affine merge candidate is set equal to a weight index for a specific block among neighboring blocks of the CP1.
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7-9. (canceled)
An image encoding method performed by an encoding apparatus, comprising:
- determining an inter-prediction mode of the current block and generating inter-prediction mode information indicating the inter-prediction mode;
- generating a merge candidate list of the current block based on the inter-prediction mode;
- generating selection information indicating one of candidates included in the merge candidate list;
- generating residual information based on residual samples of the current block;
- and
- encoding image information including the inter-prediction mode information, the selection information, and the residual information,
- wherein the candidates include affine merge candidates, and each of the affine merge candidates include at least two of a control point motion vector (CPMV) for control point 0 (CP0), a CPMV for a control point 1 (CP1), a CPMV for a control point 2 (CP2), or a CPMV for a control point 3 (CP3), 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, the CP2 is related to a bottom-left corner of the current block and the CP4 is related to a bottom-right corner of the current block,
- based on a case that a first affine merge candidate is generated based on {CP0, CP1, CP2}, a weight index for the first affine merge candidate is set equal to a weight index for a specific block among neighboring blocks of the CP0, and
- based on a case that a second affine merge candidate is generated based on {CP1, CP2, CP3}, a weight index for the second affine merge candidate is set equal to a weight index for a specific block among neighboring blocks of the CP1.
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(canceled)
A non-transitory computer readable digital storage medium storing a bitstream generated by an image encoding method, the method comprising:
- determining an inter-prediction mode of the current block and generating inter-prediction mode information indicating the inter-prediction mode;
- generating a merge candidate list of the current block based on the inter-prediction mode;
- generating selection information indicating one of candidates included in the merge candidate list;
- generating residual information based on residual samples of the current block;
- and
- encoding image information to generate the bitstream, wherein the image information includes the inter-prediction mode information, the selection information, and the residual information,
- wherein the candidates include affine merge candidates, and each of the affine merge candidates include at least two of a control point motion vector (CPMV) for control point 0 (CP0), a CPMV for a control point 1 (CP1), a CPMV for a control point 2 (CP2), or a CPMV for a control point 3 (CP3), 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, the CP2 is related to a bottom-left corner of the current block and the CP4 is related to a bottom-right corner of the current block,
- based on a case that a first affine merge candidate is generated based on {CP0, CP1, CP2}, a weight index for the first affine merge candidate is set equal to a weight index for a specific block among neighboring blocks of the CP0, and
- based on a case that a second affine merge candidate is generated based on {CP1, CP2, CP3}, a weight index for the second affine merge candidate is set equal to a weight index for a specific block among neighboring blocks of the CP1.
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Dependencies are inferred from the claim text.