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US 2022/0103809 A1Published application
Image decoding method and device for deriving weight index information for generation of prediction sample
AssigneeLG Electronics Inc.
InventorsNaeri PARK, Junghak NAM, Hyeongmoon JANG
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Abstract
According to the disclosure of the present document, when the inter prediction type of a current block indicates bi-prediction, weight index information for candidates in a merge candidate list or a sub-block merge candidate list can be derived, and thus coding efficiency can be increased.
Claims15
An image decoding method performed by a decoding apparatus, the method comprising:
- receiving image information comprising inter prediction mode information through a bitstream;
- generating a merge candidate list for a current block based on the inter prediction mode information;
- deriving motion information on the current block based on a candidate selected from among candidates in the merge candidate list;
- 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 a weight index for the current block, wherein the weight index is derived based on a weight index for the selected candidate,
- wherein the candidates comprise a constructed affine merge candidate, and the constructed affine merge candidate comprises control point motion vectors (CPMVs),
- wherein based on a case that the affine merge candidate comprises a CPMV0 for a control point 0 (CP0), a weight index for the constructed affine merge candidate is set equal to a weight index for the CP0, wherein the CP0 is related to a top-left corner of the current block, and
- wherein based on a case that the constructed affine merge candidate does not comprise the CPMV0 for the CP0, the weight index for the constructed affine merge candidate is set equal to a weight index for the CP1, wherein the CP1 is related to a top-right corner of the current block.
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10-12. (canceled)
An image encoding method performed by an encoding apparatus, the method comprising:
- determining an inter prediction mode of a current block and generating inter prediction mode information indicating the inter prediction mode;
- generating a merge candidate list for the current block based on the inter prediction mode;
- generating selection information indicating one candidate among candidates included in the merge candidate list;
- and
- encoding image information comprising the inter prediction mode information and the selection information,
- wherein the candidates comprise a constructed affine merge candidate, and the constructed affine merge candidate comprises control point motion vectors (CPMVs),
- wherein based on a case that the constructed affine merge candidate comprises CPMV0 for a control point 0 (CP0), a weight index for the constructed affine merge candidate is set equal to a weight index for the CP0, wherein the CP0 is related to a top-left corner of the current block, and
- wherein based on a case that the constructed affine merge candidate does not comprise the CPMV0 for the CP0, the weight index for the constructed affine merge candidate is set equal to a weight index for a control point 1 (CP1), wherein the CP1 is related to a top-right corner of the current block.
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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 a current block and generating inter prediction mode information indicating the inter prediction mode;
- generating a merge candidate list for the current block based on the inter prediction mode;
- generating selection information indicating one candidate among candidates included in the merge candidate list;
- and
- encoding image information to generate the bitstream, wherein the image information comprises the inter prediction mode information and the selection information,
- wherein the candidates comprise a constructed affine merge candidate, and the constructed affine merge candidate comprises control point motion vectors (CPMVs),
- wherein based on a case that the constructed affine merge candidate comprises CPMV0 for a control point 0 (CP0), a weight index for the constructed affine merge candidate is set equal to a weight index for the CP0, wherein the CP0 is related to a top-left corner of the current block, and
- wherein based on a case that the constructed affine merge candidate does not comprise the CPMV0 for the CP0, the weight index for the constructed affine merge candidate is set equal to a weight index for a control point 1 (CP1), wherein the CP1 is related to a top-right corner of the current block.
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Dependencies are inferred from the claim text.