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US 11,240,527 B2Granted
Image decoding method and device on basis of affine motion prediction using constructed affine MVP candidate in image coding system
AssigneeLG Electronics Inc.
InventorJaeho Lee
Life of this patent
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Abstract
An image decoding method performed by a decoding device according to the present disclosure comprises the steps of: obtaining motion prediction information relating to a current block from a bitstream; generating an affine MVP candidate list for the current block; deriving CPMVPs for CPs of the current block on the basis of the affine MVP candidate list; deriving CPMVDs for the CPs of the current block on the basis of the motion prediction information; deriving CPMVs for the CPs of the current block on the basis of the CPMVPs and the CPMVDs; and deriving prediction samples for the current block on the basis of the CPMVs.
Claims15
An image decoding method, by a decoding apparatus, comprising:
- obtaining motion prediction information for a current block from a bitstream;
- constructing an affine motion vector predictor (mvp) candidate list for the current block;
- deriving control point motion vector predictors (CPMVPs) for control points (CPs) of the current block based on the affine mvp candidate list;
- deriving control point motion vector differences (CPMVDs) for the CPs of the current block based on 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;
- and
- generating a reconstructed picture for the current block based on the derived prediction samples,
- wherein based on a constructed affine mvp candidate being available, the affine mvp candidate list includes the constructed affine mvp candidate,
- wherein the constructed affine mvp candidate includes candidate motion vectors for the CPs,
- wherein the CPs of the current block include CP0, CP1 and CP2,
- wherein based on absence of a neighboring block having the same reference picture as a reference picture of the current block in a first neighboring block group for the CP0, a candidate motion vector for the CP0 is not available,
- wherein based on absence of a neighboring block having the same reference picture as the reference picture of the current block in a second neighboring block group for the CP1, a candidate motion vector for the CP1 is not available,
- wherein based on absence of a neighboring block having the same reference picture as the reference picture of the current block in a third neighboring block group for the CP2, a candidate motion vector for the CP2 is not available,
- wherein based on the candidate motion vectors for the CP0, the CP1 and the CP2 being available, the constructed affine mvp candidate is available, and
- wherein based on at least one of the candidate motion vector for the CP0, the candidate motion vector for the CP1 or the candidate motion vector for the CP2 being not available, the constructed affine mvp candidate is not available and a process of deriving the constructed affine mvp candidate based on an available candidate motion vector among the candidate motion vectors is not performed.
13 more elements
An image encoding method, by an encoding apparatus, comprising:
- constructing an affine motion vector predictor (mvp) candidate list for a current block;
- deriving control point motion vector predictors (CPMVPs) for control points (CPs) of the current block based on the affine mvp candidate list;
- deriving CPMVs for the CPs of the current block;
- deriving control point motion vector differences (CPMVDs) for the CPs of the current block based on the CPMVPs and the CPMVs;
- and
- encoding motion prediction information including information on the CPMVDs,
- wherein based on a constructed affine mvp candidate being available, the affine mvp candidate list includes the constructed affine mvp candidate,
- wherein the constructed affine mvp candidate includes candidate motion vectors for the CPs,
- wherein the CPs of the current block include CP0, CP1 and CP2,
- wherein based on absence of a neighboring block having the same reference picture as a reference picture of the current block in a first neighboring block group for the CP0, a candidate motion vector for the CP0 is not available,
- wherein based on absence of a neighboring block having the same reference picture as the reference picture of the current block in a second neighboring block group for the CP1, a candidate motion vector for the CP1 is not available,
- wherein based on absence of a neighboring block having the same reference picture as the reference picture of the current block in a third neighboring block group for the CP2, a candidate motion vector for the CP2 is not available,
- wherein based on the candidate motion vectors for the CP0, the CP1 and the CP2 being available, the constructed affine mvp candidate is available, and
- wherein based on at least one of the candidate motion vector for the CP0, the candidate motion vector for the CP1 or the candidate motion vector for the CP2 being not available, the constructed affine mvp candidate is not available and a process of deriving the constructed affine mvp candidate based on an available candidate motion vector among the candidate motion vectors is not performed.
11 more elements
A non-transitory computer-readable storage medium storing a bitstream generated by a method, the method comprising:
- constructing an affine motion vector predictor (mvp) candidate list for a current block;
- deriving control point motion vector predictors (CPMVPs) for control points (CPs) of the current block based on the affine mvp candidate list;
- deriving CPMVs for the CPs of the current block;
- deriving control point motion vector differences (CPMVDs) for the CPs of the current block based on the CPMVPs and the CPMVs;
- encoding motion prediction information including information on the CPMVDs;
- and
- generating the bitstream including the motion prediction information,
- wherein based on a constructed affine mvp candidate being available, the affine mvp candidate list includes the constructed affine mvp candidate,
- wherein the constructed affine mvp candidate includes candidate motion vectors for the CPs,
- wherein the CPs of the current block include CP0, CP1 and CP2,
- wherein based on absence of a neighboring block having the same reference picture as a reference picture of the current block in a first neighboring block group for the CP0, a candidate motion vector for the CP0 is not available,
- wherein based on absence of a neighboring block having the same reference picture as the reference picture of the current block in a second neighboring block group for the CP1, a candidate motion vector for the CP1 is not available,
- wherein based on absence of a neighboring block having the same reference picture as the reference picture of the current block in a third neighboring block group for the CP2, a candidate motion vector for the CP2 is not available,
- wherein based on the candidate motion vectors for the CP0, the CP1 and the CP2 being available, the constructed affine mvp candidate is available, and
- wherein based on at least one of the candidate motion vector for the CP0, the candidate motion vector for the CP1 or the candidate motion vector for the CP2 being not available, the constructed affine mvp candidate is not available and a process of deriving the constructed affine mvp candidate based on an available candidate motion vector among the candidate motion vectors is not performed.
12 more elements
Dependencies are inferred from the claim text.