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US 11,902,565 B2Granted
Inter-prediction-based image or video coding using sbTMVP
AssigneeLG Electronics Inc.
InventorsHyeongmoon Jang, Naeri Park, Junghak Nam
Life of this patent
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Abstract
According to the disclosure of the present document, in a subblock-based temporal motion vector prediction (sbTMVP), a position of a subblock for deriving a motion vector per subblock unit can be efficiently calculated, and thus video/image coding efficiency can be increased and hardware implementation can be simplified.
Claims3
An image decoding method performed by a decoding apparatus, the method comprising:
- deriving a position of a current subblock within a current block based on a center sample position of the current subblock;
- deriving a reference subblock on a collocated reference picture based on the position of the current subblock;
- deriving a subblock temporal motion vector predictor (sbTMVP) candidate based on a motion vector of the reference subblock;
- deriving a motion vector of the current subblock based on the sbTMVP candidate;
- generating prediction samples of the current block based on the motion vector of the current subblock;
- generating residual samples of the current block based on residual information obtained from a bitstream;
- and
- generating reconstruction samples based on the prediction samples and the residual samples,
- wherein the center sample position represents a position of a right-lower center sample positioned at a bottom right, among four samples positioned at the center,
- wherein for the reference subblock that is available, a motion vector of the available reference subblock is derived as the sbTMVP candidate,
- wherein the motion vector of the available reference subblock is derived based on a motion vector of a block covering a modified location derived based on a top-left sample position of the reference subblock, and
- wherein the modified location is derived by an equation ((xColSb>>3)<<3, (yColSb>>3)<<3), where the xColSb and the yColSb represent the x coordinate and y coordinate of the sample position of the reference subblock derived based on the center sample position of the current subblock, respectively, and >> represents an arithmetic right shift, and << represents an arithmetic left shift.
9 more elements
An image encoding method performed by an encoding apparatus, the method comprising:
- deriving a position of a current subblock within a current block based on a center sample position of the current subblock;
- deriving a reference subblock on a collocated reference picture based on the position of the current subblock;
- deriving a subblock temporal motion vector predictor (sbTMVP) candidate based on a motion vector of the reference subblock;
- deriving a motion vector of the current subblock based on the sbTMVP candidate;
- generating prediction samples of the current block based on the motion vector of the current subblock;
- generating residual samples derived based on the prediction samples;
- and
- encoding image information including information on the residual samples,
- wherein the center sample position represents a position of a right-lower center sample positioned at a bottom right, among four samples positioned at the center,
- wherein for the reference subblock that is available, a motion vector of the available reference subblock is derived as the sbTMVP candidate,
- wherein the motion vector of the available reference subblock is derived based on a motion vector of a block covering a modified location derived based on a top-left sample position of the reference subblock, and
- wherein the modified location is derived by an equation ((xColSb>>3)<<3, (yColSb>>3)<<3), where the xColSb and the yColSb represent the x coordinate and y coordinate of the sample position of the reference subblock derived based on the center sample position of the current subblock, respectively, and >> represents an arithmetic right shift, and << represents an arithmetic left shift.
9 more elements
A non-transitory computer-readable digital storage medium storing a bitstream generated by an image encoding method, the method comprising:
- deriving a position of a current subblock within a current block based on a center sample position of the current subblock;
- deriving a reference subblock on a collocated reference picture based on the position of the current subblock;
- deriving a subblock temporal motion vector predictor (sbTMVP) candidate based on a motion vector of the reference subblock;
- deriving a motion vector of the current subblock based on the sbTMVP candidate;
- generating prediction samples of the current block based on the motion vector of the current subblock;
- generating residual samples derived based on the prediction samples;
- and
- encoding image information including information on the residual samples to output the bitstream,
- wherein the center sample position represents a position of a right-lower center sample positioned at a bottom right, among four samples positioned at the center,
- wherein for the reference subblock that is available, a motion vector of the available reference subblock is derived as the sbTMVP candidate,
- wherein the motion vector of the available reference subblock is derived based on a motion vector of a block covering a modified location derived based on a top-left sample position of the reference subblock, and
- wherein the modified location is derived by an equation ((xColSb>>3)<<3, (yColSb>>3)<<3), where the xColSb and the yColSb represent the x coordinate and y coordinate of the sample position of the reference subblock derived based on the center sample position of the current subblock, respectively, and >> represents an arithmetic right shift, and << represents an arithmetic left shift.
9 more elements
Dependencies are inferred from the claim text.