| CPC H04N 19/139 (2014.11) [H04N 19/105 (2014.11); H04N 19/159 (2014.11); H04N 19/176 (2014.11); H04N 19/52 (2014.11); H04N 19/577 (2014.11); H04N 19/593 (2014.11)] | 13 Claims |

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1. An image decoding method performed by an image decoding apparatus, the image decoding method comprising:
deriving a motion shift of a current block using motion vector of a neighboring block of the current block;
determining a collocated block of the current block using the motion shift;
deriving a motion vector for at least one control point (CP) of the determined collocated block; and
deriving at least one control point motion vector (CPMV) of the current block using the motion vector for the at least one CP,
wherein the deriving the motion vector for the at least one CP of the determined collocated block comprises:
determining availability of a first CP, a second CP and a third CP of the determined collocated block; and
deriving a motion vector for at least one of the first CP, the second CP or the third CP based on the determination of availability,
wherein availability of the at least one CP is determined based on whether an intra prediction mode or an intra block copy (IBC) mode applies to a block including coordinates of the at least one CP.
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