Video decoding apparatus, video coding apparatus, video decoding method, video coding method, and storage medium

A method performed by a video coding apparatus, the method comprising:

• scaling a vector predictor candidate (mvcx, mvcy) of a target block to be encoded to obtain a scaled vector predictor candidate (mvcx′, mvcy′) based on picture information of pictures and motion vector information including motion vectors (mvCol) of blocks that are spatially or temporally adjacent to the target block and reference picture identifiers indicating pictures that the motion vectors (mvCol) refer to;
• and
• correcting the scaled vector predictor candidate toward 0 by a predetermined amount “a”,
• wherein when a predetermined precision N after a decimal point of a scaling factor (Scale) is 8 bits, the scaling and the correcting are represented by formulas:
• mvcx′=sign(Scale×mvcx)×{(abs(Scale×mvcx)−a+128)>>8}
• mvcy′=sign(Scale×mvcy)×{(abs(Scale×mvcy)−a+128)>>8}
• abs( ):
• a function that returns an absolute value
• sign( ):
• a function that returns a sign(1 or −1);
• and
• wherein the predetermined amount “a” is greater than or equal to 1 and less than or equal to 2N−2.