Image encoding/decoding method and device for a spatial merge candidate derived from a spatially adjacent block of the target block

An image encoding method performed by an image encoding apparatus, the method comprising:

• constructing a merge candidate list of a target block;
• determining whether a motion vector predictor of the target block from the merge candidate list can be adjusted by a motion vector offset;
• in response to that the motion vector predictor is determined to be adjusted, selecting the motion vector predictor of the target block from one of two merge candidates included in the merge candidate list, wherein the only two merge candidates in the merge candidate list can be selected as the motion vector predictor and adjusted by the motion vector offset and any remaining merge candidate in the merge candidate list that is not one of the two merge candidates cannot be selected;
• determining a motion vector precision of the motion vector offset for the target block;
• determining the motion vector offset based on the motion vector precision;
• determining a motion vector of the target block by adjusting the motion vector predictor of the target block by the motion vector offset;
• encoding merge candidate information indicating the motion vector predictor from the two merge candidates included in the merge candidate list;
• and
• encoding motion vector offset information comprising first information on a sign of the motion vector offset and second information on an absolute value of the motion vector offset, wherein the second information is encoded using the motion vector precision,
• wherein the merge candidate list includes a spatial merge candidate derived from a spatially adjacent block of the target block, the spatially adjacent block being adjacent to top-right, top, top-left, left, or bottom-left of the target block.

A data transmitting method to transmit a bitstream that is generated by encoding the image data based on an image encoding method,

• wherein the bitstream comprising:
• merge candidate information indicating a motion vector predictor from two merge candidates included in a merge candidate list;
• and
• motion vector offset information comprising first information on a sign of a motion vector offset and second information on an absolute value of the motion vector offset, wherein the second information is encoded using a motion vector precision,
• wherein the image encoding method,
• constructing the merge candidate list of a target block;
• determining whether the motion vector predictor of the target block from the merge candidate list can be adjusted by a motion vector offset;
• in response to that the motion vector predictor is determined to be adjusted, selecting the motion vector predictor of the target block from one of the two merge candidates included in the merge candidate list, wherein the only two merge candidates in the merge candidate list can be selected as the motion vector predictor and adjusted by the motion vector offset and any remaining merge candidate in the merge candidate list that is not one of the two merge candidates cannot be selected;
• determining the motion vector precision of the motion vector offset for the target block;
• determining the motion vector offset based on the motion vector precision;
• determining a motion vector of the target block by adjusting the motion vector predictor of the target block by the motion vector offset;
• and
• encoding the merge candidate information and the motion vector offset information,
• wherein the merge candidate list includes a spatial merge candidate derived from a spatially adjacent block of the target block, the spatially adjacent block being adjacent to top-right, top, top-left, left, or bottom-left of the target block.