Method for encoding and decoding motion information, and apparatus for encoding and decoding motion information

An apparatus of decoding motion information, the apparatus comprising:

• an obtainer configured to obtain, from a bitstream, information about a precision of a pixel unit in a predetermined mode, information indicating a disparity distance for a current block, and information indicating a disparity direction for the current block;
• and
• a motion information decoder configured to:
• if the precision of the pixel unit is a predetermined precision, determine a first disparity distance based on the obtained information indicating the disparity distance;
• if the precision of the pixel unit is not the predetermined precision, determine a second disparity distance based on the obtained information indicating the disparity distance;
• and
• if the current block is bi-predicted:
• determine a first motion vector for a first list of the current block by changing a first base motion vector for the first list by a first offset, wherein the first offset has a size corresponding to the first disparity distance or the second disparity distance, and a sign of the first offset corresponds to the information indicating the disparity direction;
• determine a second offset by scaling the first offset based on a difference between a picture order count (POC) of a current picture and a POC of a first reference picture in the first list, and a difference between the POC of the current picture and a POC of a second reference picture in a second list;
• and
• determine a second motion vector for the second list of the current block by changing a second base motion vector for the second list by the second offset,
• wherein the second disparity distance is larger than the first disparity distance.