Method for encoding and decoding motion information and device for encoding and decoding motion information
A method of decoding motion information according to an embodiment includes: determining a base motion vector of a current block; determining a primary differential motion vector for the current block based on information obtained from a bitstream from among one or more primary differential motion vector candidates classified according to a disparity distance and a disparity direction; and determining a motion vector of the current block by applying the primary differential motion vector to the base motion vector.
1. A method of decoding motion information, the method comprising:
obtaining a first motion vector difference for a first direction by parsing a disparity distance index and a disparity direction index from a bitstream;
if a prediction direction of a current block corresponds to a bi-direction, deriving a second motion vector difference for a second direction, based on the first motion vector difference, a POC (picture order count) of a current picture, a POC of a first reference picture, and a POC of a second reference picture;
obtaining a first motion vector for the first direction using the first motion vector difference and a first base motion vector for the first direction;
obtaining a second motion vector for the second direction using the second motion vector difference and a second base motion vector for the second direction, and
reconstructing the current block using the first motion vector, the first reference picture, the second motion vector and the second reference picture.
2. A method of encoding motion information, the method comprising:
obtaining a first motion vector difference for a first direction by using a first motion vector of a current block for the first direction and a first base motion vector for the first direction;
if a prediction direction of the current block corresponds to a bi-direction, deriving a second motion vector difference for a second direction, based on the first motion vector difference, a POC (picture order count) of a current picture, a POC of a first reference picture, and a POC of a second reference picture; and
generating a bitstream including a disparity distance index and a disparity direction index, the disparity distance index and the disparity direction index representing the first motion vector difference.