CPC Class H04N

An inter prediction method according to the present invention comprises: a step for deriving reference motion information related to a unit to be decoded in a current picture; and a step for performing motion compensation for the unit to be decoded, using the reference motion information that has been derived. According to the present invention, image encoding/decoding efficiency can be enhanced.

Techniques are described to use a reference motion vector to reduce the amount of bits needed to encode motion vectors for inter prediction. One method includes identifying a candidate motion vector used to inter predict each of a plurality of previously coded blocks to define a plurality of candidate motion vectors, determining a distance between the previously decoded block associated with the candidate motion vector and a current block, determining a popularity value for each candidate motion vector based on a set of previously coded pixels associated with the candidate motion vector, and ranking the candidate motion vectors according to a priority value for each candidate motion vector. The priority value, based on the distance and the popularity value associated with the candidate motion vector, is used to select a reference motion vector from the candidate motion vectors that is used to encode the motion vector for the current block.

Provided is an inter prediction method including determining a collocated block of a current block of a current image from among blocks of an image that is restored prior to the current image; preferentially checking whether a first reference list from among reference lists of the collocated block is referred to and selectively checking whether a second reference list is referred to according to whether the first reference list is referred to; based on a result of the checking, determining a single collocated reference list from among the first reference list and the second reference list; determining a reference block of the current block by using motion information of the collocated reference list; and performing inter prediction on the current block by using the determined reference block.