An encoding method, a decoding method, an encoding apparatus, a decoding apparatus, for a video image. The encoding method includes: determining an optimal merged neighboring block for a current block based on a motion vector merging technology; determining, based a prediction direction of the optimal merged neighboring block, a motion vector derivation mode that needs to be used by a decoder; correcting a motion vector of the current block based on the motion vector derivation mode; and determining a residual between a predicted value and an original value of the current block based on the corrected motion vector, thereby encoding the current block. According to the technical solutions, a more accurate predicted value is obtained by correcting the motion vector, and a smaller residual is generated.