Method and apparatus for encoding a motion vector, and method and apparatus for encoding/decoding image using same

An apparatus of predicting a current motion vector of a current block in a current frame for predictively decoding the current motion vector, the apparatus comprising:

• a prediction candidate selector configured to select one or more motion vector prediction candidates from among blocks in the current frame and a block in a reference frame other than the current frame to determine a predicted motion vector corresponding to the current motion vector;
• and
• a predicted motion vector determiner configured to determine the predicted motion vector among the one or more motion vector prediction candidates,
• wherein the prediction candidate selector comprises:
• means for deriving one or more first motion vector prediction candidates from motion vectors of one or more blocks adjacent to the current block in the current frame, and
• means for deriving a second motion vector prediction candidate from a motion vector of the block located in the reference frame, wherein the block, from which the second motion vector prediction candidate is selected, in the reference frame is derived based on a position of the current block in the current frame,
• wherein the prediction candidate selector is configured to select one of the first motion vector prediction candidates from upper blocks adjacent to the current block, and one of the first motion vector prediction candidates from left blocks adjacent to the current block,
• wherein the prediction candidate selector is configured to determine the predicted motion vector among the one or more motion vector prediction candidates based on a prediction candidate identification flag extracted from a bitstream.