Method for encoding/decoding image, and device therefor

An image encoding method comprising:

• determining at least one prediction block included in a current picture from among pictures forming an image;
• determining a first motion vector related to a current prediction block from among the at least one prediction block;
• determining a first reference block included in a first reference picture, based on the first motion vector;
• determining a second reference block included in a second reference picture, based on a location of the first reference block;
• and
• encoding the current picture by performing inter prediction on the current prediction block by using at least one of the first reference block and the second reference block, wherein the second reference picture comprises a prediction value of the first reference picture.

An image decoding apparatus comprising:

• a decoder configured to determine at least one prediction block included in a current picture from among pictures forming an image, and determine a first motion vector related to a current prediction block from among the at least one prediction block;
• and
• a reference block determiner configured to determine a first reference block included in a first reference picture, based on the first motion vector, and determine a second reference block included in a second reference picture, based on a location of the first reference block,
• wherein the decoder is further configured to decode the current picture by performing inter prediction on the current prediction block by using at least one of the first reference block and the second reference block, and
• the second reference picture comprises a prediction value of the first reference picture.