Method and device for video coding using bidirectional prediction based on motion vector correction

A method of encoding a current block by a video encoding apparatus, the method comprising:

• obtaining a first reference picture and a second reference picture of the current block, with a current picture existing temporally between the first reference picture and the second reference picture;
• determining a first motion vector and a second motion vector of the current block;
• generating a first predictor of the current block by using the first motion vector and the first reference picture, and generating a second predictor of the current block by using the second motion vector and the second reference picture;
• generating a first bidirectional prediction block of the current block by using the first predictor and the second predictor;
• generating a comparative block by using at least one of the first predictor or an intra predictor of the current block;
• searching for a block having a minimum difference from the comparative block, within a preset search range on the second reference picture;
• refining the second motion vector with a vector indicative of a searched block;
• generating a refined second predictor by using a refined second motion vector and the second reference picture;
• and
• generating a second bidirectional prediction block of the current block by using the first predictor and the refined second predictor.

A computer-readable recording medium storing a bitstream generated by a video encoding method, wherein the video encoding method comprises:

• obtaining a first reference picture and a second reference picture of a current block, with a current picture existing temporally between the first reference picture and the second reference picture;
• determining a first motion vector and a second motion vector of the current block;
• generating a first predictor of the current block by using the first motion vector and the first reference picture, and generating a second predictor of the current block by using the second motion vector and the second reference picture;
• generating a first bidirectional prediction block of the current block by using the first predictor and the second predictor;
• generating a comparative block by using at least one of the first predictor or an intra predictor of the current block;
• searching for a block having a minimum difference from the comparative block, within a preset search range on the second reference picture;
• refining the second motion vector with a vector indicative of a searched block;
• generating a refined second predictor by using a refined second motion vector and the second reference picture;
• and
• generating a second bidirectional prediction block of the current block by using the first predictor and the refined second predictor.