1. A method of determining motion vectors and a reference picture index for a current block in a picture to be decoded, comprising: obtaining first and second motion vectors and a reference picture index of blocks other than the current block, the other blocks neighboring the current block; determining first and second motion vectors of the current block using the first and second motion vectors of the other blocks, the determining including applying a median operation to the first motion vectors of the other blocks and applying a median operation to the second motion vectors of the other blocks; and determining a reference picture index of the current block using the reference picture indices of the other blocks.