1. A method of decoding a video signal having a current block to be decoded with a decoding apparatus, comprising: obtaining, from the video signal, residual samples of a current block and index information relating to the current block, the index information being signaled to select a collocated picture from a plurality of previously decoded pictures, the collocated picture being representative of a picture including a collocated block which is used to derive a temporal motion vector candidate of the current block; obtaining a spatial motion vector candidate from a spatial neighboring block of the current block; selecting, based on the index information, the collocated picture relating to the temporal motion vector candidate of the current block from the plurality of the previously decoded pictures; obtaining the temporal motion vector candidate from the collocated block included in the selected collocated picture; generating a motion vector candidate list by arranging the spatial motion vector candidate and the temporal motion vector candidate in order of priority; deriving a motion vector predictor based on the motion vector candidate list and a candidate index of the current block, the candidate index specifying one of motion vector candidates included in the motion vector candidate list; obtaining prediction samples of the current block by using the motion vector predictor; and reconstructing the current block by using the residual samples and the prediction samples.