A method of decoding a video signal according to the present invention may include: determining whether or not change in brightness is present between a current video including a current block and a reference video of the current video; when it is determined that change in brightness is present between the current video and the reference video, determining weight prediction parameter candidates of the current block; determining a weight prediction parameter of the current block on the basis of index information specifying any of the weight prediction parameter candidates; and performing prediction for the current block on the basis of the weight prediction parameter.