decoding, with the decoding apparatus, a residual block of a coding block from a bitstream;

determining, with the decoding apparatus, a plurality of weight prediction parameter candidates for the coding block based on number information signaled in a unit of a sequence of the bitstream, the sequence being a higher unit than the coding block;

determining, with the decoding apparatus, a weight prediction parameter of the coding block from the weight prediction parameter candidates based on index information signaled in the unit of the coding block;

obtaining, with the decoding apparatus, a prediction block of the coding block by obtaining a second prediction sample of the coding block; and

reconstructing, with the decoding apparatus, the coding block based on the prediction block of coding block and the residual block of the coding block,

wherein the second prediction sample is obtained by applying the weight prediction parameter to a first prediction sample of the coding block resulting from performing inter prediction on the coding block,

wherein only the weight prediction parameter of the coding block is used in a step of obtaining the prediction block of the coding block,

wherein a remainder of the weight prediction parameter candidates except for the determined weight prediction parameter is not used in the step of obtaining the prediction block of the coding block, and

wherein a number of the weight prediction parameter candidates is determined based on the number information.