1. A method for processing a video, comprising: performing a target recognition to A first video segments and B first speech segments to obtain M second video segments and N second speech segments, wherein the A first video segments and the B first speech segments are obtained by dividing an inputted video, the M second video segments comprise a first face image of a target character, the N second speech segments comprise a first sound of the target character, A is an integer greater than 1, B is a positive integer, M is a positive integer less than or equal to A, and N is a positive integer less than or equal to B; performing a speech processing to the N second speech segments to obtain N target speech text files, wherein the N second speech segments correspond to the N target speech text files one by one; extracting first representation information of the first face image from the M second video segments to obtain Q pieces of first representation information, wherein Q is an integer greater than or equal to M; determining a second sound matched with the target character according to the Q pieces of first representation information; and merging the second sound with the N target speech text files to obtain N target speech segments, wherein the N target speech text files correspond to the N target speech segments one by one.