1. A display controller for performing multimedia processing which is encoding or decoding processing of video data, still image data, or sound data, the display controller comprising: a host interface which performs interface processing between the display controller and a host processor; a memory into which a multimedia processing program is loaded, when the host processor has read the multimedia processing program from a multimedia processing program group stored in a host memory and transmitted the multimedia processing program to the display controller; a built-in processor which executes a software processing portion of the multimedia processing assigned to software processing based on the loaded multimedia processing program; and a first hardware accelerator which executes a hardware processing portion of the multimedia processing assigned to hardware processing.