1. A display controller that performs multimedia processing, the multimedia processing being encoding or decoding processing of video data, still image data, or sound data, the display controller comprising: a host interface that 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 the host processor transmitted the multimedia processing program to the display controller; a processor that executes a software processing portion of the multimedia processing assigned to software processing based on the multimedia processing program loaded in the memory; and a first hardware accelerator that executes a hardware processing portion of the multimedia processing assigned to hardware processing, the processor being released from a reset state when the host processor has directed reset release, and executing the multimedia processing program after being released from the reset state, the multimedia processing program being an encoding processing program that executes a software processing portion of encoding processing of the video data; the first hardware accelerator performing discrete cosine transform processing, quantization processing, inverse quantization processing, inverse discrete cosine transform processing, motion compensation processing, and motion estimation processing as the hardware processing portion; and the processor performing variable length code encoding processing as the software processing portion.