1. An image processing apparatus comprising: a microcomputer configured to: separate input frame data into a subject layer and a background layer; and generate combined image data based on the input frame data according to priorities of the subject layer of the input frame data, the background layer of the input frame data, a background layer of previous input frame data, and a subject layer of the previous input frame data, wherein an aspect ratio of the combined image data is different from the input frame data, and the subject layer of the input frame data has a higher priority than the background layer of the previous input frame data.