1. A display control apparatus comprising: a synthesizing unit configured to synthesize multiple pieces of image data to generate synthesized image data; an image quality adjustment unit configured to carry out image quality adjustment for the synthesized image data output from the synthesizing unit; a format discrimination unit configured to discriminate a format of each of the multiple pieces of image data; a determination unit configured to determine referenced image data for the image quality adjustment among the multiple pieces of image data based on discrimination results in the format discrimination unit; and a control unit configured to control the image quality adjustment unit so as to carry out the image quality adjustment for the synthesized image data using an image quality adjustment parameter suitable for the referenced image data determined by the determination unit.