A normal video data acquisition section acquires, as normal video data, a plurality of pieces of video data respectively assigned to a plurality of light sources in normal display from an input video signal A computing section performs a predetermined computation on the plurality of pieces of video data included in the normal video data to generate auxiliary video data used in place of the normal video data in auxiliary display. A selection section performs, in accordance with an instruction from a control section, a selection process for providing any one of the normal video data and the auxiliary video data to a modulation driving section.