A video controller and method for performing tone-mapping of high-dynamic-range (HDR) video are provided. The video controller includes: a color-space converter, arranged to receive an input high-dynamic-range (HDR) video signal and perform a color space conversion on the input HDR video signal to obtain a first video signal having a first gamma curve; a de-gamma unit, arranged to apply a second gamma curve on the first video signal to compensate the first gamma curve to obtain a second video signal; a first histogram calculator, arranged to calculate a first histogram of a current frame of the second video signal; and a tone-mapping unit, arranged to apply a tone-mapping curve on the current frame of the second video signal according to a histogram of a previous frame of the second video signal to generate an output video signal.