1. A method for enhancing a video signal comprising: obtaining intensity of luminance values and variation of chrominance values; calculating average and variance of said luminance values and said chrominance values; calculating a luminance-contrast adjustment based upon said luminance values; constructing a luminance curve responsive to a luminance-mapping curve undulating about a point of inflection defined by a neutral point; constructing a final enhancement mapping curve based on values of control factor intensity and said luminance values, wherein both ends of the final enhancement mapping curve may be re-interpolated to provide a soft-clipping effect; constructing a chrominance curve based upon said chrominance values; and applying the luminance curve, the final enhancement mapping curve, and the chrominance curve to the video signal.