1. A method for generating a piecewise inter-layer predictor, the method comprising: accessing a first video signal with a first dynamic range; accessing a second video signal representing the first video signal in a second dynamic range, wherein the second dynamic range is lower than the first dynamic range; and generating with a processor a piecewise inter-layer predictor to predict pixels of the first video signal based on pixels of the second video signal, wherein generating the piecewise inter-layer predictor comprises: generating a first set of pre-computed values based on computing b n , wherein b denotes a pixel value in a frame of the second video signal in the range [0, K−1], n is an integer larger than 0, K=2 M , and M denotes the bit depth of the second video signal; for a frame of the second video signal, using the processor to: generate a histogram for the frame of the second video signal, wherein generating a histogram value h b comprises computing h b = ∑ i = 0 P - 1 ⁢ ( s ji == b ) , wherein for the j-th frame in the second video signal, P denotes the total number of pixels under consideration in the frame, and s ji denotes pixel values of the second video signal in the frame; generate a second set of pre-computed values comprising: w b = ∑ i = 0 P - 1 ⁢ ⁢ ( ( s ji ⩵ b ) · v ji ) and w b 2 = ∑ i = 0 P - 1 ⁢ ⁢ ( ( s ji ⩵ b ) · v ji 2 ) , wherein v ji denotes pixel values of the corresponding j-th frame in the first video signal; and generating coefficients of at least one polynomial in the piecewise predictor using the first set and second set of pre-computed values and the histogram.