Techniques for selecting a luminance value for color space conversion are disclosed. Techniques include determining values for Cb and Cr from values for R′, G′, and B′; producing a reconstructed Cb* value and a reconstructed Cr* value by processing the Cb and Cr values; and determining a plurality of Y′ value options from the values for Cb* and Cr*. A Y′ output value may be selected based on the plurality of Y′ value options.