1. A method, comprising: generating an input block of coefficients in an input color space, wherein the input block includes a first type coefficient and a plurality of second type coefficients; converting the first type coefficient in the input block to an output value in an output color space; determining whether real domain processing is required; converting the input block in a transform domain to an output block of coefficients in the transform domain in an output color space in response to determining that the output value does not require real domain processing.