1. A method comprising: using a series of butterfly structure operations on fixed-point numbers to apply a transform to a vector of source coefficients in order to generate a vector of transformed coefficients; wherein transformed coefficients in the vector of transformed coefficients are approximations of values that would be produced by transforming the vector of source coefficients using an ideal inverse discrete cosine transform; and causing a media presentation unit to output audible or visible signals based on transformed coefficients in the vector of transformed coefficients, wherein differences between results generated by one of the butterfly structure operations and results that would be generated by an equivalent butterfly structure operation using unlimited precision arithmetic are centered around zero and positive differences and negative differences are of approximately equal magnitude.