Method and apparatus for color space conversion

Methods and apparatuses for converting color components in one space to those in another space. In one aspect of the invention, a method for vector conversion including: loading a first vector of components into a vector register; generating a first vector of indices in a vector register, each index of the first vector of indices being one of the first vector of components, at least one component in the first vector of components being replicated as a plurality of duplicated indices in the first vector of indices; looking up simultaneously a first vector of data items from a plurality of look up tables using the first vector of indices; and summing up at least one subset of the first vector of data items into at least one component of a second vector of components.