Methods and Apparatus provide for obtaining a data sequence representative of a three-dimensional parameter space; forming a plurality of coding units by dividing, in three dimensions, the data sequence subject; and generating, for each of the plurality of coding units: (i) a palette defined by two representative values, and (ii) a plurality of indices, each index representing a respective original data point as a value, determined by linear interpolation, to be one of, or an intermediate value between, the representative values, and setting the palette and the plurality of indices for each of the coding units as compressed data.