Each block of texture data elements is encoded as a block of texture data that includes a set of integer values to be used to generate a set of base data values for the block, and a set of index values indicating how to use the base data values to generate data values for the texture data elements that the block represents. The integer values and the index values are both encoded in an encoded texture data block using a combination of base-n values, where n is greater than two, and base-2 values. Predefined bit representations are used to represent plural base-n values (n>2) collectively, and the bits of the bit representations representing the base-n values are interleaved with bits representing the base-2 values in the encoded texture data block.