A data encoding method for encoding an array of data values as data sets and escape codes for values not encoded by the data sets, an escape code including a unary coded portion and a non-unary coded portion, the method including: setting a coding parameter defining a minimum number of bits of a non-unary coded portion; adding an offset value of 1 or more to the coding parameter to define a minimum least significant data portion size; generating one or more data sets indicative of positions, relative to the array of data values, of data values of predetermined magnitude ranges, to encode the value of at least one least significant bit of each data value; generating respective complementary most-significant data portions and least-significant data portions; encoding the data sets; encoding the most significant data portions; and encoding the least-significant portions.