 The effect is that immediately recurring symbols are replaced by zero symbols (long runs of "any" arbitrary symbol thus become runs of zero symbols), while other symbols are remapped according to their local frequency.Much "natural" data contains identical symbols that recur within a limited range (text is a good example).As the MTF transform assigns low values to symbols that reappear frequently, this results in a data stream containing many symbols in the low integer range, many of them being identical (different recurring input symbols can actually map to the same output symbol).