The amount of data deriving apparatus

A data amount derivation apparatus includes: a first calculator configured to derive, for one series of parallelized mapping signals, amount of data in each frame period for a frame into which the parallelized mapping signals are mapped; and a second calculator configured to sum up amounts of data in N frame periods, where N is an integer, and to derive the resulting summation value as the amount of data to be mapped into the frame, each of the amounts of data in each of the frame periods being derived by the first calculator.