1. A conversion device, comprising: a segment processing unit operable to (a) select at least one pair of segments from a plurality of segments constituting original audio data and (b) overlap playback periods of the selected pair of segments; and a generation unit operable to generate after-conversion audio data by arranging the overlapped segments and unoverlapped segments in playback order, the unoverlapped segments being remainders of the plurality of segments, wherein along a time axis of the original audio data, a positional relationship between the overlapped segments and the unoverlapped segments is non-linear.