Abstract: Examples relate to a method, an apparatus and a computer program for processing an almost-periodic input signal comprising a plurality of signal portions of varying duration, and to a system comprising such an apparatus and a visual output device. The plurality of signal portions are characterized by a common signal shape. The method comprises assigning the plurality of signal portions to a plurality of sets of signal portions. Each set of signal portions comprises two or more signal portions. The method comprises adjusting a duration of at least a subset of the signal portions such that the signal portions of a set have the same duration. The method comprises superimposing the two or more signal portions of a set within a combined output signal.