  The play operator minimalizes the total variation on intervals $[0,T], T> 0$,
of functions approximating uniformly given regulated function with given
accuracy and starting from a given point. In this article we link the play
operator with so called truncated variation functionals, introduced recently by
the second-named author, and provide a semi-explicit expression for the play
operator in terms of these functionals. Generalisation for time-dependent
boundaries is also considered. This gives the best possible lower bounds for
the total variation of the outputs of the play operator and its Jordan-like
decomposition.
