The values will typically not change while waiting for control requests
and not processing the demux and outputs. Even if the values do change
(e.g. due to a seek request), the demux needs to be called to recompute
the updated values: see demux_Control() calls in MainLoopStatistics().

Note that the intrinsic computational savings from this commit are
probably negligible. The interesting aspect is the removal of one
wake-up source within the input control loop. This commit does not
remove nor add any wake-up however.