That encoding is not the time but a duration (or part of a time interval), i.e. 23 hours, 12 minutes and 48 seconds not 11:12:48 PM. Nothing I am aware of handles that directly in Qt. You could disassemble it with a QRegularExpression and build a number of seconds fairly easily, but there are quite a few variations you need to be careful of in the standard. You also need to be careful if you are adding durations to absolute times around daylight savings changes.