Yep, Arm River track it is. 4 adults and 6 kids 'practicing' for the Overland Track next year (ie, to see how the kids might cope with the walking/carrying/pitching/etc, and to be sure we've got all the right gear, and that we can all get along OK).
The view of Lake Ayr and particularly of Mt Oakleigh in the video are a bit of a give away.