/// <summary> /// Create and add a pair of empty composition tables (not used in fragment mode) /// </summary> public override void Prepare() { if (!_childrenAdded) { stts sample_to_time = new stts(); AddChild(sample_to_time); ctts composition_to_time = new ctts(); // spec says not needed, but every file I inspect has an empty one. AddChild(composition_to_time); _childrenAdded = true; } }