public AppleTag(IsoUserDataBox box) { if (box == null) { throw new ArgumentNullException("box"); } meta_box = box.GetChild(BoxType.Meta) as IsoMetaBox; if (meta_box == null) { meta_box = new IsoMetaBox("mdir", null); box.AddChild(meta_box); } ilst_box = meta_box.GetChild(BoxType.Ilst) as AppleItemListBox; if (ilst_box == null) { ilst_box = new AppleItemListBox(); meta_box.AddChild(ilst_box); } }