Further, every time the child frame video is switched freely between display and non display, {HEAD ~ the child frame video} can be synthesized for {TAIL ~ its display} at an appropriate position 
Further , every time the child frame video is switched freely between display and non display , { HEAD ~ the child frame video } can be synthesized for { TAIL ~ its display } at an appropriate position
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH REL REL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH