The position designator 110 determines the displayed position of the child frame video in accordance with displayable time information of {HEAD ~ the child frame video} and information on the displayed area or displayable area depending on time, included in the data for {TAIL ~ display} 
The position designator 110 determines the displayed position of the child frame video in accordance with displayable time information of { HEAD ~ the child frame video } and information on the displayed area or displayable area depending on time , included in the data for { TAIL ~ display }
OTH OTH OTH 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 OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL