As a result, the child frame video can be switched freely between display and {TAIL ~ non display} within {HEAD ~ the range} of the displayable time 
As a result , the child frame video can be switched freely between display and { TAIL ~ non display } within { HEAD ~ the range } of the displayable time
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH