{HEAD ~ time information} representing {TAIL ~ time} in the first video within the displayable period, wherein the displayable period is not the entire first video; and 
representing
{ HEAD ~ time information } representing { TAIL ~ time } in the first video within the displayable period , wherein the displayable period is not the entire first video ; and
HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH