During a rewind operation, a reference picture for {HEAD ~ a group} of {TAIL ~ pictures} is decoded and stored into a reference frame buffer 
During a rewind operation , a reference picture for { HEAD ~ a group } of { TAIL ~ pictures } is decoded and stored into a reference frame buffer
OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH