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