During recording, {HEAD ~ a plurality} of {TAIL ~ consecutive image frames} is separated into a plurality of groups, in each of which the image frames are intraframe or interframe compression coded to digital image information 
of
During recording , { HEAD ~ a plurality } of { TAIL ~ consecutive image frames } is separated into a plurality of groups , in each of which the image frames are intraframe or interframe compression coded to digital image information
OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL 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 OTH OTH OTH OTH