My memory is playing tricks on me. I'm sure I read in a VCR manual that its resolution was 312.5 lines (I'm in UK so 625 lines). I had assumed this meant that VCR showed the same field twice in a frame to save tape. But I can't find anything to say if they do or don't. All I can find is that VCR tapes are 240/250 lines but I think that is something different again.