I first figure out the phone. my Iphone 6 is not 4K its HD1080P. so anything above 1080 is a bonus. for the PC I use an editor, quicktime is needed on MOV not mp4 just the codecs and the editor normally supplies it. so @clionac has offered some info.
We still have no clue the win pc thing. Powerdirector for me works (Smiles)