It is an MP4. Mysteriously, an .MOV was accepted just now (even though yesterday I tried without success). I am used to iTunes and hadn't heard of the files being limited to m4v. Seeing what you wrote I exported to the lower size, which became a .MOV file, and now it has been accepted. It is now only 145 megs, instead of 1.17 gb which it was. (A bit of a shame, because I do flick them over to my Apple TV box on the large screen TV, so now I suppose it will have less resolution). Thanks very much for your help.