imov clip stops for a fraction of a second in between end and start of loop

I created an imov clip of a rain effect and put it on a loop...when it plays back on imovie it looks seamless but when it plays back in a Quicktime player it stops for a fraction of a second in between the end and start of the clip. Is there a fix for that? I don't do this a lot so I'm pretty clueless. Thanks for any assistance.