iMovie Projects transfered from iPhone app to Macbook problems

Hello all,

I hve filmed a project in the iMovie app on my iphone. It all looks great on the phone and i even uploaded it direct from there to Youtube with no problem. I wanted to back it up to my Macbook so shared the file in iTunes and saved the project to my desktop. By clicking on it it opens up the project in iMovie on my mac.

Here is the problem. The sound plays perfectly but the picture video keeps jumping as if it's missing frames. Any ideas why this is happening and what can be done to correct it?

Many thanks,

Dean.