For iTunes rented movies, once downloaded to your computer, you have only 30 days to watch it. After 30 days, the movie will disappeare automatically. And when you start to play the movie, you have only 24 hours to watch it. Moreover, due to the DRM protection, we cannot enjoy iTunes rented movies on any other media devices like Android, Windows Phone, Nokia, PSP, Zune, Blackberry, etc.

If you want to get rid of these restrictions to enjoy iTunes rentals movies anytime or anywhere as you like, watch and follow this video tutorial, and you can achieve it easily by converting iTunes M4V movies to MP4, AVI, MPG, 3GP, etc.

https://www.youtube.com/watch?v=vR2IqeBe530