Yes and no.
No - because it is technically a violation of the 'licensing agreement' that you (supposedly) enter into when you purchase a DVD. The MPAA would say that you're not buying a movie, but you're buying a license to watch the DVD version movie on one player at a time for private use. You are not supposed to rent out your DVD or charge people to watch it (because the MPAA would want a cut of that money). The licensing agreement also explicitly forbids copying. It could also be argued that circumventing the copy protection on the DVD violates the DMCA.
Yes - because the MPAA isn't incurring any monetary loss or damages if you view a copy of the movie you already bought on a device you own. Forms of copying (back ups) have been declared as fair use and no judge worth their salt would find against you for transferring a movie you already paid for to your phone for your own use.
Short story: If the MPAA thought they could make money by suing you then they would... but since they are only losing ~$14 each time someone makes a copy for their phone *for their own personal use* (not for giving away to people or distribution).... it doesn't make financial sense for them to hire a $200/hr lawyer to go after you.