Most forms of DRM (Digital Rights Management) will prevent playing movies on unauthorized devices or from remote storage hosted on wireless drives or NAS drives(Seagate Wireless, Seagate Wireless Plus, Seagate Central or Seagate Personal Cloud).
Movies purchased from iTunes can be streamed to iOS 6 and iOS 7 devices which were authorized from remote storage (the video could be selected in Seagate Media App and would be played in a Safari browser), however in iOS 8 this has stopped working. A bug has been filed with Apple, however this functionality has not been restored. Therefore, DRM protected movies purchased on iTunes can no longer be played on devices running iOS 8.