Move over FaceTime: Google releases video calling app Duo

This image provided by Google shows its video chatting app on mobile devices.  (Google via AP)

Move over, FaceTime and Skype. Google has released a one-to-one video calling app called Duo.

Unlike Google's video chatting app Hangouts, Duo is for smartphones only and offers simple one-to-one calling rather than video conferencing.

And it seems Google's key word to describe the app is "simple."