Duo is a one-to-one video calling app for everyone – designed to be simple, reliable and fun so you never miss a moment.
Features:
Simple interface
Pick a loved one and jump right in, with a simple interface that brings video to the forefront.Knock Knock
See the caller before you pick up with Duo’s live preview feature.High quality video
Experience faster and more reliable video calls whether you’re on Wi-Fi or on-the-go.Cross-platform
Video call all your friends across Android and iOS with just one simple app.https://duo.google.com
Duo Versus FaceTime
The Duo app is downloadable and free through Google’s Play store and Apple’s App Store. When you open the Duo app, there is just one button: video call. Tapping that loads your contacts list, and from there you can choose whom to call.
Duo starts streaming video to a recipient as soon as the call is placed, meaning the person you are calling will be able to see you waving or making faces before he or she picks up. Google calls this feature Knock Knock. It can be disabled in case you have friends who are likely to make inappropriate hand gestures.
With FaceTime, you place a call directly through the iPhone’s contacts list or through the separate FaceTime app. The recipient does not see the video streaming until after the call is answered.
https://play.google.com/store/apps/details?id=com.google.android.apps.tachyon&hl=en
http://www.nytimes.com/2016/08/18/technology/personaltech/google-duo-video-calling-app-facetime.html?_r=0
