In addition to the new Allo messaging app at its I/O developer conference, Google introduced a new video calling app called Duo.

Built by the team behind WebRTC, Duo is designed to make video calls more reliable even on the slowest Internet connections.

Duo is based on your phone number (no new account needed) and is a cross-platform app that will work on both iOS and Android. The app will be available this summer.

Google says people don’t place as many video calls with their friends and family because connections can sometimes be spotty and drop. Duo uses a new protocol called QUIC that’s supposed to be more robust than any other video calling infrastructure out there.

In one demo, a Google presenter showed off how a person immediately shows up on the call connection screen, even before you pick up.

Like Allo, Duo is end-to-end encrypted for secure communications.

As great and cross-platform as Skype is, the mobile experience (in my opinion) has always been mediocre. I always get dropped calls or the video call quality is poor.

Assuming Google’s not BSing us and Duo really does work well on slow connections, the app could be a real game changer.