From within the phone app, you'll be able to initiate a video call from the call history or search. So, for making a video call via Google Duo, the user of the Android phone needs to have the Duo application installed in their phone. When the video call is placed, it'll go through your carrier's ViLTE service (video over LTE).
Google has again updated its Play Store app, and now it reaches version number 8.3.42, now this version does not bring the features we talked about earlier in our tear-down of the version (8.3.41). So in this case video calls are routed through a high quality video channel. Google has further assured that it will be adding a new feature which allows users to switch from voice to video calls without disconnecting the app. In March, the app gained audio calling support, so it's not a one-trick pony anymore.
Google Duo's video-calling feature will be integrated into the Phone, Contacts and the Messaging apps on Android system, according to a new post from Google.More news: Seismic activity detected near North Korean nuclear test site - USGS
As for supported devices, you and whoever you are video calling only have a handful to choose from. Google also noted that the new feature will also be available on the newly launched Pixel 2 and Pixel 2 XL as well.
Lastly, to try the integration using ViLTE, you and whoever you're video calling have to be on Verizon, a Google spokesperson confirmed with VentureBeat. Thankfully, Google's carrier partner Verizon is offering just that. For now though, its availability is still extremely limited.