Google has launched Duo, a 1-to-1 video calling app, which it hopes will rival Apple's FaceTime.The big difference between the two, is that Google's Duo can be used whether you have an iPhone, iPad of Google Android smartphone or tablet, unlike FaceTime which only works when both devices are manufactured by Apple. Duo, which is free to download and is being rolled out across the world over the next few days, offers some great features too. Knock Knock lets you see a live preview of the caller before you answer the call, which Google says 'gives you a sense of what they're up to and why they want to chat'. Although, this could catch the caller off-guard if they're not aware of this feature.
Furthermore, Duo video calls will continue seamlessly even if you step out of a Wi-Fi area and has to switch onto your 3G/4G connection, meaning you can start a call at home and continue even when you leave the house, without having the call dropping and having to make it again.