It has been possible to make video calls from computers for decades, and from smartphones since there have been front-facing cameras. Yet we stubbornly stick to text and voice messages. Google aims to change all that with Duo, a video calling Android app intended to be fast, simple, and secure. It doesn't bring much that's new, however, and unfortunately it leaves out some things that I consider necessary. For now, you're better off sticking with the ubiquitous Facebook Messenger or, ironically, Google's own Hangouts app. Still, this free, cross-platform service (there's also an iOS app, which I'll be reviewing soon) is worth a try.
One on One
Duo is the first of the products announced at Google I/O 2016 to see the light of day. Neither Allo, Google's smart text messaging app nor the Amazon Echo competitor, Google Home, have been released yet.
Duo is designed for dead simple person-to-person video calling. It's a free download for both Android and iPhone users. I had no trouble installing the app on my Nexus 5X. Google says Duo will work with Android 4.1 and later, though it is designed for Android 6.0—just in time for Android 7.0 Nougat to launch. If you're using the latest version of Android, you have to authorize each of the app's four required permissions one at a time. These are permissions to access your phone's microphone, camera, and contacts and to allow the sending and receiving SMS messages, which are used to invite others to Duo. It takes some tapping, but it also makes the process much safer.
You don't need a Google account to use Duo, but you do have to enter your phone number and authorize the app by inputting the code Google sends via text message. You also have to provide the app access to your Contacts list, as it cannot function otherwise. Facebook Messenger and our Editors' Choice winner Skype do not require accounts, and can be used with just your phone number.
Say That to My Face
Google has said that its main focus with Duo is to make video calling fast and easy, and it certainly is simple to start a call. Just tap the large call button in the center of the screen to be taken to your contacts list. People who have Duo installed appear at the top of the list. Everyone else is listed below, with the option to invite them via SMS or Google Hangouts.
The app is designed for one-on-one communication, so you'll have to look to Google Hangouts or Skype for group video chat. Both of those services can support up to 10 participants. Buttons on the side mute your microphone and toggle between your phone's front- and rear-facing cameras. Everything in the app is snappy and responsive, which is a pleasant surprise in a video calling app. I really like how tapping the preview bubble in the bottom left-hand corner toggles between a full-screen view of your caller's video and your own. It's a smooth and seamless animated transition that speaks to the app's overall quality.
Finding someone else to call is, perhaps, Duo's biggest challenge. Most people have Google accounts, and they definitely do if they're Android users, since the Google Play store requires that you create an account. But not everyone has downloaded Duo.
If you have a Google Account, you can very likely be reached via Google Hangouts, at least for text messages, and usually for video as well. This is similar to the way anyone with a Facebook account can automatically be reached via Facebook Messenger, even if they haven't actually signed up for the Messenger service. Hangout messages have the benefit of appearing in many different locations, including the Hangouts app (there's also a Google Hangouts app for iPhone), desktop notifications through Google Chrome, Gmail, and other places. The Android Hangouts app also serves as an entire SMS replacement, thanks to Google Voice, making it more capable than Duo. Duo, like any other add-on messenger—WhatsApp, Kik, Line, and so on—requires buy-in from users. I wish that Google had instead made its myriad Hangouts users all directly accessible via Duo. As it is, you might have to do some convincing to get your friends on board.
If you've already made or received calls with Duo, the contacts in question appear on the main screen for fast calling. If you missed a call, that person who called is front and center with a red bounce icon to make calling back easy.
When you tap to make a call, the app switches into Knock Knock mode. This feature plays a live video preview to the recipient of your call. They can see you but not hear you, and you can't see them at all until and unless they answer. It's sort of like peeking through a peephole in your door to see who's knocking.
Knock Knock is a great feature, and it's one I am sure we'll see emulated elsewhere. But I really don't like how answering calls works. If you reject a call, it ends immediately. There's no way to use Duo to say "call me back in a few minutes" or to continue with with video turned off. In fact, there's no way to use Duo without turning on your video. With Snapchat you can choose to accept a video call just with text or audio. Most phones have a similar feature for voice calls, letting you tap to decline a call with a text message, for example. If you miss a call, you can send a Hangouts or SMS message from Duo's notification, but that's not nearly as handy. Google's drive to create the simplest video calling app seems to have come at the price of useful features, at least in this case.
Duo clearly informs callers that their likenesses are appearing with Knock Knock, but it doesn't tell recipients that their cameras aren't on until they accept the call. I could easily see call recipients getting confused and panicking at the mistaken thought that their phones are transmitting video without permission. Google would do well to make this clearer.
When you accept a Duo call, video from the caller fills the screen, and it looks and sounds excellent. The app is able to seamlessly switch between Wi-Fi and cellular data to make sure your calls don't drop, although you can change this feature in the app's settings. My Duo calls looked and sounded very good over our office FiOS connection, and I was surprised by how little latency I experienced.
Unfortunately, Google's claim that the service works in all network conditions didn't pan out in my testing over Wi-Fi. Several calls couldn't connect, and in a few calls the app paused video because of poor network conditions. I consider our fast PC Labs FiOS Wi-Fi connection to be a best-case scenario, so I'm disappointed by this spotty performance. I found that calls connected faster and more reliably over T-Mobile LTE. Your mileage, of course, may vary.
Note that your iPhone-using friends will have a slightly different experience. If their phone is in use, the Knock Knock screen works just like on Android. If their iPhone is locked, they'll receive a notification with accompanying ringing and vibration. They won't see the Knock Knock screen, and swiping the notification opens the phone and automatically accepts the call.
Note, too, that unlike Viber, Duo offers no way to hand off calls between your phone and a desktop computer. In fact, Duo has no desktop component. It only exists for phones.
Leave Me Alone
A quick note on security: In the app's announcement, Google assures users that all calls made through Duo are encrypted end-to-end. But details about the protocol used aren't available. Encryption is great, but so is transparency. When Google announced its messaging app Allo, the company said it would use the Signal encryption protocol, which powers the Signal messaging and voice app. That's the kind of detail I want.
Not everyone who has a phone is a good person, so it makes sense that Duo lets you block contacts from whom you'd rather not receive calls. Requiring that users have the person they wish to call in their contacts is already a good deterrent, but a block list is an even better tool. Unfortunately, you have to access the list from the Settings menu. I'd rather Google include a Block button on the incoming call screen or in the call itself.
Worth a Look
With Duo, Google delivers on its promise for a fast and simple video calling experience. It takes just seconds to set up, and making a call on the service couldn't be simpler. With smart features like Knock Knock, Duo is trying to make people more comfortable with video calls.
But Google's dedication to simplicity means that Duo lacks some critical features. There's no way to accept a call without turning on your video, and no way to decline a call with a message. And while Knock Knock is clever, it needs to be clearer about when your video can and cannot be seen. Finally, I found making and receiving calls a bit hit-or-miss, which makes me wonder if Google really can deliver on the promise that Duo will work seamlessly in less-than-ideal network environments. With all that in mind, I recommend that Android users stick with Editors' Choice-winning services like Skype and Facebook Messenger.