IFA 2019 is underway, so we're seeing a plethora of smartphone device makers unveil their latest offerings. So far, none of the new smartphones that have been announced have a high refresh rate display. Just this year alone, we've seen the Nubia Red Magic 3, ROG Phone II, and OnePlus 7 Pro come out with 90Hz or higher refresh rates. I crowned the OnePlus 7 Pro the best smartphone in the first half of 2019, in large part due to its 90Hz display. The upcoming Google Pixel 4 smartphones are also rumored to have 90Hz displays, which we can now confirm thanks to a comment left by a Googler in the Android 10 source code.

Google finished uploading the source code for the Android 10 release the other day, and I've spent some time digging through the source code to look for under-the-hood changes that Google hasn't advertised. While examining the changes made to Android's SurfaceFlinger, a system service responsible for compositing app and system surfaces into a single buffer for the display controller, I spotted several commits related to display refresh rate. For example, one commit describes content-based fps detection while another describes the implementation of an overlay to show when the device is running at 60Hz versus 90Hz. Given that Google makes changes to AOSP all the time to accommodate a growing segment of devices from OEMs—and there's definitely an upward trend in smartphones coming out with high refresh rate panels—these commits to the Android 10 source code weren't proof that the next Pixel will have a 90Hz display. That is, however, until I stumbled upon a comment left behind in a commit that has since been removed but can still be viewed by going through the commit history.

Google Pixel 4 90Hz confirmed

Let me explain what you're looking at here. This code adds an enable/disable flag to toggle 90Hz, and according to the commit description, it's only intended to be used temporarily until the proper solution is implemented (which happened less than a month later). The comment above the if...else statement reveals that the switch to toggle 90Hz "should only be available to P19 devices," where P19 is almost certainly the Pixel 2019. Since the Pixel 3a series has already been released without a 90Hz display, that means the Googler is definitely referring to the upcoming Pixel 4 series.

Since we learned that these refresh rate-related code changes are intended primarily for the Google Pixel 4, we went back and examined other changes to SurfaceFlinger to see if we could learn more. We discovered that Google intends to expose the refresh rate overlay as a Developer Option in Android 10. The overlay will be shown underneath the clock in the status bar, and it will show up as a thin rectangle that's either "red" for 60Hz or "green" for 90Hz. Lastly, we also learned that Google is preparing to detect when a video is playing so the Pixel 4 can automatically adjust the refresh rate.

Last month, a source told 9to5Google that the Google Pixel 4 will feature a 90Hz "Smooth Display." The larger XL model is expected to have a 6.3-inch 1440p 90Hz OLED display, while the non-XL model is expected to have a 5.7-inch 1080p 90Hz OLED display. The XL model is expected to have a 3,700mAh battery versus the 2,800mAh battery on the non-XL model. It remains to be seen if the smaller 2019 Pixel will have decent battery life when using the 90Hz display mode, but we won't find out until the phone is released.

The Google Pixel 4 is also rumored to have 6GB of RAM and dual rear cameras with one being a 16MP telephoto camera. We have corroborating evidence for the Pixel 4's telephoto camera, so it's likely that Google won't add a dedicated ultra wide-angle lens as some have wanted. Google confirmed that the late 2019 Pixel will have Face ID-like hardware and a Soli radar for "Motion Sense" air gestures (though the gestures only work in select countries). Both smartphones will launch with Android 10 now that the new Android OS has reached stable status. We also now definitively know the design of the Pixel 4 smartphones thanks to Google themselves and two separate hands-on leaks this past week. Google's 2019 Pixel smartphones are expected to launch next month, and as we get closer to the launch date, we're bound to uncover more details.

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