Wednesday, July 31, 2019

Google Photos 4.21 Adds P3 Image Support, Buggy Photo Viewer on Some Devices

When it comes to taking pictures, Android smartphone cameras are usually known to reign supreme in image quality. One major aspect that they all lack, however, is the range of colors that images capture. All images that current Android smartphone cameras capture are saved in the sRGB color space, when many of the smartphone displays we have today support color spaces that are 25% larger than sRGB. Furthermore, pretty much all Android camera sensors are already capable of capturing more-vibrant colors outside the sRGB color space. This means that Android devices are not capturing and displaying all the colors that our own hardware is capable of.

Fortunately, just a few months ago Google announced that wide-color photos are finally coming to Android, and included tips for developers to help make their own apps wide-color ready. The ironic part was that Google’s own Photos app did not support viewing wide-color photos, until their latest 4.21 Google Photos app update, rolling out now.

Google Photos P3 image support

The new Photos update finally introduces wide-color photo-viewing support. In the photo above, the two phones are displaying the same image, but on different versions of the Photos app. The phone on the left is still on Photos version 4.20, while the phone on the right is on Photos version 4.21. The image that’s shown on both phones is a wide-color image of the Android logo in red in the P3 color space, which is a color space that is 25% larger than sRGB. The colors being used in the image are deeper reds in the P3 color space, so without an app with wide-color support, the deeper reds cannot be rendered and appear the same as sRGB red. That’s what’s happening in the comparison above — the older Photos version on the left cannot render the deeper reds of the P3 image, so it just displays it as sRGB red. The Android logo is indistinguishable because the deeper P3 reds both clipped to the deepest sRGB red. Cool, right?

On the software side of things, there’s a lot going on. Color management can get really complicated, but put simply, an sRGB display calibration should be used to properly display normal sRGB content, and when displaying a P3 image, the display should switch from the sRGB display calibration to a P3 display calibration. This is how it’s roughly handled in Android for supporting apps. However, Google’s color management system is still new and barely used in Android, and because of that, not many OEMs have had the opportunity to really test it out to find issues in implementing the color management system that Google introduced in Android 8.1 Oreo. Google Photos will be the biggest app yet to support color management, and users are already facing issues.

In the /r/OnePlus subreddit, many OnePlus phone users that have the updated Photos app are facing issues with a weird green or yellow tint when viewing images in Google Photos [1][2][3]. This happens on every display profile except for the Natural profile, and this is because the Natural profile is the only properly color-managed profile. The Vivid profile reports to support wide gamut switching, but the P3 calibration for the profile has a warmer white point, which is what people are seeing as a green/yellow tint. This is because viewing any image in the newest Photos app update switches the display calibration to the P3 calibration, even if the image isn’t in P3. Ideally, the Photos app should only switch display calibrations to the color space of an image if the image is in a color space other than sRGB. However, always switching to a P3 calibration wouldn’t be an issue if the Vivid display profile’s normal calibration and P3 calibration shared the same white point, which they should. There are also instances of users with issues on the latest update in the Google Photos Help community. In this thread, the issue is likely due to different transfer characteristics (gamma/tone response) between the normal calibration of the Razer Phone 2/Xiaomi Mi 9 and the P3 calibration, resulting in a mess in the sRGB-to-P3 color conversion.

While Google seems to finally be pushing for wider color support, it’s instances like this that show that Google needs to slow down to help OEMs build proper support. The Photos app update works without any issues on Google’s devices, on any of their display profiles. But because of the issues that the update is causing to certain phones, Google might have to roll back this change temporarily, which would be detrimental to the process of adopting wide color. Last month we found that Google is working on wide-color image capture support in the Google Camera app, which we speculate to debut in the cameras of the Pixel 4. The timing of adding P3 image-viewing support to the Photos app seems perfectly ripe for Google, and it only makes sense for other OEMs to follow suit.

Google Photos (Free, Google Play) →

The post Google Photos 4.21 Adds P3 Image Support, Buggy Photo Viewer on Some Devices appeared first on xda-developers.

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