By Google is getting serious about HDR screenshots, which means you can now snap screenshots of HDR content.
Most users capture screenshots on Android to share what they see with others, and Android is well-suited for this task. Until recently, Android didn’t need to allow taking HDR screenshots because the great majority of the information we saw was in SDR. As HDR content becomes more popular, individuals will surely take screenshots including HDR elements. Thankfully, Google will finally provide HDR screenshot support in this year’s Android 16 version.
What is HDR?
HDR, or high dynamic range, describes photos or videos that have a larger range of brightness and colour than standard dynamic range (SDR) content. The end result is more realistic graphics with brighter highlights, deeper shadows, and increased detail, making images appear more lifelike. Essentially, HDR seeks to record and display a wider range of light and dark tones, closer to what our eyes see in the actual world.
To display HDR content, devices require HDR screens with a broader colour gamut than the relatively limited sRGB standard. While some current Android phones and tablets have HDR displays, the majority of content remains in SDR.
Critically, even screenshots of HDR content captured with these devices are currently preserved as SDR. This is because Android does not preserve additional colour information when encoding screenshot images; the encoding procedure for the SDR screenshot format loses additional colour information from HDR material.
With the addition of end-to-end support for HDR video in Android 13, Google had to adjust Android’s screenshotting algorithm so that screenshots closely matched what was on screen. However, because screenshots remained in SDR format, HDR sections within them appeared dimmer, and SDR content appeared as brilliant as HDR content.
Android 14 added support for HDR pictures, often known as Ultra HDR, complicating matters even more. Because HDR photos are frequently displayed within SDR app UIs, Google needed to find a technique to encode both the SDR UI and the HDR image in a single SDR snapshot. Because screenshots remained in SDR, Google brightened the app’s interface and clipped HDR highlights. The end result is that screenshots don’t truly capture what you’re actually seeing.
What-is-HDR
Left: A screenshot of an HDR video superimposed on a Chrome website with Ultra HDR. Right: A snapshot of an HDR video placed on top of the Settings app, followed by other screenshots. Both screenshots were taken using Android 14. Source: Google.
HDR in Android screenshots.
In Android 15 QPR1, the operating system added a local tone-mapping algorithm for HDR screenshots. This technique keeps UI colours while also preventing HDR highlights from being clipped, making it significantly easier to take screenshots of HDR content. Even with the improvements, screenshots are still SDR and will not have the same impact on HDR TVs.
HDR-in-Android
Left: A screenshot of an HDR video superimposed on a Chrome website with Ultra HDR. Right: A snapshot of an HDR video placed on top of the Settings app, followed by other screenshots. Both screenshots were captured with Android 15 QPR1, which employs a tonemapper to preserve UI colours and HDR highlights. Source: Google.
Finally, Google is adding support for genuine HDR screenshots in Android 16. In Android 16 Beta 2, I discovered that screenshots of HDR content were stored in HDR format. When I opened these screenshots in the Photos app on my Pixel phone, I noticed my screen brighten and HDR highlights begin to pop. I verified this by comparing screenshots of the identical HDR image taken before and after updating my Pixel 7 Pro to Android 16 Beta 2. The pre-update screenshot was in SDR, and the post-update screenshot was in HDR.
Digging through Android’s source code, I discovered many references to a “true HDR screenshots” capability in SurfaceFlinger, a system function that is crucial for screen rendering on Android. When the “true HDR screenshots” functionality is turned on, HDR content can be screenshotted without tone mapping.
Display analyst Dylan Raga and GitHub user ledoge examined Android 16’s HDR screenshots and determined that they are PNG files with HDR gainmaps included in them. Most ordinary tools fail to detect these gainmaps, but a specialised PNG inspector does. These gainmaps enable screenshots to show as HDR on Android 16 devices but as SDR on other devices.
It’s unclear why Google used PNG for HDR screenshots rather than a format supported by Ultra HDR, such as JPEG. Perhaps they wanted to avoid any JPEG compression artefacts, especially when cropping. Hopefully, Google will publish more information about how HDR screenshots in Android 16 operate so that we can better understand how to transfer them between devices.
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