Ultra HDR

Ultra HDR
DeveloperGoogle
Release4 October 2023; 3 years ago (2023-10-04)
Stable release
1.1 / October 25, 2024; 2 years ago (2024-10-25)
Websitedeveloper.android.com/media/platform/hdr-image-format

Ultra HDR is an image format that encodes a gain map into the metadata of a JPEG image. This allows for compatible decoders to decode and display a high dynamic range (HDR) image while maintaining backwards compatibility with incompatible decoders and standard dynamic range (SDR) panels. This format was first deployed on the Android 14 operating system, with display support later being added to Google Chrome, Microsoft Edge, Brave, Opera, Safari, and multiple other macOS and iOS applications.

Technical details

An SDR image (left) and the corresponding gain map (right) used to derive the HDR image on compatible displays

An Ultra HDR image file contains a 8-bit standard dynamic range (SDR) image together with a gain map encoded as a monochromatic JPEG image. XMP tags such as hdrgm:GainMapMin and hdrgm:GainMapMax are placed inside the gain map's JPEG container to indicate how the 8-bit pixel values (0–255) should be converted into base-2 log values, by which the corresponding pixels in the main image are multiplied to derive the HDR image. The gain map may be downsampled to 1/4 of the width and height of the primary image, or 1/16 the number of pixels, and must have a similar aspect ratio.

Ultra HDR uses an encoding scheme developed by Adobe. Samsung brands Ultra HDR as Super HDR. A similar standard for gain map based HDR with backwards compatible SDR support for any image file type, including JPEG, is ISO 21496-1. ISO 21496-1 is branded by Apple as Adaptive HDR. As of Android 15, the Ultra HDR and ISO 21496-1 over JPEG formats are encoded simultaneously for HDR compatibility across Android and Apple devices.

See also

References

  1. ↑ Benz, Greg (2023-09-26). ""Gain maps" make HDR look great on any screen - Greg Benz Photography". gregbenzphotography.com. Retrieved 2025-11-08.
  2. ↑ Benz, Greg (2025-06-12). "Apple Safari now supports HDR photography! - Greg Benz Photography". Retrieved 2025-11-08.
  3. ↑ "HDR photo editing with machine learning". Google Research. Google. Retrieved 2025-07-01.
  4. ↑ Rahman, Mishaal (2023-10-09). "Hands-on with Ultra HDR in Android 14: The future of photography". Android Police. Retrieved 2025-07-01.
  5. 1 2 "Ultra HDR Image Format v1.1 | Android media". Android Developers. Retrieved 2025-07-01.
  6. 1 2 3 Rahman, Mishaal (2024-10-29). "Google and Apple are making HDR photos work better on Android and iOS". Android Authority. Retrieved 2024-11-10.
  7. ↑ Romero, Andrew (2024-04-02). "Samsung's Super HDR is not coming to older Galaxy devices". 9to5Google. Retrieved 2024-11-11.
  8. ↑ Benz, Greg (2024-09-27). "What do Apple's latest updates mean for HDR photography?". Greg Benz Photography. Retrieved 2024-11-10.
  9. ↑ "Ultra HDR Image Format v1.1 | ISO 21496-1 Compatibility". Android Developers. 2024-10-25. Retrieved 2025-11-07.