Google Ultra HDR support

[Azzzaza]

Is it possible to support the new Google Ultra HDR format? Here's the official library: https://github.com/google/libultrahdr. The format looks pretty interesting as it allows combining SDR + HDR versions of the same image in 1 JPG file.

And sorry if this is not a proper place to ask a question, but what format do I need to use to be able to preview my HDR images? I tried all the HDR output formats supported by Adobe Lightroom, but none of them was displayed correctly in XnView MP, some images were almost completely dark, and some had washed out colors. The same images when saved in JPG/JPEG XL/AVIF and then imported into Apple Photos were rendered correctly.

[Kadet]

In version 1.6.2 JXL HDR is now correctly (pre)view.

[Azzzaza]

Even in 1.6.2 I still get very dark images. The colors seem to be correct, but the brightness is not. When I open the same file in Lightroom CC I can clearly see the sky maxing out the display brightness, while the app UI remains dim. With XnViewMP the whole screen is evenly lit making the image way too dark.

[Kadet]

Do You switch On ICC profile in settings?

[Azzzaza]

Yes, the ICC is on, with RGB and CMYK defaulting to the system profile when none is embedded, rendering intent perceptual and black point compensation unchecked. Tweaking any setting there has no effect.