darktable-org / darktable-org/darktable
Support HDR gain maps
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- Dominant language
- C
- Stars
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- Forks
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- Avg merge
- 22h 14m
- Merged PRs (30d)
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Description
The storage of SDR image + gain map is currently being standardized as ISO/CD 21496-1.
This is already used by Adobe in "enhanced" DNGs, in Google's UltraHDR JPEGs (see also libultrahdr), and by Apple in HDR iPhone HEICs.
libavif and libjxl also added preliminary support for it.
Ideally, both import and export should be supported.
This approach seems to be gathering more momentum in the market compared to e.g. "true" 10-bit HDR only containers.
Related:
https://gregbenzphotography.com/hdr-photos/jpg-hdr-gain-maps-in-adobe-camera-raw/
https://www.reddit.com/r/DarkTable/comments/1f421d0/how_to_export_an_hdr_image_taken_on_iphone/
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reading the ISO/CD 21496-1 reference and the linked Adobe, Google UltraHDR, libultrahdr, libavif, and libjxl material to understand the gain-map format. Determine how darktable would import and export SDR images with gain maps; done means both directions support the standardized representation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- computer-graphics, desktop
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100