darktable-org / darktable-org/rawspeed

Support JPEG XL compression in DNG

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#516 15 comments 0 reactions 0 assignees View on GitHub

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Dominant language
C++
Stars
456
Forks
147
PR merge metrics
No merged PRs in 30d

Description

Just added in DNG 1.7, and is allowed for e.g. 3-channel LinearRaw photometric interpretation.

Available (C) implementations:

https://github.com/libjxl/libjxl (reference)
https://github.com/lifthrasiir/j40 (single header, public domain)

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start by reading the DNG 1.7 specification for JPEG XL compression and comparing the linked libjxl and j40 implementations. Then inspect rawspeed's existing DNG compression and decoder paths. Done means decoding JPEG XL-compressed DNG files, including the stated 3-channel LinearRaw case, with suitable coverage.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp
Domain
computer-vision
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Quiet
Clarity
Mostly clear
Newbie friendliness
45/100

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