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CinemaDNG (camera RAW) import: clean-room DNG decoder #1065
Description
Camera RAW support is at 0% (docs/codec-parity.md). CinemaDNG is the one widely used cinema RAW format with a public specification, so it can be implemented clean-room in pure Rust without any vendor SDK. Related: #383.
Spec basis (public documents only)
- Adobe Digital Negative (DNG) Specification, versions 1.4 – 1.7 (public PDF)
- TIFF Revision 6.0 and TIFF/EP (ISO 12234-2)
- ITU-T T.81 / ISO/IEC 10918-1, lossless JPEG (process 14, "LJ92")
- CinemaDNG format description (DNG image sequences in folders, or MXF-wrapped)
No other decoder's source (dcraw, LibRaw, rawspeed, darktable, RawTherapee, ffmpeg, the Adobe DNG SDK…) is read.
Scope of the first PR
- DNG/TIFF container: IFD parsing incl. SubIFDs, bounded and hostile-input safe (offset/size checks, IFD cycle/count limits, capped allocations).
- Raw CFA data: uncompressed (8–16-bit, packed and unpacked) and lossless JPEG (T.81 process 14, predictors 1–7, tiles and strips).
- Processing to RGB following the DNG pipeline: linearization table, black/white levels (incl. per-CFA black), DefaultCrop, AsShotNeutral white balance, demosaic, ColorMatrix/ForwardMatrix to a linear working space, and an output transform consistent with FilmCraft's colour pipeline.
- CinemaDNG sequences: a folder of numbered
.dngframes imported as one clip (reusing image-sequence import), frame rate from the CinemaDNG FrameRate tag when present. - Tests on synthetic DNGs written by a test-only spec-based writer (no camera files committed), plus hostile-input tests.
Out of scope for the first PR: lossy DNG (JPEG/JPEG XL), MXF-wrapped CinemaDNG, opcode lists, a Raw/Color settings UI.
I'm working on this and will open a PR.
Activity
vangel76 commentedon Oct 11, 2026
Follow-up work on the decoder internals (building on #1068), which I'm doing now in a separate PR:
ProcessOptions(raw development settings: white balance as shot or temperature/tint, exposure, highlights, demosaic quality, output space, target size for a reduced-resolution path), lossy JPEG DNG (Compression 34892), DNG opcode lists (OpcodeList1/2/3, DNG 1.7 chapter 7), and faster CinemaDNG decode/processing. JPEG XL DNG (52546) may follow as a separate draft PR behind an off-by-default feature, since it needs a new dependency (maintainer decision).storytold#1065: optional serde derives on the DNG raw settings
storytold#1065: faster DNG decode and development, reduced-resolution…
storytold#1065: tint sign of the DNG white balance follows the raw-co…
storytold#1065: DNG opcode lists (OpcodeList1/2/3)
storytold#1065: lossy JPEG DNG (Compression 34892)
storytold#1065: DNG README: CinemaDNG spec edition, MXF-wrapped Cinem…
storytold#1065: JPEG XL DNG behind an off-by-default `jxl` feature
vangel76 commentedon Oct 11, 2026
Merge order for the CinemaDNG series (each builds on the previous one, so each PR also shows the earlier commits until those land):
ProcessOptions(raw development settings), faster decode/develop incl. reduced-resolution development, DNG opcode lists, lossy (JPEG) DNGjxlcargo feature; adds a new dependency, so it needs your decisionAfter each merge I'll merge
maininto the next branch and push, so nothing needs resolving on your side. #1068 also overlaps #837 (OpenEXR) insequence.rs/still.rs; same applies there.#1065: clean-room DNG / CinemaDNG decoder crate
#1065: import DNG stills and CinemaDNG folders as one clip
Merge pull request #1068 from vangel76/feat-cinemadng
storytold#1065: DNG opcode lists are opt-in (ProcessOptions::apply_op…