Compression 52546 tiles and strips decode through jxl-oxide (new
default-on `jxl` feature of lightcraft-raw): bare codestreams and
ISO-BMFF containers, 1 or 3 planes, 8-16-bit integers scaled back
exactly from the codestream's own bit depth, 16-bit floats. Edge tiles
may be coded at their nominal or in-image size. Headers are checked
against the IFD in header-only probing too. A single-chunk JPEG XL
preview IFD (RGB or grey) is offered as the embedded preview.
The decoder's memory is bounded by the tile: 16 bytes per sample (three
times that for a lossy grey tile, which the decoder expands to three
channels) plus 64 KiB; jxl-oxide 0.12 was measured at <= 10.3 bytes per
sample for lossless and <= 13.5 per colour sample for lossy tiles. A
codestream needing more (e.g. extra channels) is an error.
Lossless tiles are checked bit-exact on synthetic CFA and LinearRaw
files (zune-jpegxl as a test-only encoder); lossy tiles are unverified
on a real file.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
scan_for_jpeg walks every JPEG-like start in a container it can't parse;
each walk runs through the marker segments that follow (up to 4096) and
their entropy data. A crafted CRW/MRW/X3F (or unsupported TIFF raw) of
fake starts one after another makes every walk cover most of the file:
quadratic, about a minute for 40 MB, on the import's probe thread. The
walks now report how far they read and share a budget of eight times the
file's size (at least 1 MiB); real files' candidates fail within a few
bytes or are the preview itself. Test: 200,000 fake starts, 0.15 s.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01912WaK6Rmew3wxZuPyX7E8
Widens the preview-only fallback. A recognised raw whose decode fails now falls back
to its embedded JPEG for any decode error (unsupported, corrupt, limit, TIFF
structure), not only an unsupported variant, and the preview search covers more
containers:
- Canon CRW, Minolta MRW and Sigma X3F are recognised by their magic (RawFormat
Crw, Mrw, X3f) instead of failing as "RawOther files are not supported yet".
- A TIFF whose IFD0 has no ImageWidth/ImageLength but a JPEG pointer or SubIFDs
(Kodak KDC) is a raw container, not a malformed image. TIFF compression 99
(Leaf MOS) counts as a raw compression.
- When no tag points to a preview, a recognised raw we cannot decode is scanned
for the largest complete three-component DCT JPEG. A preview whose first byte
was overwritten (Minolta, Epson) is restored. A one-component JPEG is skipped
(a PowerShot CRW stores its mosaic that way).
Files with no JPEG at all still fail with "without an embedded preview".
CR3 files imported as preview-only with the 1620x1080 PRVW JPEG and no metadata
(no camera, capture time, exposure, lens or GPS): nothing read the container.
- crates/meta/src/cr3.rs: bounded ISO base media box parser for CR3 (Canon uuid
box with CMT1-4 and THMB, tracks with their sample entries, CMP1 coding header
and sample location, XMP uuid box). Every size/offset checked; depth and box
count bounded.
- Metadata: CMT1 (IFD0), CMT2 (Exif) and CMT4 (GPS) merged into one TIFF Exif
block, so CR3 reads like any TIFF-based raw; XMP from its uuid box.
- Preview: the full-size JPEG track (6960x4640 on an EOS R6 Mark III) before
PRVW/THMB; imports report the full image size.
- Tests: synthetic CR3 (boxes, tracks, merged Exif), truncation/corruption sweep,
JPEG track preferred over PRVW with fallback.
Raw (CRX) data is still not decoded; CR3 stays preview-only.
- embedded_preview: CR3 PRVW/THMB boxes (plus RAF, RW2, ORF, PEF from the
format commits); stops at the first valid box of each kind
- engine: raw variants that report Unsupported are probed and shown from
their embedded JPEG (orientation from the JPEG or the raw), not an error
- crates/raw/tests/corpus.rs: every corpus/raw file is recognised, has a
JPEG preview (DNG optional) and decodes or is a known-unsupported
variant; prints decode timings
- xtask corpus --download: 37 CC0 raw.pixls.us samples (matched by SHA-256)
- ROADMAP/crate docs: format coverage, NEF Huffman / RW2 format 4 /
compressed ORF+RAF gaps, neutral colour-matrix fallback
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
16-bit LE words (12-bit-in-top-bits detected and shifted), 12-bit rows
of LE 32-bit words read MSB-first (black-box), maker-note
ImageProcessing crop, BlackLevel2, WB_RBLevels for old- and new-style
notes, CFA phase from the data (GRBG/RGGB), CameraSettings preview.
Compressed ORF reports Unsupported (documented gap).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Black-box derived layout: 0x4000-byte chunks stored rotated by 0x1ff8,
16-byte LE blocks read LSB-first (10x12-bit or 9x14-bit samples).
Sensor borders, CFA code, per-channel black, linearity limit, WB levels,
ISO; JpgFromRaw preview via a generic undefined-tag JPEG candidate.
The quantised raw format 4 reports Unsupported (documented gap).
Adds a rawdump debug example.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
RAF header/record parsing, raw IFD (0xf000) with 16-bit, 12-bit LSB and
32-bit-word MSB packings found by black-box analysis of CC0 samples,
X-Trans layout (reversed record, anchored at 0,0), crop, black levels,
WB_GRB levels, metadata and preview from the embedded JPEG. Compressed
RAF reports Unsupported. Colour uses the documented neutral fallback.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
