Sony ARWs record shading, lateral chromatic aberration and distortion as a camera setting plus a radial
table in the raw image IFD (0x7031-0x7037), with copies in the encrypted SR2SubIFD (0x797c-0x7982).
They are now decoded for every body that records them and carried through RawInfo and RawImage as
`lens_metadata.sony` (types in crates/raw/src/lens_metadata.rs, decoder in
crates/raw/src/vendor/arw_lens.rs):
- Raw-IFD fields are the ones the TIFF reader parsed, which is what the image itself uses. A scan of
the directory adds diagnostics only: repeated tags, and why an entry the reader skipped was dropped
(values outside the file, an unknown type, past the reader's limits). SR2SubIFD fields are read
from their first entry. Only the exact layouts are accepted: SHORT[1] or non-negative SSHORT[1]
settings, SSHORT[17] headed by 16 for shading and distortion, SSHORT[33] headed by 32 for CA.
Nothing is allocated from a count in the file.
- The raw IFD's copy wins. The SR2SubIFD copy fills in only for a tag the raw IFD lacks, never for a
malformed one, and the two copies' agreement is recorded.
- Settings keep their number and their documented meaning, Unknown(value) otherwise (never Off).
- Framing evidence (stored frame, Sony and default crops, reference rectangle, coding, 3:2) and a
per-component status. Only Applied components become opcodes.
Applied corrections are unchanged: the ILCE-7RM4A distortion conversion receives exactly the table it
received before, and no other body or component gains a correction. The ILCE-7CR distortion misses its
camera JPEG at 24 mm, and shading and CA semantics are not validated on any body; see
docs/sony-lens-corrections.md.
Locating the SR2SubIFD, now done for every ARW that has one, selects the SR2Private offset, length and
key with the TIFF reader's own rules, which lightcraft-tiff now exposes and builds its reader on
(directory_entries, entry_span, ParseOptions::budget_for, decode_value). Only each field's first value
is decoded, so the directory's other entries cost no memory sized by the file: a 16 MiB file whose
SR2Private holds eight fields aliasing it peaks at 37 kB. DirectoryEntries keeps its layout private,
and its positions() iterator uses checked arithmetic.
Tests: synthetic decoder tests; a differential test of the SR2Private selection against the TIFF
reader's in both byte orders (0 to 8,193 filler entries, unreadable and unusual first occurrences of
each field, a used-up value budget); a dhat peak-heap test; public-corpus checks against the values
ExifTool prints, with pinned and anchored SHA-256s (LIGHTCRAFT_CORPUS_REQUIRED=1 makes absent files
fail); and an opt-in local inventory check (crates/raw/tests/sony_lens_inventory.rs).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
libtest has no skipped status and hides the output of passing tests, so a
test that returns early without a GPU, a corpus file, a craft-fonts face or
a model passed silently. `lightcraft-testkit` (the testkit slot the layering
table already reserves, dev-dependency only, std only) adds
`skip!(Need, "reason")`: it prints the note as before and, when
LIGHTCRAFT_SKIP_LOG names a file, appends one JSON line (need, reason, test,
binary, file:line). Plain `cargo test` is unchanged. The 61 existing skip
sites use it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
DNG export gains a "Lossy" compression: the raw data is demosaiced to linear
camera RGB (OpcodeList3 and the default crop applied), scaled to the resize long
edge when one is set, and stored as 8-bit baseline JPEG tiles at the export
quality. The codes follow a 1/2.2 power curve that a LinearizationTable maps
back to linear 16-bit values; colour matrices, white balance and the profile
look are kept. Available in the export dialog, `app.export`
(`dngCompression: "lossy"`) and the MCP export tool.
Also fixes a new clippy lint (chunks_exact_to_as_chunks) in pipeline/spots.rs
that fails `cargo xtask ci` on Rust 1.99.
Sources: Adobe DNG Specification 1.4+ (Compression 34892, LinearizationTable);
own design for the code curve.
Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
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>
DNG compression 34892: each tile / strip is a baseline JPEG of 8-bit samples (decoded with
zune-jpeg, pure Rust), then the usual linearization table, levels and crop apply. Per the DNG
specification. Lossy DNGs (Smart Previews, "lossy compression" DNG exports, many phone DNGs)
now open as raw files instead of falling back to their embedded preview. Unit test with
synthetic JPEG tiles (edge tile cut short); the corpus sample decodes (5760×3840 in 144 ms).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Classic + BigTIFF, both byte orders, all field types, SubIFDs and Exif/GPS/
Interop pointer IFDs, strips/tiles layout, maker-note offset-base helpers,
IFD writer; hardened against malformed input (proptests). Placeholder
manifests for lightcraft-meta and lightcraft-raw.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Brandon Thomas