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>
The D1X/D1H raw SubIFD is 4028x1324 with XResolution 600 / YResolution 300:
the pixel is twice as tall as it is wide. Nothing read that, so the
picture came out about 3:1. Add a pixel aspect to RawImage/RawInfo, read
it from the raw IFD resolution ratio (NEF) and from DefaultScale (DNG),
accept only 1.5..4, and resample the rows after demosaic. developed_size()
reports the stretched size, binning is off for non-square pixels, and the
catalog and lens-profile sizing use developed_size().
Main's reconstruction (#607) replaces this branch's rewrite of highlight::reconstruct. Kept from the
branch: develop_binned_masked (clipping decided per sample before averaging) and the denoised twin
using the same mask. New: highlight::reconstruct_masked, #607's reconstruction with the clipped
channels told by the mask (block means as lower bounds), shared with reconstruct_with through a
generic clip test (no slowdown on full-size images), and CameraColourModel::rebuild_highlights_masked
so binned previews keep the colour model's clipped white. RENDER_CACHE_VERSION 38.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Highlight reconstruction rebuilds clipped channels from the chromaticity of
unclipped pixels nearby. Three changes to that colour:
- an unclipped pixel counts by its brightness ((m / 0.8 clip)^4, at most 1),
filled coarse to fine by push-pull, so dark wires across a bright cloud no
longer tint it (the iPhone frame of #548 turned cyan at Highlights -100);
- pixels within 6 px of clipping (partly demosaiced from clipped samples, 25 %
greener than the sky on that frame) give no colour unless nothing else does;
- the rebuilt colour is drawn toward neutral at its brightest channel as more
channels clip ((n - 1 + s) / 2, s rising as the next channel nears its clip).
Binned previews keep each channel the mean of its block and mark blocks with a
clipped sample in a mask (develop_binned_masked, reconstruct_masked), instead
of taking the block maximum: one clipped specular sample no longer becomes a
green speckle at 500 px (HUAWEI PRA-LX1, WAS-LX1A). The denoised twin uses the
same mask. Camera-colour fitting keeps the old binning.
RENDER_CACHE_VERSION 26 (adjust at merge).
- lightcraft-raw: RawImage::develop_binned(k) — k×k superpixel binning of the CFA
(Bayer k even, X-Trans k multiple of 3), black/white normalised row by row, default
crop only, clipping preserved for highlight reconstruction. 2560 px previews of a
24 MP raw bin 2×, thumbnails 4–8×; exports / 1:1 still demosaic (AHD) at full size.
- highlight::reconstruct and its pyramid fill are rayon-parallel (bit-exact).
- X-Trans directional demosaic: precomputed per-phase neighbour offsets and no
reflection in the interior, no per-pixel allocation (bit-exact, tested against the
reference formulation): 2.9 s → 0.75 s CPU at 24 MP.
- files::load_bytes runs on a rayon worker so its short parallel loops don't each
wait for the pool to wake (dominant cost on a loaded machine); LIGHTCRAFT_PROFILE
prints per-stage source timings; files::bin_factor picks the block size.
- render_bench ONLY=source: per-file decode / normalise / demosaic / binning / load.
- Fix: u64 overflow on hostile IFD sizes in DNG/ARW/NEF raw-IFD selection (proptest).
load_bytes(2560) CPU time, ARW a7 III 24 MP: 2347 → 240 ms; X-T20: 3120 → 1220 ms.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Brandon Thomas