feat/raw-thumb-embedded-preview #59

cameron · 2026-04-28T17:20:59Z

cameron commented

2026-04-28 17:20:59 +00:00

Fixes RAW thumbnail generation using exiftool

Fixes RAW thumbnail generation using `exiftool`

cameron added 2 commits 2026-04-28 17:21:00 +00:00

RAW: try IFD0 + IFD1 for embedded preview, serve at full size 00b3c80141

The thumbnail pipeline's embedded-JPEG extractor only checked IFD1
(THUMBNAIL), which on many Nikon NEFs is missing or zero-length even
when IFD0 (PRIMARY) carries a perfectly good 1-2 MP reduced-resolution
preview the camera writes for in-body review. The previous behavior
produced black thumbs on disk: the buggy IFD1 pointer resolved to a
short byte sequence that happened to satisfy the SOI sanity check,
image::load_from_memory accepted it, and the resize path quietly wrote
a black JPEG.

Now both IFDs are checked and the larger valid JPEG wins. Format-
agnostic: applies to every TIFF-based RAW (NEF / ARW / CR2 / DNG / RAF /
ORF / RW2 / PEF / SRW / TIFF). is_tiff_raw is now pub so main.rs can
gate its full-size handler on it.

Also extends the /image handler so size=full requests for RAW formats
serve the embedded preview as image/jpeg instead of NamedFile-streaming
the original RAW bytes - browsers can't decode a .nef container, so
<img src=...> would otherwise land as a broken image. Falls through to
NamedFile if no preview is present, preserving the historical behavior
for callers that genuinely want the original bytes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

RAW preview: exiftool fallback for MakerNote / SubIFD previews 6521a328bf

kamadak-exif's In::PRIMARY / In::THUMBNAIL only address IFD0 and IFD1.
On modern Nikon NEFs the full-res review JPEG lives in the MakerNote's
PreviewIFD (and many Canon CR2s / DNGs put theirs in a SubIFD chain) —
both unreachable through the existing reader, so the previous patch
still produced no preview for those files and the pipeline fell through
to ffmpeg, which writes black frames when it can't decode the RAW.

Add a slow-path layer in extract_embedded_jpeg_preview that shells out
to exiftool for PreviewImage / JpgFromRaw / OtherImage (one process per
tag). All candidates from both layers are pooled and the largest valid
JPEG wins. exiftool not on PATH degrades to fast-path-only behavior
rather than breaking — the fallback is a strict superset.

Documented the new optional dependency in README.md and CLAUDE.md with
install commands for apt / brew / winget / choco.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

cameron merged commit 9d58547ce3 into master

2026-04-28 17:21:29 +00:00

cameron deleted branch feat/raw-thumb-embedded-preview

2026-04-28 17:21:29 +00:00

cameron referenced this issue from a commit

2026-04-28 17:21:30 +00:00

Merge pull request 'feat/raw-thumb-embedded-preview' (#59) from feat/raw-thumb-embedded-preview into master

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Reference: Apps/ImageApi#59