file-format-parity.md

File format parity

Last reviewed: 2026-10-10 · Last updated: 2026-10-12 · Change: minor (Render to DNG as an export format) · Target: Adobe Lightroom Classic 15.5 / Lightroom 9.6

Every format Lightroom reads or writes, with our support, fidelity and tests. Camera raw formats are deep enough to have their own document: raw-parity.md.

How measured: the target's document types come from the installed Lightroom 9.6 Info.plist (CFBundleDocumentTypes: catalog mcat, xmp, toolkit / module / library bundles, and the raw-and-image list: jpg, tif, dng, heic and 27 raw extensions) plus Lightroom Classic's documented import and export formats. Ours come from crates/codecs/src/sniff.rs, crates/codecs/src/encode.rs, crates/engine/src/export.rs, crates/engine/src/import.rs and the tests named below.

Images (non-raw)

Format	Target reads	Target writes	LightCraft reads	LightCraft writes	Notes / tests
JPEG	✅	✅	✅ (parallel decoder, ICC, EXIF orientation)	✅ quality, size limit, ICC, metadata	crates/codecs/src/jpeg.rs, export tests
TIFF	✅ 8/16/32-bit	✅ 8/16-bit, LZW/ZIP	✅ 1–64-bit integer, 16–64-bit float, bilevel, CCITT fax, WhiteIsZero	✅ 8/16-bit, 32-bit float linear, none / LZW / ZIP	crates/tiff, crates/codecs/src/tiff_codec.rs
PNG	✅	✅	✅	✅
PSD / PSB	✅ (maximized-compatibility composite)	✅ (Classic: PSD export, edit-in round trip)	✅ merged composite	⬜ (external-editor round trip writes 16-bit TIFF)	crates/codecs/src/psd.rs
HEIC / HEIF	✅	⬜ (Classic) / HDR only	✅ in every release build (crates/heif, heic-rs)	⬜	heif feature on by packaging scripts
AVIF	✅	✅ (HDR)	⬜ recognised, not decoded (no permissive pure-Rust AV1 decoder)	✅ 8/10-bit, PQ HDR
JPEG XL	✅	✅	✅ (jxl-oxide) incl. DNG 1.7 JXL tiles	✅ lossy / lossless, 8/16-bit, PQ HDR (jixel, native only; ⬜ web)	crates/engine/src/tests_export.rs
WebP	not in its document types	⬜	✅	✅	beyond target
GIF, BMP	⬜	⬜	✅	⬜	beyond target
DNG (from raw)	✅	✅ incl. lossy, embedded original	✅	✅ uncompressed or LJ92; ⬜ lossy DNG, embedded original	crates/raw/src/dngwrite.rs
Render to DNG (15.5)	—	✅	—	🟡 export format "Rendered DNG" (linear float DNG, edit baked in); not yet added to the catalog	crates/raw/src/dngwrite.rs (write_rendered_dng)
Original + sidecar	—	✅	—	✅
HDR gain map JPEG (ISO 21496-1)	✅	✅	✅ (gain map read)	✅	crates/codecs/src/gainmap.rs
PQ / HLG HDR	✅	✅ AVIF, JXL, TIFF	—	🟡 PQ AVIF, PQ JPEG XL, float TIFF; no HLG
Contact sheet / print PDF	—	✅ (Print module: PDF / JPEG / printer)	—	🟡 paginated contact-sheet PDF (A4 / Letter, 150 dpi, sRGB)	crates/engine/src/contact_sheet.rs
Video (MP4, MOV, AVCHD…)	✅ playback, trim, edit	✅ export	🟡 catalogued (kind, duration)	⬜	see video gap

Colour spaces and profiles

Feature	Target	LightCraft
Export colour spaces	sRGB, Adobe RGB, Display P3, ProPhoto, Rec.2020, custom ICC	✅ sRGB, Display P3, Adobe RGB-compatible, ProPhoto, Rec.2020 with gamut mapping (CPU and GPU), embedded ICC; ⬜ custom ICC output profiles; AVIF stays sRGB
Input ICC (JPEG / TIFF / PNG)	✅	✅ matrix / TRC and LUT profiles (moxcms)
Soft proofing with printer profiles	✅	🟡

Metadata, sidecars, presets and catalogs

Format	Target	LightCraft	Notes
XMP sidecars (crs: develop settings, ratings, keywords, regions)	read / write	✅ read / write, manual (⌘S) and automatic	xmp-interop.md
EXIF / IPTC / XMP embedded on export	✅	✅ with metadata filters	crates/meta
Develop presets .xmp	✅	✅ import (mapping of supported settings)
Legacy presets .lrtemplate	✅ (converted)	✅ import
Camera / creative profiles (.dcp, .xmp profiles)	✅	⬜ deliberately (Adobe profile formats are never used); .cube LUT profiles ✅
Lens profiles .lcp	✅	⬜ deliberately
Other apps' presets	—	✅ Luminar .lmp / .mplumpack, .zip bundles	beyond target
Lightroom Classic catalog .lrcat	native	🟡 import (ratings, flags, labels, keywords, collections, virtual copies, supported develop settings; read-only pure-Rust SQLite incl. WAL)	lightroom-catalog-import.md
Lightroom (cloud) library .lrlibrary	native	⬜	cloud library format, local cache only
Write back to .lrcat	native	⬜ (one-way migration by design)
Keyword lists (text)	import / export	✅
GPX track logs	✅	✅	crates/meta/src/gpx.rs
Export presets, metadata presets, filename templates	✅ (.lrtemplate)	✅ own JSON	not interchangeable
Lightroom plug-ins (.lrplugin, .lrdevplugin)	✅	⬜	see ecosystem in target-app-parity.md

Scores

Part	Weight	Ready for real work	Kind
Standard image import / export	35%	~85%	estimated (table above; missing: AVIF read, PSD write, lossy DNG)
Sidecars, metadata, presets	25%	~85%	estimated
Lightroom catalog migration	25%	~50%	estimated (one-way, approximate rendering of unsupported settings)
HDR, print, video output	15%	~35%	estimated
Non-raw file formats	100%	~70%	estimated; raw is in raw-parity.md (~50%)

Remaining: 26–47 h (AVIF decode 8–15 h if a permissive decoder is written or found; PSD write 4–8 h; lossy DNG and Render to DNG 4–8 h; HLG 3–5 h; catalog import depth 8–12 h).

Revision history

Date	Change	Summary
2026-10-10	major	Created from the code and the installed Lightroom's document types
2026-10-10	minor	JPEG XL export (#247): JXL write ✅ (native only), PQ JPEG XL HDR
2026-10-12	minor	Render to DNG: "Rendered DNG" export format (linear 16-bit float DNG of the rendered photo)