RAW Read Parity Plan

This page tracks the public read-path work needed to move OpenMeta closer to ExifTool-level camera RAW coverage. It is about decoding and interpretation, not writer policy.

OpenMeta should keep a conservative rule here: preserve raw payloads whenever a family is only partially understood, and only promote fields to structured entries when their location, type, byte order, and meaning are stable enough to test.

Validation Method

RAW parity work is compared against ExifTool output with normalized values, group names, and intentional-difference notes. Each new lane should add:

• a block-discovery test for the native container or embedded metadata carrier

• a structured decode test for stable tags

• a display-name or semantic-group test when the tag is user-visible

• a transfer-safety test when the decoded value is source-specific

• a compare note for unsupported or intentionally raw-only payloads

Family Gap Matrix

Family	Current lane	Main gap versus ExifTool	Next work
DNG and TIFF-based RAW	Strong baseline through TIFF/EXIF/IFD, DNG tags, XMP, ICC, and MakerNote payloads	Long-tail vendor private tables and model-specific MakerNote fields	Keep adding named tables only when they are stable and safety-classified
Nikon NEF/NRW	Strong TIFF/EXIF path plus expanded Nikon MakerNote tables and normalized Nikon Capture crop bounds	Model-specific encrypted/custom-setting tables and less common correction records	Add focused Nikon tables with byte-order/version gates and safety buckets
Sony ARW/SR2/SRF	Strong TIFF/EXIF path plus Sony RAW/source-processing classification and panorama crop-margin interpretation	Older SRF/SR2 private structures and model-specific private tables	Extend native SR2/SRF table naming and keep raw payload preservation as the fallback
Canon CR2	Strong TIFF/EXIF path plus Canon MakerNote, normalized aspect/crop geometry, and crop/aspect/color-data classification	Long-tail Canon custom functions and per-model color/correction tables	Continue table-by-table decode with rendered-transfer safety coverage
Canon CR3	Bounded BMFF plus EXIF/XMP/ICC/CR3 maker metadata	Deeper BMFF item/property graph semantics and CR3-specific private records	Deepen BMFF metadata graph interpretation before broad CR3 private-table work
Canon CRW/CIFF	Partial native lane: recursive CIFF directories, stable scalar/subtable decoding, common native names, and derived EXIF bridge	Older Canon private tables and long-tail legacy records	Continue table-by-table decode only where stable validation data exists
Fujifilm RAF	Partial native lane: header-declared preview-JPEG EXIF/XMP discovery, FujiIFD/TIFF follow path, RAF header fields, RAF directory geometry tags, RAFData geometry projection, normalized raw crop/zoom rectangles, and standalone XMP fallback	Model-specific RAF tables and less common native sections outside the stable carrier/header/directory subset	Extend native RAF section inventory table-by-table, with broader color/correction safety buckets before transfer use
Sigma X3F	Partial native lane: header fields, known PROP properties, section-directory JPEG metadata follow path, and legacy embedded-EXIF fallback	Deeper image-processing/compression sections and model-specific private records	Add X3F native sections only when they expose stable user-visible fields or transfer-safety inputs
Panasonic, Olympus, Pentax, Kodak, Minolta, Samsung, Ricoh	Mixed TIFF/EXIF and MakerNote table coverage	Older model tables, preview/correction subtables, and private RAW payloads	Prioritize tables that affect crop, color, lens correction, orientation, or transfer safety
Apple, DJI, Google, FLIR	Live-vendor source-processing classification exists for rendered-transfer safety	Computational, thermal, radiometric, and shot-log interpretation depth	Add decode only for stable fields that hosts can use safely
Rare and legacy RAW families	Raw-preservation-first	Native container and MakerNote depth	Preserve raw blocks, then add support only when validation inputs and stable structure are available

Priority

1. Keep writer safety explicit: decoded MakerNote sub-IFDs are not used to reconstruct vendor MakerNote blobs; the original raw MakerNote payload is preserved when available.

2. Continue high-visibility native read gaps: more model-specific RAF native sections, long-tail CRW/CIFF private tables, and deeper X3F section interpretation.

3. Deepen BMFF interpretation for CR3, HEIF, and AVIF metadata graphs.

4. Add X3F image-processing section decode only when the fields can be named, typed, and safety-classified.

5. Continue vendor MakerNote table work for fields that affect crop, color, orientation, lens correction, or safe transfer decisions.