API Stability

This page defines the adoption status for public OpenMeta APIs. Python bindings mirror these labels unless a Python wrapper documents a different status.

OpenMeta 0.8.3 retains the unfrozen development ABI label 4. C++ layouts and APIs may change without advancing this label; consumers rebuild against matching release headers and libraries. CMake package discovery permits a newer release within the requested major version; this does not guarantee ABI compatibility. Existing patch/handoff and snapshot v1 contracts retain their versioned guarantees. See Migrating to OpenMeta 0.8.

Stability levels

Level	Meaning
Stable	Intended for downstream use. Breaking changes require a new contract version, a compatibility path, or a documented migration.
Experimental	Public and tested, but the exact shape or semantics may still evolve while the surrounding workflow is being hardened.
Internal	Publicly visible only because it is part of a lower-level implementation surface. Do not build new downstream integrations on it unless another doc names it as supported.

Host-facing API map

API surface	Header	Stability	Notes
Host Adoption Profile v1: host_adoption_profile(), host_adoption_profile_matches(...)	openmeta/host_adoption.h	Stable	Exact compile-time/runtime contract descriptor for the narrow positional read, persistence, reconciliation, diagnostics, and typed codec-operation schema. See Host Adoption Profile.
Prepared Transfer Handoff v1: immutable template preparation/replay plus PreparedTransferHandoffInstance creation, exact-width/slot-count field queries, strict fixed-width patches, indexed views, replay, and runtime contract queries	openmeta/prepared_transfer_handoff.h	Stable v1	Move-only opaque owners hide routes and bundle state. Template preparation and worker creation may allocate. Instance query, patch, access, and replay allocate nothing; patch batches are exact-width, required-slot, alias-rejecting, and transactional. Independent instances own their payloads and may run concurrently. See Prepared Transfer Handoff.
Runtime capability query: metadata_capability(...)	openmeta/metadata_capabilities.h	Stable	v1 query contract for read, structured decode, transfer preparation, target edit, and raw-preservation status by format/family.
Positional source, snapshot, and read diagnostics: RandomAccessSource, source ranges/read windows, random_access_read_exact(...), read_transfer_source_snapshot_random_access(...), and collect_read_transfer_source_diagnostics(...)	openmeta/random_access_source.h, openmeta/metadata_transfer.h	Stable v1	Allocation-free exact callback reads, caller-owned accounting/scratch, owned finalized snapshots, explicit completeness/residual semantics, and caller-buffered structured diagnostics. Format coverage may grow additively. See Host Adoption Profile and Random-Access Input.
Low-level positional format decode, payload, and scan APIs: decode_exif_tiff_random_access(...), decode_exr_header_random_access(...), extract_payload_random_access(...), and the scan_*_random_access(...) family	openmeta/exif_tiff_decode.h, openmeta/exr_decode.h, openmeta/container_payload.h, openmeta/container_scan.h	Experimental	Format-specific structures and scratch requirements may still evolve. The stable top-level snapshot result exposes unsupported or incomplete lanes as explicit residuals.
Compatibility dumps: dump_metadata_compatibility(...), dump_transfer_compatibility(...)	openmeta/compatibility_dump.h	Stable	Stable v1 line-oriented compatibility dump contract, including generic BMFF component membership, role, relation-summary, policy, derived-image construction, and tiled-image configuration fields as normal bmff_field entries. See Compatibility Dump Contract.
XMP sync and writeback policy enums: XmpConflictPolicy, existing-carrier precedence enums, XmpWritebackMode, destination carrier modes	openmeta/xmp_dump.h, openmeta/metadata_transfer.h	Stable	Stable bounded writer policy for generated portable XMP. See XMP Sync And Writeback Policy.
Generic metadata traversal: visit_metadata(...), MetadataSink, ExportOptions, ExportItem	openmeta/interop_export.h	Stable	v1 traversal contract. Borrowed names are valid only during MetadataSink::on_item(...).
ExportNameStyle::Canonical and ExportNameStyle::XmpPortable	openmeta/interop_export.h	Stable	Stable naming modes for key-space-aware and portable exports.
ExportNameStyle::FlatHost	openmeta/interop_export.h	Stable	Stable v1 flat host naming contract. See FlatHost Mapping Contract.
Typed FlatHost import: import_flat_host_metadata(...)	openmeta/interop_import.h	Stable v1	Transactional detached-store reconciliation by exact source identity, unique FlatHost name, or explicit typed key. Removals retain stable Dirty | Deleted tombstones; ambiguous names are rejected.
Fresh metadata creation: create_metadata(...) and typed field helpers	openmeta/metadata_creation.h	Experimental	Transactional v1 contract for bounded host-provided logical fields. Produces a finalized canonical portable-XMP MetaStore, preserves additive creator/keyword order, rejects duplicate singletons, validates UTF-8/XML text and typed numeric constraints, and exposes the same C++ policy through thin Python bindings. Direct EXIF/IPTC projection remains a Translation concern. See Metadata Creation.
Generic typed metadata authoring: create_metadata_store(...), borrowed key/value helpers, and MetaStore::reserve(...)	openmeta/metadata_authoring.h, openmeta/meta_key.h, openmeta/meta_value.h, openmeta/meta_store.h	Experimental v1	Transactional bounded construction of finalized EXIF/TIFF/DNG-style, XMP, and IPTC-IIM entries. Unknown/private EXIF and custom XMP namespaces remain authorable; safe scalar/indexed custom XMP is supported. C++ only in this milestone. See Generic Typed Metadata Authoring.
Detached store/schema validation: validate_entry(...) and validate_store(...)	openmeta/validate.h	Experimental v1	Structured structural and initial TIFF/EXIF/GPS/DNG/XMP schema diagnostics with resource limits, duplicate-singleton checks, and optional image/CFA/color context.
Canonical TIFF/EXIF serialization: serialize_exif_tiff(...)	openmeta/exif_tiff_serialize.h	Experimental v1	Deterministic measure/write for unwrapped little-endian TIFF bytes. The same payload feeds existing target wrappers. Opaque MakerNotes drop by default. See Canonical Metadata Serialization.
Prepared TIFF/EXIF and scalar XMP patching: prepare_metadata_patch_plan(...), immutable plans, worker instances, and transactional typed patches	openmeta/metadata_patch.h	Experimental v1	Target-neutral opaque handles for typed EXIF and emitted scalar XMP values. Preparation and worker creation may allocate; mixed batches, payload access and library replay do not. Failure changes neither payload. See Prepared metadata patching.
Logical metadata editing: edit_metadata(...) and add/set/remove helpers	openmeta/metadata_editing.h	Experimental	Transactional v1 contract over finalized stores and the Creation logical field map. Set/remove preserve provenance through dirty values and tombstones; add handles deterministic repeated fields and explicit singleton conflicts. Python returns a detached edited Document without mutating its source. See Metadata Editing.
Reverse creation-date translation: translate_xmp_creation_dates(...)	openmeta/metadata_translation.h	Experimental	Transactional v2 projection of eligible edited XMP creation dates into exact native EXIF/IPTC date groups. The caller selects mappings, source mode, conflict behavior, and lowered resource limits; lossy precision, malformed dates, duplicate sources, and unresolved conflicts fail without replacing the output. Python exposes the same C++ transaction through a detached Document. See Metadata Translation.
Reverse technical EXIF translation: translate_xmp_technical_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v2 projection of exact xmp:ModifyDate, tiff:Make, tiff:Model, and xmp:CreatorTool properties into native EXIF groups. Full ModifyDate precision uses OffsetTime/SubSecTime companions; singleton conflicts, dirty tombstones, ASCII validity, duplicates, and resource limits are explicit. Python remains a thin detached-document wrapper. See Metadata Translation.
Reverse capture EXIF translation: translate_xmp_capture_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v2 projection of exposure time, F-number, ISO, focal length, and exposure compensation XMP properties into tag-specific native RATIONAL, SHORT, and SRATIONAL scalars. Exact integer conversion, portable/standard alias ambiguity, dirty tombstones, conflicts, and resource limits are explicit; unrepresentable decimals fail instead of being approximated. Python remains a thin detached-document wrapper. See Metadata Translation.
EXIF 3.1 LearningOptOutIn translation: translate_xmp_learning_opt_out_in_metadata(...)	openmeta/metadata_translation.h	Experimental v1	Bounded transactional projection of the exact exifEX usage/intention structure into native tag 0x9287. First usage, duplicate usage, complete shape, explicit 0300/0310 version policy, byte-order provenance, conflicts, tombstones and limits are explicit. Python mirrors the detached-store transaction. See Metadata Translation.
Profile authoring translation: translate_xmp_profile_metadata(...)	openmeta/metadata_translation.h	Experimental v1	Bounded transactional projection of TIFF ImageDescription, Artist and scalar Copyright plus EXIF ColorSpace and printable 8.3 RelatedSoundFile into native EXIF. Text encoding, legacy two-part Copyright conflict behavior, filename validation and limits are explicit; ICC/image/audio inference is not performed. Python mirrors the detached-store transaction. See Metadata Translation.
Target-bound image-geometry translation: translate_xmp_image_geometry(...)	openmeta/metadata_translation.h, openmeta/metadata_transfer.h	Experimental	Transactional v1 projection of exact XMP orientation and complete stored-raster dimensions into canonical native TIFF/EXIF SHORT and LONG groups. Active values must agree with caller-provided TransferTargetImageSpec facts; standard/portable aliases, incomplete pairs, tombstones, conflicts, and limits are explicit. Display-oriented dimensions are never inferred or swapped. Python remains a thin detached-document wrapper. See Metadata Translation.
Reverse descriptive translation: translate_xmp_descriptive_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 projection of exact default-language title/description/rights, indexed creators/keywords, credit, and source into bounded IPTC-IIM datasets. Repeated cardinality, dirty tombstones, byte limits, conflicts, and UTF-8 charset declaration are explicit; unsafe legacy charset reinterpretation fails atomically. Python remains a thin detached-document wrapper. See Metadata Translation.
Reverse location translation: translate_xmp_location_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 projection of five flat IPTC Core location properties into native IPTC-IIM. Reuses descriptive policies, statuses, and result diagnostics with separate location options. Exact singleton paths, byte limits, country-code syntax, dirty tombstones, and charset safety are explicit; structured locations and GPS are outside the contract. Python provides the same operation. See Metadata Translation.
Reverse editorial translation: translate_xmp_editorial_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 Headline, Instructions, and TransmissionReference writeback with independent editorial options. Reuses descriptive policies/results, exact singleton validation, UTF-8 safety, and resource limits. Python provides the same operation. See Metadata Translation.
Combined IPTC translation: translate_xmp_iptc_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 writeback of 20 text/priority groups, adding creator job title, caption writer, category, supplemental categories, and urgency. Independent flags, shared charset/resource limits, and cross-group atomicity. Existing subgroup/date contracts are unchanged. Python provides the same operation. See Metadata Translation.
Structured location reconciliation: translate_xmp_structured_location_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 projection of one explicitly selected structured record into five flat XMP/native IPTC pairs. Record kind/index, paired conflicts, dirty leaf removal, text limits, and charset safety are explicit. Python provides the same operation. See Metadata Translation.
Primary GPS translation: translate_xmp_gps_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 latitude/longitude and altitude/reference writeback. Exact rational precision, paired source/native reconciliation, GPS version handling, and resource limits are explicit. Python provides the same operation. See Metadata Translation.
GPS time/navigation translation: translate_xmp_gps_navigation_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 UTC date/time, speed/unit, track/reference, and image direction/reference writeback. Exact precision, UTC rollover, version support, paired conflicts/removal, and portable reference aliases are explicit. Python provides the same operation. See Metadata Translation.
Destination GPS translation: translate_xmp_gps_destination_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 destination coordinates, bearing/reference, and distance/unit writeback. Exact precision, paired conflicts/removal, version retention, and historical distance-label compatibility are explicit. Python provides the same operation. See Metadata Translation.
GPS quality translation: translate_xmp_gps_quality_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 status, measurement mode, DOP, differential correction, and horizontal error with explicit enum, precision, version, and removal contracts. Python provides the same operation. See Metadata Translation.
GPS text translation: translate_xmp_gps_text_metadata(...)	openmeta/metadata_translation.h	Experimental	Transactional v1 satellites, map datum, processing method, and area with explicit ASCII/Unicode encoding, version, conflict, and removal contracts. Python provides the same operation. See Metadata Translation.
LightSource translation: translate_xmp_light_source_metadata(...)	openmeta/metadata_translation.h	Experimental	One bounded LightSource SHORT with explicit code/label ambiguity, typed conflicts and removal. See Metadata Translation.
Sensitivity translation: translate_xmp_sensitivity_metadata(...)	openmeta/metadata_translation.h	Experimental	Version 2 seven-tag sensitivity group with explicit companions, LONG limits, whole-group conflicts and atomic removal. See Metadata Translation.
Camera/lens/spectral text translation: translate_xmp_camera_text_metadata(...)	openmeta/metadata_translation.h	Experimental	Version 2 six-field printable-ASCII transaction with bounded lens lifecycle, with exact namespaces, explicit aliases, typed conflicts, bounds and removal. See Metadata Translation.
Flash translation: translate_xmp_flash_metadata(...)	openmeta/metadata_translation.h	Experimental	Version 2 scalar or five-child Flash writeback with explicit bitfield, conflict, and removal rules. See Metadata Translation.
Capture rational translation: translate_xmp_capture_rational_metadata(...)	openmeta/metadata_translation.h	Experimental	Four exact unsigned capture rationals with explicit sentinel, precision, conflict, and removal rules. See Metadata Translation.
Capture settings translation: translate_xmp_capture_settings_metadata(...)	openmeta/metadata_translation.h	Experimental	Twelve closed SHORT camera-setting enums with atomic conflicts/removal and Python support. See Metadata Translation.
Structured location construction: translate_xmp_location_to_structured_metadata(...)	openmeta/metadata_translation.h	Experimental	Five flat XMP fields into an explicit Created/Shown record with dense indexes and atomic removal. See Metadata Translation.
EXIF/TIFF orientation helpers: interpret_exif_orientation(...), exif_orientation_name(...), exif_orientation_rotation_degrees_cw(...), exif_orientation_rotation_only(...)	openmeta/orientation.h	Stable	Small utility contract for user-facing orientation labels, clockwise rotation degrees, mirrored-state detection, dimension-swap detection, and rotation-only fallbacks. Python exposes the same helpers through thin scalar/dictionary wrappers.
EXIF/TIFF/DNG numeric value names and version formatting: exif_tag_numeric_value_name(...), exif_tag_numeric_value_format(...), exif_tag_byte_value_format(...), and focused helpers	openmeta/exif_value_names.h	Stable	Small helper contract for common enum-like TIFF/EXIF/DNG numeric values such as compression, photometric interpretation, planar configuration, exposure program/mode, metering mode, light source, flash, color space, white balance, scene capture type, gain control, CFA layout, and DNG calibration illuminants, and EXIF 3.1 lens-correction / noise-reduction status values, plus selected bounded Canon/Nikon/ Sony/Fujifilm/Pentax/Olympus/Panasonic/Phase One/Kodak/Minolta/Sigma/ Samsung/Ricoh/Apple/FLIR/JVC/GE/Reconyx/Microsoft/Motorola/Nintendo/Sanyo MakerNote contexts including NikonSettings On/Off labels, Reconyx scalar labels, Microsoft stitch labels, Motorola CustomRendered labels, Nintendo category labels, Sanyo public-context scalar labels, current Canon RF lens-type labels, current Nikon Z LensData0800 LensID labels, and an ambiguous Pentax Sigma/Samsung/Tokina lens-family label where stable. Version/firmware helpers format selected standard EXIF byte-version fields, Nikon version-like payloads, Olympus packed firmware values, and native RAF firmware payloads without treating formatted versions as enum labels. Unknown or ambiguous values return an empty string or false and remain lossless metadata.
Photoshop IRB decode: decode_photoshop_irb(...) and measure_photoshop_irb(...)	openmeta/photoshop_irb_decode.h	Experimental	Bounded resource traversal with stable raw resource preservation behavior, but the interpreted subset can still grow. Current interpretation includes fixed-layout resource fields, display/grid/thumbnail/color-sampler headers, working-path and numbered clipping-path byte counts / record summaries, descriptor-header summaries plus safe descriptor class-name/class-ID/ item-count fields, bounded descriptor item bodies for bool, long, comp, doub, UntF, TEXT, enum, type, and GlbC, opaque alis and tdta byte counts, descriptor item type-name/type-code fields, ordered bounded obj property, class, enumerated, offset, identifier, index, and name reference fields with per-value and aggregate limits, parsed maximum depth, and parsed per-type counters, nested object/list traversal with item path/depth/list-index and parsed-value count fields, XMLData, ImageReady ASCII text resources, Lightroom workflow text, Macintosh PrintInfo, Macintosh NSPrintInfo, Windows DEVMODE, alternate duotone-color, alternate spot-color, and obsolete Photoshop tag byte counts, legacy halftone/transfer/duotone/EPS byte summaries, embedded IPTC/ICC/EXIF/EXIF2/XMP byte-count fields, and optional embedded IPTC-IIM, XMP, and ICC payload decode.
Semantic metadata query: query_metadata(...), query_crop_metadata(...), and focused query helpers	openmeta/metadata_query.h	Experimental	Query contract for inspection matches plus normalized candidates. Current coverage includes crop/active-area/border margins, exposure/gain, white balance, color/profile/source-color-transform, lens correction, orientation, descriptive EXIF/IPTC/XMP fields including exact contact/event/person/organization/product/artwork/ rights/license/credit/source/rights-expression/release semantics, container-graph evidence for BMFF content-bound metadata and multi-image scene policy, and RAW/source-processing metadata across standard tags, selected DNG tags, RAW value curves, RAW linearity limits, RAW calibration curves, RAW curve control points, EXIF color-space evidence, ICC header/tag entries, XMP ICC/profile/color-space fields, XMP camera RAW profile/look/tone-curve fields, PNG profile text carriers, Fujifilm RAF raw crop/zoom rectangles, Canon aspect/crop metadata, Canon AF micro-adjustment, Canon ambience-selection, Canon ColorData source color-transform, NikonSettings source-processing aliases, Nikon Capture crop bounds, Sony panorama crop margins, selected decoded vendor/MakerNote exposure names, crop/border XMP paths, and vendor RAW-processing classification. Semantic Query uses deterministic tag, namespace, and name matching; tolerant partial matching is isolated in the separate Fuzzy Search API so near names cannot change metadata meaning. Matches retain exact_match, fuzzy_match, and fuzzy_score compatibility fields. Exact rights/license/credit/source matches may have zero matched_terms because the stable 32-bit legacy term mask is full; their explicit semantic and confidence remain authoritative. Grouped candidates include matrix_set, vector_set, and table shapes for related non-crop metadata, including RAW black/white levels, linearization, raw value curves, raw linearity limits, raw calibration curves, raw curve control points, CFA/sensor layout, source geometry, raw-storage identifiers, and source-processing buckets, and per-family vendor MakerNote/RAW white-balance, source-color-transform, raw-storage, sensor, computational, thermal, stitch/panorama, and source-processing groups. Matrix/vector/table groups are promoted only when the available numeric payloads meet conservative minimum shapes, so malformed color matrices, white-balance vectors, and lens-correction records remain per-entry inspection data instead of becoming normalized groups. Long-tail source color/style/lens/source-processing aliases such as camera-to-XYZ/RGB matrices, creative/picture style, film simulation, dynamic-range, optical-correction, AF micro-adjustment, ambience selection, Canon ColorData, NikonSettings, and raw-development terms are classified for query and transfer-policy inspection; camera RAW profiles, looks, tone curves, and vendor source color tables use the explicit source_color_transform semantic, RAW curve/linearity metadata uses dedicated RAW-processing semantics, and computational, thermal, and stitch/panorama fields use explicit source-processing subroles. Python Document and TransferSourceSnapshot mirror this as thin dictionary-returning wrappers.
Structured metadata interpretation records: interpret_metadata(...) and interpret_metadata_query(...)	openmeta/metadata_interpretation.h	Experimental	Thin structured projection over semantic query candidates. Records carry query class, semantic kind, normalized shape, confidence, source entry ids, and normalized origin/size/rect/margins/value arrays where available. Current scope covers orientation, geometry/crop/border including Fujifilm RAF, Canon, Nikon Capture, and Sony panorama geometry patterns, exposure/gain, color/white-balance/profile/source-color-transform records, lens-correction, and RAW/source-processing records including raw value curves, linearity limits, calibration curves, curve control points, computational, thermal, and stitch/panorama subroles, and grouped vendor-family table/vector records where classification supports them. Python Document and TransferSourceSnapshot expose matching dictionary wrappers.
Cross-family concept resolution: resolve_metadata_concepts(...) and resolve_metadata_concept(...)	openmeta/metadata_concepts.h	Experimental	First bounded resolver for duplicated host-facing concepts. Current scope reports candidates, candidate source entries, source families, preferred entries, normalized numeric/text keys, full normalized value vectors, transfer hints, RAW applicability states, normalized date/time fields, date/time precision including bounded subsecond digits, timezone kind, normalized geometry fields, normalized exposure values, and same-role conflicts for orientation, date/time, exposure/gain, color/profile/source-color-transform, GPS, descriptive fields, geometry, lens-correction, RAW-processing, and container-graph evidence across EXIF, XMP, IPTC, ICC, PNG text, BMFF fields, and query-backed interpretation records where applicable. Exposure candidates cover exposure time, aperture, ISO sensitivity, exposure bias, exposure program/mode, gain, and raw exposure-adjustment roles across standard EXIF/DNG/XMP evidence and selected decoded vendor/MakerNote exposure names. Standard EXIF exposure program/mode and gain-control values plus selected Canon/Nikon/Sony/Fujifilm/ Pentax/Olympus/Panasonic/Phase One/Kodak/Minolta/Sigma/Samsung/Ricoh MakerNote values include human-readable labels where stable. Capture exposure facts are safe, while raw/DNG exposure adjustments stay rendered-unsafe. Geometry candidates cover crop, active area, border, and sensor geometry with canonical origin, size, rect, and margin fields when available, including normalized DNG, Phase One/Leaf, Fujifilm RAF, Canon, Nikon Capture, and Sony panorama geometry patterns. Candidate transfer hints distinguish safe, source_bound, rendered_unsafe, and requires_target_image_spec evidence, with compatible-file and rendered-image safety booleans. Color/white-balance, source-color-transform, lens-correction, RAW-processing, and container-graph concepts preserve source evidence for host inspection; source-bound color transforms and RAW curve/linearity/calibration roles are marked rendered-unsafe, computational, thermal, and stitch/panorama RAW-processing roles are marked source-bound, and BMFF whole-scene, primary-component, and per-component content-bound metadata / multi-image policy plus derived-image construction and tiled-image configuration fields are marked source-bound. RAW curve/LUT-like concept roles are conservatively marked conditional_on_raw_encoding until a raw data descriptor can confirm whether they affect the stored samples. Descriptor-aware overloads accept MetadataRawDataDescriptor and can collapse supported stored-RAW descriptors to applies_to_stored_raw or rendered descriptors to not_applicable_to_stored_raw, or compressed-only descriptors to not-applicable when the supplied storage encoding is uncompressed or packed, and primary-plane-only descriptors to not-applicable when the supplied plane index is non-primary. Matching EXIF OffsetTime* and SubSecTime* entries are assembled with DateTime* candidates. Offset-aware conflicts compare normalized UTC instants, while missing timezone or subsecond fields remain lower-precision evidence. EXIF and XMP GPS date/time are combined from same-scope GPSDateStamp plus GPSTimeStamp entries, IPTC digital-creation date/time and XMP DateTimeDigitized map to the Digitized date/time role, and GPS altitude candidates expose altitude-reference code plus below-sea-level state when reference metadata is present. Camera position, EXIF/XMP destination coordinates, and IPTC Extension LocationShown / LocationCreated coordinates use distinct roles. Structured candidates expose location_scope, and conflict/preference handling compares values only within the same scope; metadata_concept_gps_altitude_reference_name(...) provides a stable display token for the reference code. The Descriptive kind reconciles standard title, headline, description, creator, keyword/subject, created/shown location, copyright, rights/license, credit, and source fields. Localized scalars compare per normalized language; creator, keyword, location-identifier, rights-holder, and licensor collections preserve distinct values and select one preferred source per duplicate normalized value. Structured descriptive members expose record_kind and record_scope so related values remain associated, plus policy sensitivity independent of technical transfer safety. It is intended for inspection UI and host policy decisions; it does not rewrite metadata or hide ambiguity. Python Document and TransferSourceSnapshot expose matching dictionary wrappers, including subsecond, location-scope, and record-scope and language fields and the thin MetadataRawDataDescriptor object with storage, compression, and plane-binding fields.
Bounded fuzzy entry search: fuzzy_search_metadata(...), metadata_fuzzy_search_available()	openmeta/metadata_fuzzy_search.h	Experimental	Optional RapidFuzz-backed search over decoded metadata names and property paths. The API has bounded query/candidate/result sizes, caller-selected score cutoff, deterministic top-k ordering, stable entry-id ties, explicit exact/curated-alias/general-fuzzy provenance, and status returns for unavailable, invalid, short, long, or non-ASCII queries. The current normalization contract is locale-independent ASCII with separator, camel-case, and acronym-boundary normalization but without Unicode normalization or transliteration. Calls use local state and are safe against an immutable finalized store. Python Document and TransferSourceSnapshot expose thin dictionary wrappers.
Transfer concept diagnostics: transfer_concept_diagnostics_from_store(...), transfer_concept_diagnostic_message(...), transfer_concept_diagnostic_token(...), transfer_concept_diagnostic_message_token(...), transfer_concept_diagnostic_message_arguments(...)	openmeta/metadata_transfer.h	Experimental	Preflight view over concept candidates for TransferSafetyMode. Each diagnostic reports concept kind/role, transfer hint, keep/drop/requires-target-image-spec action, reason token, severity token, stable host-facing summary token, stable localization message token, localizable argument tokens, default message text, conflict flag, source entries, structured-location scope, generic structured-record scope, and language where applicable, compatible/rendered safety booleans, RAW applicability state, and GPS altitude-reference presentation fields. Descriptor-aware overloads accept MetadataRawDataDescriptor and make RAW-processing keep/drop decisions reflect the supplied stored-RAW, compressed-only, primary-plane-only, or rendered storage context. PrepareTransferRequest::source_raw_data_descriptor can apply the rendered-source RAW filtering and, since 0.5.13, recognized curve/linearity compression and primary-plane restrictions during prepare_metadata_for_target(...); it is still intentionally conservative and does not prove vendor curve/LUT activity for a specific compression mode or decoder stage. Rendered-transfer drop messages distinguish source color transforms, white balance, lens-correction records, source RAW curves/linearity metadata that still require storage-context confirmation, and BMFF content-bound/multi-image scene/derived-image construction/tiled-image configuration policy, plus computational/thermal/stitch source-processing drops from generic source-processing metadata. Python Document and TransferSourceSnapshot expose transfer_concept_diagnostics(...) dictionaries with severity_name, token, message_token, message_arguments, message, location_scope, record_scope, language, and RAW applicability fields, with overloads that accept the thin MetadataRawDataDescriptor object. Python transfer helpers also accept source_raw_data_descriptor for prepare-time filtering.
Vendor RAW-processing summaries: vendor_raw_processing_from_store(...), classify_vendor_raw_processing_field(...)	openmeta/vendor_raw_processing.h	Experimental	Conservative grouped source-RAW/source-processing field summaries for decoded Sony, Canon, Nikon, Fujifilm, Pentax, Panasonic, Olympus, Kodak, Minolta, Sigma, Samsung, Ricoh, Apple, DJI, Google, FLIR, Casio, Sanyo, KyoceraRaw, Reconyx, HP, JVC, GE, Motorola, Nintendo, and Microsoft MakerNotes, including vendor-private, computational, thermal, preview, face-geometry, stitch/panorama, Apple computational capture/HDR/motion, DJI pose/thermal, Google HDR+/shot-log, pixel-shift/multi-shot/ composite/auto-lighting/source-style processing, and FLIR radiometric/raw-value buckets. Long-tail aliases cover source color/style, camera-to-XYZ/RGB matrix, white-balance gain, optical/lens correction, dynamic-range, and raw-development terms. Direct field classification also recognizes decoded Phase One/Leaf RAW-processing tags; use the dedicated Phase One/Leaf helpers for normalized geometry and processing summaries. Intended for audit/UI and rendered-transfer safety decisions, not for writing vendor RAW/source-processing values into rendered targets.
Transfer safety audit: transfer_safety_audit_from_store(...)	openmeta/metadata_transfer.h	Experimental	Preflight summary of source entries and entries filtered or invalidated by TransferSafetyMode, including Sony/Canon/Nikon/Fujifilm/Pentax/Panasonic/Olympus/Kodak/Minolta/ Sigma/Samsung/Ricoh/Apple/DJI/Google/FLIR/Casio/Sanyo/KyoceraRaw/ Reconyx/HP/JVC/GE/Motorola/Nintendo/Microsoft RAW/source-processing buckets. Intended for diagnostics and host UI before preparing rendered-image transfers.
MakerNote transfer audits: makernote_transfer_audit_from_store(...), makernote_layout_transfer_audit_from_store(...)	openmeta/metadata_transfer.h	Experimental	The generic audit reports raw opaque payload and decoded-only entry counts plus current rewrite trust capabilities. The layout audit recognizes canonical Nikon type 1 outer-TIFF-relative notes and type 3 notes with an embedded TIFF at byte 10; bounded embedded-TIFF validation covers standard directory/value offsets only. It also recognizes plausible Canon source-dependent IFD notes when the EXIF camera make is Canon, but reports their source offset basis as ambiguous and does not mark them rewritable. The writer still cannot reconstruct decoded fields, relocate vendor-private offsets, repair checksums, prove semantic readability, or pass MakerNotes through as raw carriers. Python Document and TransferSourceSnapshot expose matching thin dictionary wrappers.
Raw-carrier passthrough audit: raw_carrier_passthrough_audit_from_snapshot(...)	openmeta/metadata_transfer.h	Experimental	Diagnostic preflight for opt-in raw carriers. Reports candidate carriers and primary block reasons such as missing payload, target incompatibility, safety filtering, content-bound C2PA, explicit profile policy, missing decoded-entry links, or unsupported carrier kind. Hosts can call it directly before enabling snapshot passthrough.
Decoded source snapshot state: TransferSourceSnapshot	openmeta/metadata_transfer.h	Stable v1 profile	Stable decoded-store state for positional read, persistence, and reconciliation. Optional raw-carrier records are preserved as data, but raw-carrier passthrough policy remains experimental. Const reuse is safe when callers do not mutate the snapshot.
File/bytes/build snapshot helpers: read_transfer_source_snapshot_file(...), read_transfer_source_snapshot_bytes(...), build_transfer_source_snapshot(...)	openmeta/metadata_transfer.h	Experimental	Convenience entry points outside the narrow positional Host Adoption Profile.
Versioned source snapshot persistence: serialize_transfer_source_snapshot(...), deserialize_transfer_source_snapshot(...)	openmeta/metadata_transfer.h	Stable v1	Target-neutral canonical v1 representation with transactional bounded parsing and an exact compatibility vector. Preserves store blocks, duplicate order, typed values, provenance, tombstones, flags, and optional raw-carrier links. Unknown versions are rejected atomically.
Fileless preparation: prepare_metadata_for_target_snapshot(...)	openmeta/metadata_transfer.h	Experimental	Intended for hosts that already decoded metadata and want to prepare transfer artifacts without reopening the source file. TransferRawCarrierPassthroughMode::WhenSafe is an opt-in snapshot mode; the current writer path only reuses eligible non-C2PA JUMBF and draft unsigned C2PA invalidation carriers for JPEG, JXL, and BMFF targets, plus draft unsigned C2PA invalidation carriers for WebP.
Snapshot execution: execute_prepared_transfer_snapshot(...)	openmeta/metadata_transfer.h	Experimental	Intended for deferred save/writeback from a reusable decoded source snapshot.
Bundle execution: execute_prepared_transfer_bundle(...)	openmeta/metadata_transfer.h	Experimental	Intended for hosts that already own a prepared bundle and destination bytes. Treat bundles as immutable except through documented patch helpers.
Typed adapter operation schema: PreparedTransferAdapterOp, TransferAdapterOpKind, kPreparedTransferAdapterContractVersion	openmeta/metadata_transfer.h	Stable v1 schema	Enum-based insertion operations with explicit marker, tag, box, chunk, item, property, and payload sizing fields. Stable hosts obtain payload and EXR name/type/value views through PreparedTransferHandoff; codecs do not parse route strings.
Adapter-view execution: build_prepared_transfer_adapter_view(...), validate_prepared_transfer_adapter_view(...), get_prepared_transfer_adapter_exr_attribute_view(...), and emit_prepared_transfer_adapter_view(...)	openmeta/metadata_transfer.h	Experimental	Builds and validates the stable v1 operation schema over an experimental prepared bundle. Construction and payload resolution remain coupled to the broader prepared-bundle model.
Generated transfer payload internals, route strings, low-level package chunks, and diagnostic counters not documented by a stable API page	openmeta/metadata_transfer.h	Internal	These fields may be useful for tests and diagnostics, but they are not a compatibility contract for downstream integrations.

Structured descriptive record kinds cover creator contacts, events, people, organizations, products, artwork/objects, rights expressions, rights holders, licensors, licensees, licenses, releases, end users, image creators, image suppliers, image assets, controlled-vocabulary terms, registry entries, image regions, resource references, resource events, manifest items, versions, editorial workflows, source software, editorial contacts, technical-image, audio-asset, preview-asset, and pantry records. The IPTC technical records normalize image layout, component count, audio channel/rate/resolution/ duration, preview format/version, and bounded binary payload identity without treating IPTC layout as EXIF rotation. Sensitivity is mirrored in transfer diagnostics and thin Python dictionaries. Hosts must not interpret a safe transfer hint as approval to publish personal-contact, person-identity, location, or legal-rights metadata.

Exact descriptive query semantics also cover legacy editorial workflow pairs, non-equivalent IPTC taxonomy and workflow fields, scoped prior-envelope references and originating software, IPTC Core accessibility and taxonomy fields, IPTC Extension registry and image-region entities, resource/document identity and lineage/history, and remaining bounded PLUS party, delivered-asset, and license-policy fields. Legacy IPTC image, audio, and preview datasets use exact technical_image, audio, and preview semantics. Equivalent scalar pairs participate in preference/conflict handling; taxonomy, resource-identifier, and license-document collections remain additive. Document identity/lineage/history, registry, prior-envelope-reference, and source-software records are source-bound for rendered transfer; image-region records require target image specifications. Editorial contacts carry personal-contact sensitivity independently of their technical transfer hint. Technical-image, audio-asset, and preview-asset records are source-bound.

The bounded BMFF tiled-image field contract covers tilC version 0 tile dimensions, up to eight extra dimensions, dref/deti mapping, internal tile_item_type/tipa associations, bounded external URL components, logical offset-table rows, explicit or sequentially inferred tile sizes, and separate core/layout/complete validity. Offset-table validation is capped at 262144 entries, emitted rows at 64, property associations at 64, and retained URL components at 512 bytes. TiledImageConfiguration remains an experimental source-bound concept role exposed unchanged by the thin Python enum.

Practical guidance

Use stable APIs for normal application integrations. Use experimental APIs when they match a real workflow and the integration can track OpenMeta releases. Avoid internal surfaces unless you are contributing to OpenMeta itself or writing a test that is intentionally tied to implementation details.

High-throughput hosts should use Host Adoption Profile for read/state compatibility and Prepared Transfer Handoff for stable target preparation, then query format capabilities separately.

Image Encoding and Composite Translation (0.5.7)

translate_xmp_image_encoding_metadata and translate_xmp_composite_metadata are experimental v1 APIs with thin Python wrappers. Six typed native fields, exact rationals, group dependencies and bounded binary exposure lists share validation and portable-output rules. EntryFlags::ValueBigEndian preserves raw big-endian exposure bytes. Snapshot v1 layout remains unchanged, but a snapshot carrying this new flag needs a 0.5.7 or later reader. See Metadata Translation.

Structured Capture Update (0.5.8)

OECF, SpatialFrequencyResponse, CFAPattern and DeviceSettingDescription add four native targets in one transaction through translate_xmp_structured_capture_metadata and its Python counterpart. The 0.5.8 combined inventory was 65 distinct native tags across fifteen APIs (62 retained by compatible-file transfer). ABI 3 and host synchronization remain unchanged; big-endian snapshots for these four tags need a 0.5.8 reader. See Metadata Translation for the encoding, bounds and conflict contract.

EXIF Text Update (0.5.9)

The 0.5.9 text/version batch adds UserComment, both version fields and seven EXIF 3 text tags. The new EXIF text API also supports UTF-8 owner/lens fields. The combined capture inventory is 75 distinct ExifIFD tags across sixteen APIs; compatible-file transfer retains 72. Version and Artist/Software companion requirements are explicit. ABI 3, snapshot v1 layout and host synchronization responsibilities remain unchanged. BOM-less big-endian UserComment snapshots require a 0.5.9 reader. See the EXIF text/version translation contract for limits and the recorded OIIO/ExifTool reader limitations.

EXIF 3.1 LearningOptOutIn and Profile Authoring Update (0.5.12)

The experimental LearningOptOutIn and profile translation contracts are versioned by kMetadataLearningOptOutInTranslationContractVersion == 1 and kMetadataProfileTranslationContractVersion == 1. ABI 3, snapshot v1 and host-owned synchronization remain unchanged. The contracts are bounded and transactional, but they do not impose mandatory complete-file companions, rewrite arbitrary RDF, infer ICC/image/audio authority, or close downstream OIIO/iRAW acceptance. See Metadata Translation.

EXIF 3.1 Development and Correction Update (0.5.11)

The experimental translate_xmp_development_correction_metadata contract and its Python counterpart add A40D-A412 with a packed DevelopmentType resource, the published DevelopmentCharacterstic spelling, UTF-8 type-129 description and bounded correction codes. Selected writeback requires an explicit host version of 0300 or 0310. The translator never changes ExifVersion. ABI 3, snapshot v1 and host-owned synchronization remain unchanged. See Metadata Translation.

Standard Validation Update (0.5.10)

Fixed schemas now cover 64 existing reverse targets, five registered Interop fields and three structural pointers. Authoring, typed editing and canonical serialization reject malformed known fields that previously followed the unknown-tag policy. Strict unknown-tag validation accepts valid fields in this batch. Native enum and value checks also govern portable-output eligibility. This is a validation behavior change; public signatures, ABI 3, snapshot v1 layout and host synchronization responsibilities are unchanged. Detached validation does not enforce mandatory complete-file companions. See Generic Typed Metadata Authoring for the bounded validation contract.