Migrating to OpenMeta 0.7

This guide describes the 0.7 release. For the current minimum-version package policy, see Shared Library Contract.

OpenMeta 0.7.2 retains the unfrozen development ABI label 4. Public C++ layouts and APIs may change while the label stays 4. Rebuild applications and plugins against matching release headers and library when they change; the label alone does not establish compatibility with older ABI-4 binaries. The initial local 0.7.0 build used label 5; 0.7.1 returns to 4 under this policy. The current Windows runtime is openmeta-4.dll; ELF/macOS use ABI major 4.

PreparedTransferBundle carries tiff_exif_removals and tiff_merge_existing_exif. Request find_package(OpenMeta 0.7 CONFIG REQUIRED). SameMinorVersion still rejects 0.6 requests. This discovery rule does not freeze C++ layouts. Keep headers, objects and libraries from matching snapshots.

Timestamp authority

The date and technical translation contracts are version 2. Accepted xmp:CreateDate, XMP exif:DateTimeOriginal and xmp:ModifyDate owners control their complete native timestamp family. Lexical timezone and fraction control offset and subsecond presence. Missing companions create explicit native dirty tombstones, even when their keys were absent from the source store. A dirty owner tombstone removes all three members. Omission preserves the destination. Existing conflict policies remain; accepted absent members carry intent. Accepted clean exact timestamp members are marked dirty to retain merge authority and count as updates against operation limits. Synthesized entries count against added-entry and operation limits. Repeated translation reuses existing dirty tombstones. IPTC and unrelated technical singleton behavior is unchanged.

Each translator is transactional. Hosts stage date and technical calls before publishing a combined result. Fractional dates still require disabling lossy IPTC mappings.

Capture and lens lifecycle (0.7.1)

Capture, Flash, sensitivity and camera-text contracts are version 2. Accepted ExposureTime, FNumber, base ISO, Flash, FocalLength and lens make/model/serial owners create native Dirty+Deleted intent even when native keys are missing. Accepted clean exact values receive same-value Dirty updates that preserve bytes and wire provenance. Omission and conflict policies remain; intent and update costs are checked before transactional publication and repeat calls reuse intents. Hosts stage the separate calls before publishing an aggregate result.

Full sensitivity owns 8827 and 8830–8835 as one validated group; optional absence becomes removal intent after complete validation. Basic ISO owns only 8827 and preserves companions; disable it when full sensitivity owns the source. Lens fields are independent. In 0.7.1, ExposureBiasValue, LensSpecification and camera-owner/body-serial paths retained their prior behavior. The 0.7.2 section below extends ExposureBiasValue.

TIFF preparation merges unspecified destination ExifIFD records for these dirty edits. Bounded removal also accepts 829A, 829D, 8827, 8830–8835, 9209, 920A and A433–A435. MakerNote bytes and standard pointers are preserved as opaque records; private relocation or checksum repair is not provided. See Migrating to OpenMeta 0.7 for the unfrozen development ABI-4 policy.

TIFF edit requests

tiff_ifd0_removals now also accepts IFD0 DateTime 0132. The new tiff_exif_removals list accepts primary ExifIFD 9003, 9004, 9010–9012 and 9290–9292. Both lists must be sorted and unique. Preparation requires exact native IFD keys, Dirty+Deleted flags and enabled EXIF output; live entries win over old tombstones. Snapshot v1 is unchanged.

Preparation enables tiff_merge_existing_exif for exact dirty native timestamp and selected capture/lens members. This mode and per-tag ExifIFD removal preserve unspecified destination entries, including unselected timestamp families, capture fields, standard pointers and opaque MakerNote bytes. Private offset/checksum repair is outside this contract. Existing replacement behavior remains when this mode is off. A present-empty source ExifIFD still requests whole-directory clear; combining it with merge or ExifIFD removal is invalid. Source filtering does not redact preexisting destination records in merge mode.

TIFF/BigTIFF edit, stream and package paths consume both lists. Invalid tags, ordering, duplicates and replacement/removal conflicts fail before output. Fresh emitters, codec handoffs and the DNG SDK adapter reject either nonempty list. Use TIFF editing, including an empty scaffold when creating a fresh file with removal intents. Manual native lists do not implicitly synchronize XMP. Keep input and bundle unchanged between planning and applying, and replan following changes. Python’s path-based probe reports both lists and the flag.

Host-owned synchronization, existing patch/handoff contracts and snapshot encoding stay unchanged. No general multi-page deletion, complete-file profile or codec conformance is implied. See Metadata Editing and Metadata Translation.

APEX and capture-settings authority (0.7.2)

APEX and capture-settings contracts are version 2; general capture is version 3 because its ExposureCompensation mapping shares the APEX bias owner. Each of five APEX fields and twelve closed settings is independent. Accepted dirty owner deletion carries exact native Dirty+Deleted intent even when native keys are missing. Accepted clean exact values gain Dirty with original scalar and wire provenance. Omitted or ineligible owners preserve destination values.

Existing conflict policies, exact APEX units, brightness unknown sentinel, accepted enum codes, aliases and source shapes remain. Added intent, clean-marker promotion and same-value authority updates consume preflight budgets. Repeat calls reuse intent; each translator publishes once or leaves output unchanged. Hosts stage separate calls before aggregate publication and disable one shared ExposureBias mapping when composing APEX and general capture. No inference is performed.

TIFF/BigTIFF uses the existing removal list and merge flag for the added tags: 8822, 9201–9205, 9207, A217, A401–A403, A406–A40A and A40C. The allowlist now has 39 tags. Unselected native records, opaque MakerNote bytes/original offsets, standard pointers and media remain preserved. Snapshot v1, bundle/API layouts, ABI 4, package-minor policy and unsupported-consumer rejection remain unchanged.