Three gaps found while measuring the record path against the file path, each one
a signal the library could not see:
WebP stores `XMP ` after the pixels, so on any WebP above the scan window a fixed
read stops short of the label. `_riff_late_metadata` steps over the coded image to
reach it, the RIFF analogue of the existing PNG and ISOBMFF readers. Three corpus
files hid an IPTC "Made with AI" tag and a C2PA `trainedAlgorithmicMedia` there.
The decoder-backed fallback now covers only what it is actually for -- metadata the
raw bytes do not spell, such as a compressed PNG `zTXt` packet.
A C2PA reader failure returned the same `None` as a file with no manifest, so a
verdict could fall back to the raw byte scan with no trace anywhere. Failures now
log at warning and only genuine ones do: a file without credentials never reaches
that branch, and an unsupported container is demoted to debug through the reader's
own `C2paError.NotSupported`. The first corpus run with it found a truncated PNG.
`scan_dataset.py` never registered the pillow-heif opener it declares as a
dependency, so every HEIC was scanned as unreadable -- no EXIF, and a pixel layer
that was 397 of 406 features NaN instead of 136.
`_riff_late_metadata` caps its total like `isobmff.scan_c2pa_region` does. Clamping
each chunk to the bytes remaining is not enough on its own: one chunk can declare a
length spanning most of the file, and this runs on the memoized verdict path over
images from arbitrary sources.
Also lands `identify_metadata_record` and `ProvenanceReport.to_dict()`, the
one-call entry point and the versioned JSON contract for the record path.
Record-vs-file equality holds over 3,478 corpus images, and the eight files these
fixes recovered still report AI.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
`collect_metadata_record` returns a JSON-safe record carrying an image's
provenance metadata regions -- never its pixels -- and the existing
`evidence_from_metadata_record` + `identify_from_evidence` build the verdict
from it without opening the file. The contract is equality with
`identify(path, metadata only)`, verified over the tracked fixtures and over a
local corpus of 3,478 images (every file carrying a rare signal, plus a random
slice): zero differences.
Three placements defeated earlier drafts and each is now a rule with a test:
the `scan_head` buffer is the head CONCATENATED with late metadata, so a
structural walk must read the raw head instead; Samsung splits its evidence
between a post-EOI trailer and the coded scan; and PIL's info keys must be
emitted in the file path's candidate order, since the first token match wins.
Also fix a real detection gap found while establishing that equality: a label
the decoder can read but a raw byte scan cannot -- a compressed PNG `zTXt`
packet, or a WebP XMP chunk past the scan window -- was invisible to
`identify`. Eight corpus files carrying a China TC260 AIGC label or an IPTC
"Made with AI" tag were reported as no signal at all.
`scripts/detection_timing.py` and its report script measure the metadata path
per method; they write outside the repository and are read-only over a dataset.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Every code-referencing claim in the docs, the README and the rules files was
checked against src/, and each finding was re-derived independently before it
was applied. 35 held, 5 were false positives.
Two of them were code, not text. `InvisibleOptions` promises in its docstring to
mirror `InvisibleEngine`, and two defaults had silently stopped:
`max_resolution=None` reached `_target_size`'s `max_resolution > 0` and raised
`TypeError` on every library call that left the options alone, and
`cpu_offload=True` made a library run slower than the identical CLI run. Both are
fixed, and `TestInvisibleOptionsMirrorTheEngine` compares the two signatures
field by field rather than pinning the two values that happen to be known. A
companion assertion in `TestTargetSize` reads the engine's own declared default,
so a drift on the engine side -- which the mirror check alone would accept,
because both sides would still agree -- fails too.
The user-facing docs: README called `invisible` GPU-optional where it raises
without CUDA, and gave the image `metadata` command `video metadata`'s output
rule, promising the source survives a command that overwrites it. Yuanbao was
missing from the supported-mark list. `veo` was listed among the video policies
that require a run anchor, though its row sets no `anchor_iou`.
`known-limitations` called ControlNet the default profile and contradicted
itself ninety lines below. An unescaped pipe truncated the `hailuo` table row.
The `dev` extra, the CI shape, ffmpeg's role, the sdist boundary and the
strength-curve range were corrected, and `remove_all`/`remove_batch`, the pill
gate, `erase --keep-metadata` and `all`'s CUDA failure mode were documented.
Research notes that described removed modules, extras and flags in the present
tense now say so once in the page banner instead of sentence by sentence, which
covers the whole page rather than the lines that happened to be noticed, and one
fixture is referred to by role rather than by name.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
The visible-mark path had grown three copies of one ladder sweep, four
near-identical `detect` arms, and four hand-rolled `footprint_mask` overrides;
mark knowledge sat in five hand-maintained tables across three modules; and the
flagship `all`/`batch` pipeline existed only in cli.py, written twice with
divergent behavior.
Detection is now one measurement. `_ladder_best` replaces the three sweeps,
`_scan`/`_verdict` replace the four arms, and the winning box travels to the
mask on `TextMarkDetection.match_box` instead of being swept a second time.
`detect_both` returns the strict and relaxed verdicts from one scan, which
halves the arbiter's perception cost (260 -> 130 matchTemplate calls on a 2048²
image, verdicts identical field for field). A per-mark demotion goes in the new
`_post_gate` hook, never in a `detect` override -- an override is invisible to
the single-pass path, which is how the RunningHub and Yuanbao anchor gates
briefly stopped applying.
Everything about a mark is now one registry row: product, label regime, the
platform sentence `identify` reports, the metadata signals that confirm it, and
its TC260 producer codes. `identify._VISIBLE_MARK_PLATFORM`, the signal mapping
in `api.visible_provenance`, `_PRODUCT_OF` and the pill veto are derived from
those rows.
`api.remove_all` / `api.remove_batch` are the library form of the `all` and
`batch` commands; the CLI is a wrapper that owns console text and exit codes.
Progress is a `(stage, detail)` pair of stable tokens, so the CLI keys its
wording off structure rather than parsing the library's prose back.
Two intentional behavior changes, both verified against a recorded 811-image
sample of detector verdicts, removal-mask hashes, arbiter decisions and
`identify` reports:
* A TC260 label now relaxes the vendor its `ContentProducer` names rather than
ByteDance's pair on every China-AIGC image. 333 of 811 samples move; on 185
of them the previously relaxed pair was simply the wrong vendor, and the
mark actually present never reached the relaxed gate its own
`provenance_ncc_factor` was calibrated for.
* A confident LibLibAI detection suppresses the Jimeng pill, like every other
TC260 product's mark. It was registered alongside RunningHub and Baidu, both
of which were added to the hand-written veto list, and it was not. 1 sample
moves, and it is exactly the co-firing case.
Nothing else in that record changes: detector verdicts, mask hashes and
`identify` verdicts are byte-identical, and all 200 calibration constants are
untouched.
Also: `aigc_label` and friends plus `extract_c2pa_info` are memoized on
(path, mtime_ns, size) -- size because this package rewrites in place; the
native TC260 container readers route on magic bytes instead of the file
extension, so a mislabeled AVI or FLV is no longer invisible; `identify` shares
one pixel decode between the DWT-DCT and visible stages (TrustMark keeps its own
Pillow decode, which is not substitutable); and the six `stabilize_*` video
wrappers collapse into one policy table.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
New engines, each calibrated on its TC260 USCC cohort and validated by a
full-corpus sweep (42009 files):
- runninghub: top-left corner (new corner="tl"), faint mid-gray text via
the new raw-grayscale "gray" detection front-end, anchor-position gate
- baidu: text-run-only template (pill is a bright-blob magnet), load-bearing
Doubao+Qwen rival margins, corner-extended footprint for the white tag
- liblib: bottom-center (new corner="bc"), Arial silhouette (font is the
discriminative lever against latin UI text), logo-extended footprint
Qingyan parked (no clean-arm separation at any render/box), MiniMax/Hailuo
parked (1 visible frame, the xinghui rule); silhouettes kept as starting
points.
Two AI-provenance metadata types mined from the retained corpus that
identify previously read as no-signal:
- Dreamina (ByteDance's international Jimeng brand) signs C2PA as
"Bytedance Pte. Ltd." with a "Dreamina/x.y" claim generator and NO
digitalSourceType, so the generator name is the only AI signal. Add a
C2paAiVendor row with a new asserts_ai flag (identity-AI: presence
asserts AI without trainedAlgorithmicMedia) plus the derived
C2PA_IDENTITY_AI_ORGS view, folded into identify's c2pa_is_ai. Keyed on
the Dreamina generator token, not the "Bytedance Pte" issuer, so non-AI
CapCut edits signed by the same entity stay unattributed. 7/7 corpus
files now attribute to ByteDance.
- Tencent Cloud's TC260 AIGC variant uses a ServiceProvider/ServiceUser
schema (vs the producer-side ContentProducer schema), embedded in EXIF
ImageDescription; add those field names to _TC260_FIELDS so the generic
{"AIGC":{...}} gate accepts it. 11/11 corpus files now flagged.
Test-first: reproducing tests in test_identify.py / test_metadata.py.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Deep-research 2026-07-10 (adversarially verified): the Gemini sparkle is
tier-gated (visible on Free/Pro, absent on Ultra/AI-Studio/API; no official
visible-mark detector or published glyph spec); the faint-visible-mark
precision/recall wall is fundamental (learned CNN front-end does not cleanly
separate true/false, arXiv:1705.08593 refuted); learned detectors need large
synthetic-composite datasets + carry off-distribution risk; landscape adds
Meta bottom-left + Samsung star-icon variants; China GB 45438-2025 is the
strongest visible-mark mandate.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Mined from the retained corpus 2026-06-22 (open-world EXIF/PNG-text/XMP scan,
minus the registry): three AI image generators that stamp a plain generator
name and no C2PA, so identify read them as no-signal -- and under the P0#5
no-signal skip would have skipped the scrub.
- NovelAI (anime SD): PNG tEXt Software/Source/Title. exif_generator now reads
PNG text chunks (via img.info), not only EXIF/XMP.
- Reve (reve.com): EXIF Software / XMP CreatorTool. Token is the full
"reve.com", not bare "reve" (would false-fire on "forever"/"reverie").
- Aphrodite AI: EXIF Make / Software.
Detection/removal parity: NovelAI stamps an AI-shaped VALUE under a non-AI KEY
(Title/Source), which _is_ai_key alone keeps. New _is_ai_value drops a text
chunk by value-token match on removal, mirroring exif_generator -- else the
cleaned file still read as NovelAI (verified on a real corpus file).
Tests: TestExifGenerator gains NovelAI PNG-text, Reve, Reve-not-overmatched,
Aphrodite, and a NovelAI detect/remove parity regression. Docs synced
(module-internals, watermarking-landscape, CLAUDE.md).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Deep-research (2026-06-19, adversarially verified) confirms the open imwatermark
dwtDct mark is fragile by scheme, not by our usage: maintainers admit no 100%
clean-decode guarantee; measured ~0.79 bit accuracy clean (~38/48, below our 44
gate). Root causes (code-verified + locally reproduced): per-block max-coefficient
bit read (content flips bits) and YUV chroma 8-bit clamping on bright pixels (the
bright-flat / all-ones failure). No maintained fork or detector does this scheme
reliably (WAVES relegates it to an appendix; learned schemes are a different class;
dwtDctSvd cannot decode SDXL's dwtDct). Conclusion: keep it positive-only, rely on
C2PA. Sources: imwatermark READMEs, arXiv:2406.08337 (WMAdapter), arXiv:2401.08573
(WAVES), diffusers SDXL watermark.py.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Final characterization after a positive-control sweep. The imwatermark dwtDct
round-trip fails (28-39/48, below the 44 gate) not on "high texture" as a prior
note claimed, but on a broad carrier class: the FLUX fox, doubao, a minimalist-FLAT
FLUX generation, AND a clean synthetic bright-flat fill with NO watermark all fail
identically. The degenerate all-ones decode is therefore a CARRIER ARTIFACT, not a
watermark (the no-watermark synthetic image reproduces it; a double-embed test shows
no interference). detect_invisible_watermark is positive-only: trust a hit, treat a
None as inconclusive unless a same-carrier positive control first recovers >=44.
Consequence: whether BFL hosted FLUX embeds the open DWT-DCT is unresolvable with
this detector on the available carriers (textured AND flat FLUX both fail the
control). C2PA stays the reliable FLUX signal. Low priority to chase further.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Earlier notes asserted BFL hosted output has no open DWT-DCT watermark. That was
overstated: the test carriers were high-texture fox images where a clean
encode->decode round-trip of a KNOWN-embedded watermark recovers only 28-35/48
bits (below the safe 44 gate), so the detector would miss a present mark there --
the None is inconclusive, not proof of absence.
Verified positive-control (2026-06-19): imwatermark dwtDct round-trips 48/48 on
synthetic carriers and on chatgpt-1.png (48/48) / firefly-1.png (45/48), but
FAILS on flux-1.png (28/48) and doubao-1.png (39/48). So invisible_watermark
detection is a positive-only signal: trust a hit, treat a miss on busy content as
inconclusive. Affects all open SD/SDXL/FLUX DWT-DCT detection. C2PA stays the
reliable FLUX identifier; whether BFL hosted embeds the open mark is unresolved
(needs a low-texture hosted sample).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Lossless-PNG check across both BFL Playground model lines (FLUX.2 [pro] and
FLUX.1 [dev]) confirms the open DWT-DCT pixel watermark is absent on hosted
output regardless of model or container; only the signed C2PA manifest is present.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
flux-1.png / flux-1.jpg are real Black Forest Labs FLUX.2 [pro] Playground
outputs (signed C2PA, issuer "Black Forest Labs" + trainedAlgorithmicMedia,
manifests verified to contain no personal data). flux-1.jpg is the first
committed JPEG-with-C2PA fixture, exercising the c2pa-python non-PNG reader path
end to end. Regression tests assert both attribute to "Black Forest Labs (FLUX)".
Also documents the verified finding (n=2, 2026-06-19): BFL's hosted output carries
the signed C2PA manifest but NOT the open invisible-watermark DWT-DCT (decodes to
degenerate all-ones, chance-level vs the FLUX reference) -- the open pixel mark is
dev-inference-code-optional only. So a hosted FLUX.2 image is identified by C2PA
alone, with no open-pixel fallback once C2PA is stripped.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Mining the local production corpus (25,725 imgs) surfaced two AI vendors signing
C2PA that the registry missed:
- Canva (Magic Media) signed "Canva" + trainedAlgorithmicMedia -> detected AI but
no platform attributed (disproves the old "Canva exports strip C2PA" assumption).
- BytePlus (ByteDance international: Seedream/Seededit) signs "Byteplus Pte. Ltd.";
the bare volcengine needle missed it, so its output was mis-attributed to "Adobe
Firefly" via an incidental "Adobe XMP" string the fallback byte-scan picked up.
Adding both to C2PA_AI_VENDORS lets the clean manifest issuer attribute them
directly. Corpus re-run: 16 platform changes, all improvements (3 Adobe->ByteDance
fixes, 4 None/TC260->ByteDance, 9 None->Canva), 0 regressions. An attempted
signer-based attribution fallback was measured and dropped: it regressed 18 images
(friendly ByteDance label -> raw Chinese cert org; IPTC tool name pre-empted).
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
