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remove-ai-watermarks/docs/python-api.md
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Victor KuznetsovandClaude Opus 5 2668f1302d Read WebP metadata past the scan window and surface C2PA reader failures
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>
2026-08-05 21:10:38 -07:00

19 KiB

Python API

Use the high level API for normal application integration. Low level detector and pipeline modules are intended for maintainers and specialized workflows.

Dependency groups are identical for the CLI and Python API. The default install covers metadata extraction, normalization, verdict logic, and stripping. Array/pixel APIs use pixels; visible removal uses visible; DWT-DCT detection uses detect; invisible image removal uses qwen-zimage and an NVIDIA GPU; and visible video processing uses video. Video SynthID removal is a separate VAE path that still runs on CPU and combines video and diffusion. Add heif independently when path-based pixel APIs must decode HEIC, HEIF, or AVIF. See the complete feature-extra matrix.

Remove visible marks

Install remove-ai-watermarks[visible] before using the visible-removal API.

import remove_ai_watermarks as raiw

result, removed = raiw.remove_visible(
    "watermarked.png",
    "clean.png",
)

The function returns:

  • the result as a BGR NumPy array;
  • a list of labels that were removed.

An empty removed list means that no registered visible mark was selected. It does not prove the image has no metadata or invisible watermark.

Path input

For a path input, remove_visible:

  • reads metadata provenance for the default auto sensitivity;
  • preserves a separate alpha channel;
  • writes the output when an output path is supplied;
  • strips AI metadata from the written output by default;
  • preserves the original bytes for a same-format no-op copy.
result, removed = raiw.remove_visible(
    "watermarked.png",
    "clean.png",
    sensitivity="auto",
    backend="auto",
    strip_metadata=True,
)

Set write_noop=False if the output path must remain untouched when nothing is removed:

result, removed = raiw.remove_visible(
    "input.png",
    "clean.png",
    write_noop=False,
)

Array input

Array inputs are BGR NumPy arrays. They do not carry file metadata or a separate alpha plane:

import cv2
import remove_ai_watermarks as raiw

image = cv2.imread("input.png")
result, removed = raiw.remove_visible(image, backend="cv2")

Run the full pipeline

remove_all is the library form of the all command: visible marks, then the invisible watermark, then AI metadata. Stages are chained through a file in the system temp directory, so a partial result never appears at the output path.

import remove_ai_watermarks as raiw

result = raiw.remove_all("input.png", "clean.png")   # -> RemoveAllResult
print(result.output)          # the path written
print(result.visible_label)   # the marks removed, or None
print(result.invisible)       # "removed" | "no-signal" | "unavailable"

invisible is the field to check. "unavailable" means the GPU extra is not installed, so the output looks processed but still carries the watermark; "no-signal" means the scrub was deliberately skipped because nothing was locally detectable, which is a successful run.

Pass InvisibleOptions to tune the diffusion stage, and engine to reuse one loaded model across many calls:

from remove_ai_watermarks import InvisibleOptions

raiw.remove_all(
    "input.png",
    "clean.png",
    invisible=InvisibleOptions(strength=0.35),
    force=True,
    progress=print,
)

InvisibleOptions carries only what InvisibleEngine itself takes, and uses the engine's own parameter names and defaults. force, which decides whether the engine runs at all, is a parameter of remove_all and remove_batch alongside backend and sensitivity.

If AI metadata survives the strip, remove_all raises MetadataStripIncomplete before writing anything: an AI-readable output is worse than no output.

remove_batch runs one mode over a directory and never lets a single bad file end the run:

summary = raiw.remove_batch("in_dir", "out_dir", mode="visible")   # -> BatchSummary
print(summary.processed, summary.failed, summary.errors)
print(summary.invisible_unavailable)   # outputs that still carry the watermark

mode is all, visible, invisible, or metadata. Pass a constructed InvisibleEngine as engine to load the model once for the whole directory.

Inspect provenance

The default installation evaluates file metadata. Add visible, detect, or trustmark to enable the corresponding optional pixel signals.

Get the vendor keys used by visible removal:

import remove_ai_watermarks as raiw

vendors = raiw.visible_provenance("input.png")

Get the full provenance report:

from pathlib import Path

from remove_ai_watermarks.identify import identify

report = identify(Path("input.png"))
print(report.platform)
print(report.signals)

Use check_visible=False and check_invisible=False for metadata-only inspection through the compatible path-based API:

report = identify(
    Path("input.png"),
    check_visible=False,
    check_invisible=False,
)

Extraction and detection are also available as separate steps. This is useful when a file-reading worker collects the metadata once and another component evaluates the resulting evidence:

from remove_ai_watermarks.identify import (
    extract_provenance_evidence,
    identify_from_evidence,
)

evidence = extract_provenance_evidence(Path("input.png"))
report = identify_from_evidence(evidence)

Collect once, judge elsewhere

collect_metadata_record splits the two halves apart: it is the only step that touches the file, and it returns a JSON-serializable record the verdict can be built from on another machine, in another process, or later.

import json

from remove_ai_watermarks.identify import identify_metadata_record
from remove_ai_watermarks.metadata_record import collect_metadata_record

record = collect_metadata_record(Path("input.png"))   # reads the file
blob = json.dumps(record)                             # ship it anywhere

report = identify_metadata_record(json.loads(blob), path=Path("input.png"))  # reads nothing
payload = report.to_dict()                            # versioned JSON contract

The verdict is the same one identify(path, check_visible=False, check_invisible=False) returns for that file. That equality is the record's whole contract and is verified over the tracked provenance fixtures and a separate local evaluation corpus. ProvenanceReport.to_dict() is the stable service boundary: it adds a schema_version, contains only JSON-safe values, and deliberately omits the local source path.

A record carries metadata regions, never pixels: marker segments before the JPEG scan, every PNG chunk except IDAT, RIFF chunks except the coded image, the ISOBMFF provenance boxes, the container's trailer, the parsed EXIF tags the verdict reads by name, PIL's info mapping, and the C2PA manifest store. Record size is bounded by those metadata regions and trailers; images with large embedded manifests naturally produce larger records.

The path argument is metadata: it labels the report and is never opened by either function, so a record collected elsewhere can be judged against a path that does not exist locally.

If metadata was collected by another component instead, normalize its nested record the same way:

from remove_ai_watermarks.identify import (
    evidence_from_metadata_record,
    identify_from_evidence,
)

record = {
    "pil": {"info:parameters": "Steps: 20, Sampler: Euler"},
    "exif": {"0th": {"Software": "Stable Diffusion"}},
}
evidence = evidence_from_metadata_record(record, path=Path("input.png"))
report = identify_from_evidence(evidence)

The normalizer recursively preserves text and byte values. It also decodes strings prefixed with hex: and fields named base64 or ending in _base64. Diagnostic values under error and kind are ignored because they describe the collector rather than the source file. Pass a C2PA manifest-store dictionary in record["c2pa_store"], or through the explicit c2pa_manifest_store argument.

identify_from_evidence does not reopen the source file by default: it evaluates metadata only, and registered visible marks and pixel-backed invisible watermarks remain in the path-based identify call.

Pass image_path together with check_visible or check_invisible to add those pixel detectors on top of the SAME evidence. That is how a caller asking one file two provenance questions — which vendor is confirmed, and is there an invisible target — pays for the metadata extraction once:

from remove_ai_watermarks.identify import extract_provenance_evidence, identify_from_evidence

evidence = extract_provenance_evidence(source)
metadata_only = identify_from_evidence(evidence)
with_pixels = identify_from_evidence(evidence, image_path=source, check_invisible=True)

Strip metadata

from pathlib import Path

from remove_ai_watermarks.metadata import has_ai_metadata, strip_and_verify

source = Path("input.png")
output = Path("clean.png")

if has_ai_metadata(source):
    output_path, surviving_markers = strip_and_verify(source, output)
    if surviving_markers:
        raise RuntimeError(
            f"AI metadata remains in {output_path}: {surviving_markers}"
        )

Use strip_and_verify when your application reports that stripping succeeded. It checks the written output and returns (output_path, surviving_markers). When the first strip leaves markers in a malformed but raster-decodable image, it normalizes the container through image_io and checks again. That recovery path preserves the pixels but drops standard metadata. Treat a nonempty surviving_markers mapping as a failure.

remove_ai_metadata is the lower level fail-safe transformer. It may copy an undecodable input through unchanged, so its return alone must not be presented as proof that metadata was removed.

Identify and clean video

The high level video API supports MP4, MOV, M4V, WebM, MKV, AVI, and FLV: metadata-only calls work with the default install, while visible identification, removal, and the complete pipeline require remove-ai-watermarks[video].

import remove_ai_watermarks as raiw

report = raiw.identify_video("input.mp4")
print(report.is_ai_generated)
print(report.platform)
print(report.visible_mark)
print(report.metadata_markers)

identify_video uses the same full-clip temporal arbiter as visible removal. It reports a recurring registered mark and supported AI metadata as positive signals. When neither is present, is_ai_generated is None, never False. The absence of a public local video SynthID decoder is included in caveats. Pass check_visible=False for a bounded metadata-only inspection.

For normal product integration, use the complete locally verifiable pipeline:

result = raiw.remove_video_all("input.mp4", "clean.mp4")
if result.remaining_metadata:
    raise RuntimeError(f"AI metadata remains: {result.remaining_metadata}")

The default removes one stable supported visible provider mark when present, always strips verified AI metadata, and writes a same-container output even when neither signal is found. This gives callers one predictable output path. It does not run lossy invisible regeneration by default.

include_invisible=True explicitly adds VAE regeneration for MP4, MOV, or M4V. VideoAllResult.invisible_removed reports whether the oracle-certified SynthID stage ran.

Process a top-level directory sequentially:

batch = raiw.remove_video_batch("videos", "videos_clean", mode="all")
if batch.failed:
    for item in batch.items:
        if item.error:
            print(item.source, item.error)

Batch modes are all, visible, and metadata. Successful visible no-ops are copied byte-for-byte, keeping the output directory complete. Per-file failures are returned in VideoBatchItem.error; they do not discard successful outputs. The invisible stage is available only as an explicit opt-in in all mode and reuses one loaded VAE runtime across the batch.

Inspect and strip video metadata

Metadata inspection and removal use the same supported video containers:

import remove_ai_watermarks as raiw

report = raiw.inspect_video_metadata("input.mp4")
if report.has_ai_metadata:
    result = raiw.remove_video_metadata("input.mp4")
    if result.remaining:
        raise RuntimeError(f"AI metadata remains: {result.remaining}")

remove_video_metadata does not transcode video or audio streams. Its default output is input_clean.mp4, leaving the source untouched. An explicit output must use the same container extension as the source.

The returned VideoMetadataResult records the source, output, metadata detected before removal, and any markers remaining after the verified strip. MP4/MOV inspection recognizes the native TC260 AIGC entry in moov.udta.meta.keys/ilst; its removal preserves container size and encoded stream bytes. MP4/MOV/M4V are copied in bounded chunks, so a large mdat is not loaded into memory; publication is atomic. MKV/WebM inspection recognizes the corresponding Segment.Tags.Tag.SimpleTag representation; its removal requires ffmpeg for a stream-copy remux. AVI inspection reads LIST/INFO/AIGC, and FLV inspection reads script.onMetaData.AIGC; both use the same verified ffmpeg stream-copy removal path.

Remove video SynthID

Install remove-ai-watermarks[video,diffusion] before using the video SynthID API.

import remove_ai_watermarks as raiw

result = raiw.remove_video_invisible(
    "input.mp4",
    "clean.mp4",
    device="auto",
)
if result.remaining_metadata:
    raise RuntimeError(f"AI metadata remains: {result.remaining_metadata}")

remove_video_invisible supports MP4, MOV, and M4V. It regenerates the complete video through a VAE in bounded batches, shares one seeded latent-noise field across all frames, streams pixels to ffmpeg, copies complete audio, strips source metadata, and publishes atomically. The default output is input_clean.mp4; a distinct same-container output is required.

The returned VideoInvisibleResult includes output geometry, frame rate, frame count, paired PSNR, and the motion-compensated temporal-residual ratio. Those fields measure fidelity and flicker only. They are not a SynthID detector. The default noise_std=0.15 is the current full-clip oracle floor; 0.10 remained detected on the public eight-second Veo calibration carrier. The default profile is oracle-certified. Google does not publish a local decoder for this video payload, so a fresh source-positive, output-negative pair from Gemini's built-in SynthID verifier remains an optional per-file audit. A response inferred from a visible logo or metadata is not such a verdict, and an adversarial follow-up asking ordinary Gemini to reinterpret the verifier is not a second oracle run.

Remove a supported visible video mark

import remove_ai_watermarks as raiw

result = raiw.remove_video_visible(
    "input.mp4",
    "clean.mp4",
    backend="cv2",
    strip_metadata=True,
    temporal_consistency=True,
)
if result.output is None:
    print("No temporally stable supported mark was found")
else:
    print(result.mark)

veo_result = raiw.remove_video_visible(
    "veo.mp4",
    "veo_clean.mp4",
    mark="veo",
)
seedance_result = raiw.remove_video_visible(
    "seedance.mp4",
    "seedance_clean.mp4",
    mark="seedance",
)
dola_result = raiw.remove_video_visible(
    "dola.mp4",
    "dola_clean.mp4",
    mark="dola",
)
hailuo_result = raiw.remove_video_visible(
    "hailuo.mp4",
    "hailuo_clean.mp4",
    mark="hailuo",
)
kling_result = raiw.remove_video_visible(
    "kling.mp4",
    "kling_clean.mp4",
    mark="kling",
)

remove_video_visible scans the complete video before writing output. It combines synthetic multi-scale visual matching with temporal consistency, so an isolated lookalike in one frame is not enough to authorize inpainting. mark="auto" is the default: it evaluates all providers in one decode pass and selects the first stable match in specificity order (sora, veo, seedance, dola, hailuo, kling). Provider confidence values are calibrated independently and are not compared across detectors. Pass one of those explicit values to restrict the scan to a single provider. The Veo detector recognizes the current four-point diamond and the legacy Veo text. Seedance recognizes the boxed AI label, Dola recognizes its compact text label, Hailuo recognizes the composite MINIMAX/Hailuo label, and Kling recognizes its bottom-right logo, wordmark, and version suffix. Each variant has an independent synthetic silhouette and calibrated temporal policy. After each accepted frame is filled, temporal_consistency=True motion-aligns the preceding accepted fill and blends it only when the warped prior mask covers the current mask and a surrounding source-context ring agrees. Scene cuts and disjoint masks keep the independent current fill. Pass temporal_consistency=False for the frame-local baseline.

The returned VideoVisibleResult records the selected mark, the total, detected, and removed frame counts, plus any AI metadata that survived the output encode. The function returns output=None and writes no file when no stable mark is selected. Video pixels are transcoded through ffmpeg while the complete source audio stream is copied. The encoder preserves supported 8-bit source chroma sampling, color tags, MP4/MOV track timescale, and relative variable-frame timestamps. It also retains a non-zero source start PTS and the copied audio offset. A failed encode preserves any existing output; only a completed result is published atomically. SDR 8-bit video is the supported pixel contract. High-bit-depth, PQ, and HLG sources raise RuntimeError before encoding instead of being silently reduced to 8-bit SDR.

Remove invisible watermarks

Install remove-ai-watermarks[qwen-zimage]. Both profiles need it, and both need an NVIDIA GPU.

from pathlib import Path

from remove_ai_watermarks.invisible_engine import InvisibleEngine

engine = InvisibleEngine(
    pipeline="qwen-zimage",  # the default; the only other value is "sdxl-zimage"
    device=None,
    cpu_offload=False,
)

engine.remove_watermark(
    Path("watermarked.png"),
    Path("clean.png"),
)

device=None and device="auto" both run detection. "cuda" pins it without detecting. Every other value raises at construction rather than deferring a guaranteed failure to model-load time.

For limited CUDA memory:

engine = InvisibleEngine(
    pipeline="qwen-zimage",
    cpu_offload=True,
)

Both profiles are CUDA-only, so on a machine without an NVIDIA GPU device=None resolves to cpu and construction raises. For the SDXL global stage instead of Qwen:

engine = InvisibleEngine(pipeline="sdxl-zimage")

The qwen-zimage extra is required for both profiles: each runs the same DiffSynth Z-Image face stage.

remove_watermark takes strength, seed, tiling, resolution, and postprocessing controls. It takes no model id, step count or guidance scale, and neither does the constructor: each profile pins its model stack, its per-stage schedule and CFG 1.0, so passing one raises TypeError at the call rather than being accepted and refused several layers down. Read the method signature in invisible_engine.py or use the CLI guide for the concepts. Defaults can differ between the Python method and CLI profile resolution, so pass values explicitly when reproducibility matters.