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AI image detector by file format

WebM AI video check: what a Matroska file can and cannot show

WebM is a Matroska-based container that isGenAI’s C2PA checker and video metadata viewer do not accept, so a WebM is checked by extracting frames in your browser with the video frame extractor and running the matching-copy check on those frames.

Tool support and container facts as of October 2026. Updated .

Extract frames from the WebMFrequently asked questions
Code-drawn illustration for WebM

Illustration · PNG file

  1. Signature + IHDR
  2. iTXt XML:com.adobe.xmprecord
  3. tEXt parameters
  4. tEXt prompt / workflow
  5. tEXt invokeai_metadata
  6. eXIf
  7. caBX C2PA manifest
  8. IDAT pixels
  9. IEND

AI source type declared

The file labels itself as AI-made.

IPTC DigitalSourceType such as trainedAlgorithmicMedia is read from XMP and shown with its exact value.

Check an image →
AI source type declared: where this record sits inside a PNG file and what the isGenAI report says about it. The picture is a code-drawn illustration.

What WebM holds

WebM restricts Matroska to VP8, VP9 or AV1 video and Vorbis or Opus audio. Matroska has tag elements for titles and dates, but mainstream AI video tools export MP4 or MOV, and the C2PA specification’s video support centres on ISO base media containers. A WebM is very often a transcode made for the web, which means its origin records live in an earlier file.

Browser screen recorders also produce WebM, which explains many AI clips in this format.

What isGenAI reads from a WebM

The video frame extractor decodes WebM in your browser, up to 200 MiB and ten minutes, and exports PNG stills with a manifest of the timestamps requested. Upload a still to the AI image detector: it will carry no file records, which is expected, but its hash and perceptual fingerprint are compared with known copies. The C2PA checker and video metadata viewer accept MP4 and MOV, not WebM.

Nothing about the pixels is scored; the value is in matching and comparison.

Advice

Ask for the MP4 or MOV the WebM was made from and check that in the C2PA checker. If the WebM is a screen recording of a generator’s preview, the generator’s own export is the file with records.

Compare frames with the image pixel compare tool to link a WebM to a known original.

How to check a file in this format

  1. Keep the original bytes. Do not open and re-save the file in an editor before checking it.
  2. Use the tool that accepts the format: the AI image detector for PNG, JPEG, WebP, AVIF and TIFF; the C2PA checker for those plus HEIC, PDF, MP4 and MOV.
  3. Read each finding with its source field. The report names the container record it came from.
  4. If you must convert, convert a copy and compare both files with the image metadata compare tool so you know what the conversion dropped.

Extract frames from the WebM

Frequently asked questions

Does isGenAI accept WebM?

The video frame extractor does, in your browser. The C2PA checker and video metadata viewer accept MP4 and MOV only.

Can a WebM carry C2PA Content Credentials?

The C2PA specification’s video embedding targets ISO base media containers such as MP4 and MOV; isGenAI does not read credentials from WebM.

How do I check an AI WebM clip?

Extract frames, run the matching-copy check on a frame, and trace the original MP4 or MOV for the signed record.

Why is my AI clip a WebM at all?

Browser recorders and web transcodes produce WebM. The generator’s own export, usually MP4, is where any provenance would be.

Sources

Container facts come from the published specifications. Tool support describes isGenAI as deployed in October 2026.