How the video check works
- 1
Content Credentials in the container
MP4 and MOV files can carry a C2PA manifest in a dedicated box. Sora writes one; so do Adobe tools and some cameras. We read it in your browser.
- 2
Encoder and camera tags
Phones record their make, model and software in the file. Generators and editors often leave their own encoder name. Re-encoded downloads usually carry neither.
- 3
Four frames, compared
We take four frames from evenly spaced points and inspect them side by side: faces and objects that change identity, limbs that morph, text that melts and motion that defies physics.
- 4
A verdict with its evidence
Content Credentials confirm it outright. Otherwise the frames and file data are weighed together, and the verdict comes with a confidence level and everything it found.
What AI video generators leave behind
Downloading from TikTok, Instagram or X re-encodes the video and strips its metadata, and visible watermarks are easy to crop. A clean file proves nothing either way.
Signs a video was made with AI
- Faces, clothes or tattoos that change between shots of the same person
- Hands and props that merge, multiply or pass through each other
- Text on signs and screens that shifts or reads as nonsense
- Background people who walk in loops or melt into the scenery
- A floating, too-smooth camera with no shake, even when handheld
- Shadows and reflections that do not follow the action
- Clips that are exactly 5, 8 or 10 seconds long with no natural cut
Why Gireta catches what single-model detectors miss
Most detectors run one classifier over the pixels and hand back a score. Gireta starts where the proof is: the signatures AI tools embed in their own files. When ChatGPT, Gemini, Firefly, Sora or Stable Diffusion have labelled an image, Gireta reads that label, confirms the verdict and names the tool.
When the labels have been stripped, four more layers run: generator fingerprints in the file, camera data, a close visual inspection of hands, text, light and texture, and forensic views of the pixels. The verdict comes with the evidence behind it, so you can show your work.
And it all runs in your browser, so you can check sensitive images without uploading them anywhere.
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Questions
How can you tell if a video is AI-generated?
Check for Content Credentials first: Sora writes them into the file, and Gireta reads them in a second. Then look across frames for faces and objects that change, text that melts and physics that fails. Google's SynthID Detector reads the watermark in Veo videos.
Can it detect Sora videos?
Yes, when the file still carries its C2PA manifest. Re-uploaded copies lose it, so the visual check carries the result, and the moving Sora watermark is a strong clue when it has not been cropped.
Is the Gireta AI video detector free?
Yes, with no sign-up. The visual check is rate limited per visitor to keep it free.
Do you upload my video?
No. The file is read in your browser. Only four small frames are sent for the visual check, then discarded.
How long can the video be?
Any length. We read the metadata at the start and end of the file and take four frames, so long files are checked as quickly as short ones.
Can it detect deepfakes?
It catches fully generated video and the frame-to-frame glitches generators leave behind, such as faces and objects that change identity between frames.
Sources
- OpenAI: C2PA and watermarks in Sora
- C2PA: embedding manifests in MP4 and MOV (BMFF)
- Google: SynthID Detector
Last updated October 19, 2026.