SynthID Detector: how to check a video for a watermark today

You can check content for a SynthID mark in two ways named on the Google DeepMind SynthID page: the SynthID Detector portal, which has an early-tester waitlist, and uploading the content in Gemini and asking. The page says Google is working with journalists and media professionals to test the portal.

What SynthID covers per the page

The page lists images and video, audio such as Lyria and NotebookLM podcasts, and recently Gemini text. It describes a watermark that is tested with a detector, not a label a viewer sees.

What it cannot tell you

A detector answers for its own watermark. A clip from another vendor has no reason to carry a SynthID mark, so a negative result is not proof a clip is real. Likewise the Sume docs do not say Sume output is watermarked, so do not expect a hit on a Sume clip.

Practical use

If you publish AI video, a detector check is one input to an evidence file. Pair it with your own job record. See the evidence log pattern and what Sume does and does not add to video.