What Is a SynthID Watermark? Images, Text, Audio & Video

SynthID is a watermarking technology from Google DeepMind designed to mark AI-generated content so it can later be identified. It covers images, video, audio, and text in DeepMind’s documentation. It is not a single public detector that every company shares, and it is not the same thing as C2PA Content Credentials. AI Watermark Center does not independently detect SynthID — verification stays with provider tools where they exist.

Modalities

Google DeepMind documents SynthID watermarks in images, video, audio, and text. Image and video watermarks are described as invisible signals added when content is created. Audio watermarks are described as inaudible. Text watermarking adjusts the choice among plausible next tokens rather than inserting hidden characters.

Imperceptible signals

The documented design goal is that people should not notice the mark, and that quality should not be obviously degraded. That does not mean the mark is unbreakable, or that a third party can read it without the matching detector.

Detection differs by media

Gemini Apps currently offer user-facing verification for supported images, video, and audio. Google DeepMind also documents identification of Gemini-generated text. Those surfaces are not interchangeable. AI Watermark Center’s Unicode scanner does not detect SynthID, and the image inspector’s C2PA check is not a SynthID result.

Provider examples

Google documents SynthID across Gemini text and media, including Nano Banana image outputs — see the Gemini SynthID page. OpenAI documents SynthID on supported generated images and audio — see the OpenAI SynthID page. Both provider pages, the database, and the compare view own product behaviour; this guide stays technology-level.

Public detection availability differs

• Gemini’s verifier currently identifies Google AI SynthID, not every company that may adopt SynthID.
• OpenAI publishes a verifier and API for supported OpenAI image and audio signals.
• Claude’s statistical text detector is announced, not integrated here.
• AI Watermark Center does not detect SynthID.

Related pages

• Gemini SynthID — Google product documentation and verification surfaces.
• OpenAI SynthID — image and audio scope OpenAI currently documents.
• C2PA vs SynthID — metadata provenance versus invisible watermarks.
• AI watermark detector — what can actually be checked locally.
• AI Watermark Database — dated provider claim records.