SynthID

How does SynthID work?

SynthID uses two deep learning models — one for watermarking and another for identifying:

• Watermarking: SynthID uses an embedded watermarking technology that adds a digital watermark directly into AI-generated content. The combined model is optimized to improve imperceptibility by aligning the watermark to the original content.
• Identification: SynthID can scan the image or audio for its digital watermark and help users assess whether the content, or part of it, was generated using our AI models.

SynthID for AI-generated music

In November 2023, SynthID was expanded to watermark and identify AI-generated music and audio. SynthID's first deployment will be through Lyria, our most advanced AI music generation model to date. SynthID will watermark any content published by our Lyria model.

SynthID’s watermark is embedded directly into the audio waveform of AI-generated audio.

First, SynthID converts the audio wave, a one dimensional representation of sound into a spectrogram. A spectrogram is a two dimensional visualisation that shows how the spectrum of frequencies in a sound evolves over time. Once the spectrogram is computed, the digital watermark is added into it. Finally, the spectrogram is converted back to the waveform. During this conversion step, SynthID leverages audio properties to ensure that the watermark is inaudible to the human ear so that it doesn’t compromise the listening experience.

The watermark is robust to many common modifications such as noise additions, MP3 compression, or speeding up and slowing down the track. SynthID can scan the audio track to detect the presence of the watermark at different points to help determine if parts of it may have been generated by Lyria.

SynthID for AI-generated images

To help identify AI-generated images, SynthID is available for Vertex AI customers using the Imagen suite of our latest text-to-image models that use input text to create photorealistic images.

SynthID adds a digital watermark directly into the pixels of AI-generated images, making it imperceptible to the human eye.

We designed SynthID so it doesn’t compromise image quality, and allows the watermark to remain detectable, even after modifications like adding filters, changing colours, and saving with various lossy compression schemes — most commonly used for JPEGs.

SynthID can scan the image for a digital watermark and provides three confidence levels for interpreting the results for identification. If a digital watermark is detected, part of the image is likely generated by Imagen.