Apparently it uses some special directional mic from Soundskrit. Product page for the chip: https://soundskrit.ca/technology/
The patent: https://patentimages.storage.googleapis.com/94/2b/ff/984fa6f...
PR about the partnership: https://www.prnewswire.com/news-releases/opal-launches-tadpo...
> A first on any consumer device, Tadpole's trademarked directional VisiMic™ microphone only captures audio that the camera can see. VisiMic is made in partnership with Soundskrit, the Quebec-based audio firm that specializes in cutting-edge directional microphone technology.