Apple have this built into their OS (https://developer.apple.com/documentation/mediaaccessibility/responding-to-changes-in-the-flashing-lights-setting https://d

Apple have this built into their OS (https://developer.apple.com/documentation/mediaaccessibility/responding-to-changes-in-the-flashing-lights-setting https://developer.apple.com/documentation/mediaaccessibility...) and publish the implementation (https://github.com/apple/VideoFlashingReduction https://github.com/apple/VideoFlashingReduction) There are a few other implementations out there but this is about as low latency as I’ve found, and takes into account several factors.