Hey op, my 2¢: just mute them, everywhere. Duplicate the audio stream, detect ads, use that to mute the volume of whatever is playing the ads.
I am currently working on Sonos / Google Home / Amazon Alexa
Interesting, are you planning to mute Sonos/Home/Alexa by analyzing it's audio output stream? If so: do you plan to use the devices audio controls?
Are you planning on using the Sonos/Home/Alexa microphone for detection of other sources?