I know of traditional media ad-tech that uses ultrasound markers embedded in ads to track/verify if the ads were really broadcast as promised (number of times & in the correct time slots.

So the steps are:

1. Inject ultrasound markers into ad during post-production.

2. Have a server with multiple tuner cards to monitor multiple stations, grab the audio.

3. Filter audio on specific ultrasound frequencies, search for the pre-injected patterns.

4. Generate reports.

5. Get paid.