There are 3 repositories under data-over-audio topic.
Transmit data using ultrasonic audio. Perfect for offline/network-free data transfer, automatic content recognition (ACR), and broadcast.
SoniControl - the first ultrasonic firewall
Allows your device to communicate in an electronic sound language. Follow us on twitter: https://twitter.com/qrtone. Demo App in https://universite-gustave-eiffel.github.io/qrtone/
C Libraries to encode and decode data over sound
Data transmission over audio
iPhone SDK to decode ultrasonics
Implementing chirp.io SDK in Android