I'm considering doing some ML stuff for a mobile DJ app.. like beat/bpm detection, instrument / vocal separation etc. Have you seen anything recent that might be efficient enough to run on a mobile device and process a track in a reasonable amount of time ( less than song length ) ?
Made a simple and free pushup counter app that uses the depth sensor on the iPhone to count push ups. https://PushupCounterApp.com The existing apps I tried were subscription based / unreliable / overcomplicated. It's a WIP since I hacked it together over a few days.