https://recordrtc.org/
RecordRTC: Home
RecordRTC is a server-less (entire client-side) JavaScript library can be used to record WebRTC audio/video media streams. It supports cross-browser...
https://www.webrtc-experiment.com/RecordRTC/simple-demos/auto-stop-on-silence.html
Auto Stop RecordRTC on Silence
autostopsilence