Plivo analyses the network and audio stream in real-time throughout the course of the call and emits JS events when degradation is detected. 

Refer to the MediaMetrics section on the Browser SDK documentation for a complete list of events generated by the SDK wrt call quality. 

Check out the Implementing MediaMetrics section of our example app on Github to learn more about handling these events in your web application.

Media Metrics is also supported on Plivo iOS and Android SDKs.