If you are publishing or subscribing with Chrome, then you can use chrome://webrtc-internals to view details about the stream.

Some documentation links (reference testRTC

• webrtc-internals and getstats parameters – a detailed view of webrtc-internals and the getstats() parameters it collects.
• active connections in webrtc-internals – an explanation of how to find the active connection in webrtc-internals – and how to wrap back from there to find the ICE candidates of the active connection.
• webrtc-internals API trace – a guide on what to expect in the API trace for a successful WebRTC session, along with some typical failure cases.