RTCInboundRtpStreamStats.packetsDuplicated - Web APIs
you can get a more accurate tally of how many packets have been lost on the stream by adding packetsduplicated to packetslost.

RTCRtpReceiver.getStats() - Web APIs
receiver.getstats().then(function(stats) { document.getelementbyid("lostpackets").innertext = stats.packetslost; }); specifications specification status comment webrtc 1.0: real-time communication between browsersthe definition of 'rtcrtpreceiver.getstats()' in that specification.