Fix lost audio track on safari

Signed-off-by: Marcel Müller <marcel-mueller@gmx.de>

src/utils/webrtc/simplewebrtc/peer.js

@@ -3,6 +3,7 @@ import util from 'util'
 import adapter from 'webrtc-adapter'
 import webrtcSupport from 'webrtcsupport'
 import WildEmitter from 'wildemitter'
+import UAParser from 'ua-parser-js'
 
 /**
  * @param {object} stream the stream object.
@@ -42,6 +43,10 @@ function Peer(options) {
 	this._processPendingReplaceTracksPromise = null
 	this._initialStreamSetup = false
 	this.sid = options.sid || Date.now().toString()
+
+	const browserName = (new UAParser()).getBrowser().name
+	this.isSafari = browserName === 'Safari' || browserName === 'Mobile Safari'
+
 	this.pc = new RTCPeerConnection(this.parent.config.peerConnectionConfig)
 	this.pc.addEventListener('icecandidate', this.onIceCandidate.bind(this))
 	this.pc.addEventListener('endofcandidates', function(event) {
@@ -831,7 +836,10 @@ Peer.prototype._replaceTrack = async function(newTrack, oldTrack, stream) {
 			return
 		}
 
-		if (sender.track && newTrack && !newTrack.enabled) {
+		// When replacing with a null track on Safari the reference to the track is
+		// lost (setting trackDisabled is not enough). Therefore we keep the track
+		// intact and don't replace it with a null track.
+		if (sender.track && newTrack && !newTrack.enabled && !this.isSafari) {
 			// Replace with a null track to stop the sender.
 			newTrack = null
 		}
@@ -871,6 +879,8 @@ Peer.prototype.handleSentTrackEnabledChanged = function(track, stream) {
 		this.handleSentTrackReplacedBound(track, track, stream)
 	} else if (!track.enabled && sender) {
 		this.handleSentTrackReplacedBound(track, track, stream)
+	} else if (!sender && !stoppedSender) {
+		console.error('No sender found to handle localTrackEnabledChanged', track, stream)
 	}
 }