fix(webrtc): Fix Firefox simulcast race condition and respect HPB bandwidth limits

src/utils/signaling.js

@@ -1282,6 +1282,12 @@ Signaling.Standalone.prototype.joinCall = function(token, flags, silent, recordi
 Signaling.Standalone.prototype.joinResponseReceived = function(data, token) {
 	console.debug('Joined', data, token)
 	this.signalingRoomJoined = token
+	if (data.room && data.room.bandwidth && data.room.bandwidth.maxstreambitrate) {
+		const totalBps = data.room.bandwidth.maxstreambitrate
+		if (typeof totalBps === 'number' && totalBps > 0) {
+			this.maxStreamBits = totalBps
+		}
+	}
 	if (this.pendingJoinCall && token === this.pendingJoinCall.token) {
 		const pendingJoinCallResolve = this.pendingJoinCall.resolve
 		const pendingJoinCallReject = this.pendingJoinCall.reject

src/utils/webrtc/simplewebrtc/peer.js

@@ -356,69 +356,94 @@ function mungeSdpForSimulcasting(sdp) {
 }
 /* eslint-enable */
 
+Peer.prototype._getMaxBitrates = function() {
+	const connection = this.parent ? this.parent.config.connection : null
+	if (connection && connection.maxStreamBits) {
+		const partValue = Math.floor(connection.maxStreamBits / 21 / 100) * 100
+		return {
+			high: partValue * 16,
+			medium: partValue * 4,
+			low: partValue,
+		}
+	}
+	return this.maxBitrates
+}
+
+Peer.prototype._createOffer = function(options, sendVideo) {
+	const self = this
+	this.pc.createOffer(options).then(function(offer) {
+		if (sendVideo && self.enableSimulcast) {
+			// This SDP munging only works with Chrome (Safari STP may support it too)
+			if (adapter.browserDetails.browser === 'chrome' || adapter.browserDetails.browser === 'safari') {
+				console.debug('Enabling Simulcasting for Chrome (SDP munging)')
+				offer.sdp = mungeSdpForSimulcasting(offer.sdp)
+			} else if (adapter.browserDetails.browser !== 'firefox') {
+				console.debug('Simulcast can only be enabled on Chrome or Firefox')
+			}
+		}
+
+		self.pc.setLocalDescription(offer).then(function() {
+			if (self.parent.config.nick) {
+				// The offer is a RTCSessionDescription that only serializes
+				// its own attributes to JSON, so if extra attributes are needed
+				// a regular object has to be sent instead.
+				offer = {
+					type: offer.type,
+					sdp: offer.sdp,
+					nick: self.parent.config.nick,
+				}
+			}
+			self.send('offer', offer)
+		}).catch(function(error) {
+			console.warn('setLocalDescription for offer failed: ', error)
+		})
+	}).catch(function(error) {
+		console.warn('createOffer failed: ', error)
+	})
+}
+
 Peer.prototype.offer = function(options) {
 	const sendVideo = this.sendVideoIfAvailable && this.type !== 'screen'
 	if (sendVideo && this.enableSimulcast && adapter.browserDetails.browser === 'firefox') {
 		console.debug('Enabling Simulcasting for Firefox (RID)')
 		const sender = this.pc.getSenders().find(function(s) {
-			return s.track.kind === 'video'
+			return s.track && s.track.kind === 'video'
 		})
 		if (sender) {
 			let parameters = sender.getParameters()
 			if (!parameters) {
 				parameters = {}
 			}
+			const maxBitrates = this._getMaxBitrates()
 			parameters.encodings = [
 				{
 					rid: 'h',
 					active: true,
-					maxBitrate: this.maxBitrates.high,
+					maxBitrate: maxBitrates.high,
 				},
 				{
 					rid: 'm',
 					active: true,
-					maxBitrate: this.maxBitrates.medium,
+					maxBitrate: maxBitrates.medium,
 					scaleResolutionDownBy: 2,
 				},
 				{
 					rid: 'l',
 					active: true,
-					maxBitrate: this.maxBitrates.low,
+					maxBitrate: maxBitrates.low,
 					scaleResolutionDownBy: 4,
 				},
 			]
-			sender.setParameters(parameters)
+			sender.setParameters(parameters).then(function() {
+				this._createOffer(options, sendVideo)
+			}.bind(this)).catch(function(error) {
+				console.warn('Failed to set simulcast parameters in Firefox, creating offer anyway', error)
+				this._createOffer(options, sendVideo)
+			}.bind(this))
+			return
 		}
 	}
-	this.pc.createOffer(options).then(function(offer) {
-		if (sendVideo && this.enableSimulcast) {
-			// This SDP munging only works with Chrome (Safari STP may support it too)
-			if (adapter.browserDetails.browser === 'chrome' || adapter.browserDetails.browser === 'safari') {
-				console.debug('Enabling Simulcasting for Chrome (SDP munging)')
-				offer.sdp = mungeSdpForSimulcasting(offer.sdp)
-			} else if (adapter.browserDetails.browser !== 'firefox') {
-				console.debug('Simulcast can only be enabled on Chrome or Firefox')
-			}
-		}
-
-		this.pc.setLocalDescription(offer).then(function() {
-			if (this.parent.config.nick) {
-				// The offer is a RTCSessionDescription that only serializes
-				// its own attributes to JSON, so if extra attributes are needed
-				// a regular object has to be sent instead.
-				offer = {
-					type: offer.type,
-					sdp: offer.sdp,
-					nick: this.parent.config.nick,
-				}
-			}
-			this.send('offer', offer)
-		}.bind(this)).catch(function(error) {
-			console.warn('setLocalDescription for offer failed: ', error)
-		})
-	}.bind(this)).catch(function(error) {
-		console.warn('createOffer failed: ', error)
-	})
+	this._createOffer(options, sendVideo)
 }
 
 Peer.prototype.handleOffer = function(offer) {