diff --git a/lib/call.js b/lib/call.js
index 68c8cef..6582a8b 100644
--- a/lib/call.js
+++ b/lib/call.js
@@ -1,421 +1,423 @@
 'use strict';
 
 import debug from 'debug';
 import uuidv4 from 'uuid/v4';
 import utils from './utils';
 
 import { EventEmitter } from 'events';
 
 const DEBUG = debug('sylkrtc:Call');
 
 
 class Call extends EventEmitter {
     constructor(account) {
         super();
         this._account = account;
         this._id = null;
         this._direction = null;
         this._pc = null;
         this._state = null;
         this._terminated = false;
         this._incomingSdp = null;
         this._localIdentity = new utils.Identity(account.id, account.displayName);
         this._remoteIdentity = null;
         this._remoteStreams = new MediaStream();
         this._localStreams = new MediaStream();
         this._dtmfSender = null;
         this._delay_established = false;  // set to true when we need to delay posting the state change to 'established'
         this._setup_in_progress = false;  // set while we set the remote description and setup the peer copnnection
 
         // bind some handlers to this instance
         this._onDtmf = this._onDtmf.bind(this);
     }
 
     get account() {
         return this._account;
     }
 
     get id() {
         return this._id;
     }
 
     get direction() {
         return this._direction;
     }
 
     get state() {
         return this._state;
     }
 
     get localIdentity() {
         return this._localIdentity;
     }
 
     get remoteIdentity() {
         return this._remoteIdentity;
     }
 
     getLocalStreams() {
         if (this._pc !== null) {
             if (this._pc.getSenders) {
                 this._pc.getSenders().forEach((e) => {
                     this._localStreams.addTrack(e.track);
                 });
                 return [this._localStreams];
             } else {
                 return this._pc.getLocalStreams();
             }
         } else {
             return [];
         }
     }
 
     getRemoteStreams() {
         if (this._pc !== null) {
            if (this._pc.getReceivers) {
               this._pc.getReceivers().forEach((e) => {
                   this._remoteStreams.addTrack(e.track);
               });
               return [this._remoteStreams];
           } else {
                 return this._pc.getRemoteStreams();
           }
         } else {
             return [];
         }
     }
 
     getSenders() {
         if (this._pc !== null) {
            return this._pc.getSenders();
         } else {
             return [];
         }
     }
 
     getReceivers() {
         if (this._pc !== null) {
            return this._pc.getReceivers();
         } else {
             return [];
         }
     }
 
     answer(options = {}) {
         if (this._state !== 'incoming') {
             throw new Error('Call is not in the incoming state: ' + this._state);
         }
 
         if (!options.localStream) {
             throw new Error('Missing localStream');
         }
 
         const pcConfig = options.pcConfig || {iceServers:[]};
         const answerOptions = options.answerOptions;
 
         // Create the RTCPeerConnection
         this._initRTCPeerConnection(pcConfig);
 
         this._pc.addStream(options.localStream);
         this.emit('localStreamAdded', options.localStream);
         this._pc.setRemoteDescription(
             new RTCSessionDescription({type: 'offer', sdp: this._incomingSdp}),
             // success
             () => {
                 utils.createLocalSdp(this._pc, 'answer', answerOptions)
                     .then((sdp) => {
                         DEBUG('Local SDP: %s', sdp);
                         this._sendAnswer(sdp);
                     })
                     .catch((reason) => {
                         DEBUG(reason);
                         this.terminate();
                     });
             },
             // failure
             (error) => {
                 DEBUG('Error setting remote description: %s', error);
                 this.terminate();
             }
         );
     }
 
     terminate() {
         if (this._terminated) {
             return;
         }
         DEBUG('Terminating call');
         this._sendTerminate();
     }
 
     sendDtmf(tones, duration=100, interToneGap=70) {
         DEBUG('sendDtmf()');
         if (this._dtmfSender === null) {
             if (this._pc !== null) {
                 let track = null;
                 try {
                     track = this._pc.getLocalStreams()[0].getAudioTracks()[0];
                 } catch (e) {
                     // ignore
                 }
                 if (track !== null) {
                     DEBUG('Creating DTMF sender');
                     this._dtmfSender = this._pc.createDTMFSender(track);
                     if (this._dtmfSender) {
                         this._dtmfSender.addEventListener('tonechange', this._onDtmf);
                     }
                 }
             }
         }
         if (this._dtmfSender) {
             DEBUG('Sending DTMF tones');
             this._dtmfSender.insertDTMF(tones, duration, interToneGap);
         }
     }
 
     // Private API
 
     _initOutgoing(uri, options={}) {
         if (uri.indexOf('@') === -1) {
             throw new Error('Invalid URI');
         }
 
         if (!options.localStream) {
             throw new Error('Missing localStream');
         }
 
         this._id = uuidv4();
         this._direction = 'outgoing';
         this._remoteIdentity = new utils.Identity(uri);
 
         const pcConfig = options.pcConfig || {iceServers:[]};
         const offerOptions = options.offerOptions;
 
         // Create the RTCPeerConnection
         this._initRTCPeerConnection(pcConfig);
 
         this._pc.addStream(options.localStream);
         this.emit('localStreamAdded', options.localStream);
         utils.createLocalSdp(this._pc, 'offer', offerOptions)
             .then((sdp) => {
                 DEBUG('Local SDP: %s', sdp);
                 this._sendCall(uri, sdp);
             })
             .catch((reason) => {
                 DEBUG(reason);
                 this._localTerminate(reason);
             });
     }
 
     _initIncoming(id, caller, sdp) {
         this._id = id;
         this._remoteIdentity = new utils.Identity(caller.uri, caller.display_name);
         this._incomingSdp = sdp;
         this._direction = 'incoming';
         this._state = 'incoming';
         DEBUG('Remote SDP: %s', sdp);
     }
 
     _handleEvent(message) {
         DEBUG('Call event: %o', message);
         switch (message.event) {
             case 'state':
                 let oldState = this._state;
                 let newState = message.state;
                 this._state = newState;
 
                 if (newState === 'accepted' && this._direction === 'outgoing') {
                     DEBUG('Call accepted');
                     this.emit('stateChanged', oldState, newState, {});
                     const sdp = utils.mungeSdp(message.sdp);
                     DEBUG('Remote SDP: %s', sdp);
                     this._setup_in_progress = true;
                     this._pc.setRemoteDescription(
                         new RTCSessionDescription({type: 'answer', sdp: sdp}),
                         // success
                         () => {
                             this._setup_in_progress = false;
                             if (!this._terminated) {
                                 if (this._delay_established) {
                                     oldState = this._state;
                                     this._state = 'established';
                                     DEBUG('Setting delayed established state!');
                                     this.emit('stateChanged', oldState, this._state, {});
                                     this._delay_established = false;
                                 }
                             }
                         },
                         // failure
                         (error) => {
                             DEBUG('Error accepting call: %s', error);
                             this.terminate();
                         }
                     );
                 } else if (newState === 'established' && this._direction === 'outgoing') {
                     if (this._setup_in_progress) {
                         this._delay_established = true;
                     } else {
                         this.emit('stateChanged', oldState, newState, {});
                     }
                 } else if (newState === 'terminated') {
                     this.emit('stateChanged', oldState, newState, {reason: message.reason});
                     this._terminated = true;
                     this._account._calls.delete(this.id);
                     this._closeRTCPeerConnection();
                 } else {
                     this.emit('stateChanged', oldState, newState, {});
                 }
                 break;
             default:
                 break;
         }
     }
 
     _initRTCPeerConnection(pcConfig) {
         if (this._pc !== null) {
             throw new Error('RTCPeerConnection already initialized');
         }
 
         this._pc = new RTCPeerConnection(pcConfig);
         this._pc.addEventListener('addstream', (event) => {
             DEBUG('Stream added');
             this.emit('streamAdded', event.stream);
         });
         this._pc.addEventListener('icecandidate', (event) => {
             if (event.candidate !== null) {
                 DEBUG('New ICE candidate %o', event.candidate);
             } else {
                 DEBUG('ICE candidate gathering finished');
             }
             this._sendTrickle(event.candidate);
         });
     }
 
     _sendRequest(req, cb) {
         this._account._sendRequest(req, cb);
     }
 
     _sendCall(uri, sdp) {
         const req = {
             sylkrtc: 'session-create',
             account: this.account.id,
             session: this.id,
             uri: uri,
             sdp: sdp
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Call error: %s', error);
                 this._localTerminate(error);
             }
         });
     }
 
     _sendTerminate() {
         const req = {
             sylkrtc: 'session-terminate',
             session: this.id
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Error terminating call: %s', error);
                 this._localTerminate(error);
             }
         });
         setTimeout(() => {
             if (!this._terminated) {
                 DEBUG('Timeout terminating call');
                 this._localTerminate('200 OK');
             }
             this._terminated = true;
         }, 150);
     }
 
     _sendTrickle(candidate) {
         const req = {
             sylkrtc: 'session-trickle',
             session: this.id,
             candidates: candidate !== null ? [candidate] : [],
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Trickle error: %s', error);
                 this._localTerminate(error);
             }
         });
     }
 
     _sendAnswer(sdp) {
         const req = {
             sylkrtc: 'session-answer',
             session: this.id,
             sdp: sdp
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Answer error: %s', error);
                 this.terminate();
             }
         });
     }
 
     _closeRTCPeerConnection() {
         DEBUG('Closing RTCPeerConnection');
         if (this._pc !== null) {
             let tempStream;
             if (this._pc.getSenders) {
-                tempStream = new MediaStream();
+                let tracks = [];
                 for (let track of this._pc.getSenders()) {
-                    tempStream.addTrack(track.track);
+                    tracks = tracks.concat(track.track);
                 }
+                tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getLocalStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
 
             if (this._pc.getReceivers) {
-                tempStream = new MediaStream();
+                let tracks = [];
                 for (let track of this._pc.getReceivers()) {
-                    tempStream.addTrack(track.track);
+                    tracks = tracks.concat(track.track);
                 }
+                tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getRemoteStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
             this._pc.close();
             this._pc = null;
             if (this._dtmfSender !== null) {
                 this._dtmfSender.removeEventListener('tonechange', this._onDtmf);
                 this._dtmfSender = null;
             }
         }
     }
 
     _localTerminate(error) {
         if (this._terminated) {
             return;
         }
         DEBUG('Local terminate');
         this._account._calls.delete(this.id);
         this._terminated = true;
         const oldState = this._state;
         const newState = 'terminated';
         const data = {
             reason: error.toString()
         };
         this._closeRTCPeerConnection();
         this.emit('stateChanged', oldState, newState, data);
     }
 
     _onDtmf(event) {
         DEBUG('Sent DTMF tone %s', event.tone);
         this.emit('dtmfToneSent', event.tone);
     }
 }
 
 
 export { Call };
diff --git a/lib/conference.js b/lib/conference.js
index 3edc869..3901eb7 100644
--- a/lib/conference.js
+++ b/lib/conference.js
@@ -1,716 +1,720 @@
 'use strict';
 
 import debug from 'debug';
 import uuidv4 from 'uuid/v4';
 import utils from './utils';
 
 import { EventEmitter } from 'events';
 
 const DEBUG = debug('sylkrtc:Conference');
 
 
 class Participant extends EventEmitter {
     constructor(publisherId, identity, conference) {
         super();
         this._id = uuidv4();
         this._publisherId = publisherId;
         this._identity = identity;
         this._conference = conference;
         this._state = null;
         this._pc = null;
         this._stream = new MediaStream();
         this._videoSubscriptionPaused = false;
         this._audioSubscriptionPaused = false;
         this._videoPublishingPaused = false;
         this._audioPublishingPaused = false;
     }
 
     get id() {
         return this._id;
     }
 
     get publisherId() {
         return this._publisherId;
     }
 
     get identity() {
         return this._identity;
     }
 
     get conference() {
         return this._conference;
     }
 
     get videoPaused() {
         return this._videoSubscriptionPaused;
     }
 
     get state() {
         return this._state;
     }
 
     getReceivers() {
         if (this._pc !== null) {
            return this._pc.getReceivers();
         } else {
             return [];
         }
     }
 
     get streams() {
         if (this._pc !== null) {
             if (this._pc.getReceivers) {
                 this._pc.getReceivers().forEach((e) => {
                     this._stream.addTrack(e.track);
                 });
                 return [this._stream];
             } else {
                 return this._pc.getRemoteStreams();
             }
         } else {
             return [];
         }
     }
 
 
     attach() {
         if (this._state !== null) {
             return;
         }
         this._setState('progress');
         this._sendAttach();
     }
 
     detach(isRemoved=false) {
         if (this._state !== null) {
             if (!isRemoved) {
                 this._sendDetach();
             } else {
                 this._close();
             }
         }
     }
 
     pauseVideo() {
         this._sendUpdate({video: false});
         this._videoSubscriptionPaused = true;
     }
 
     resumeVideo() {
         this._sendUpdate({video: true});
         this._videoSubscriptionPaused = false;
     }
 
     _setState(newState) {
         const oldState = this._state;
         this._state = newState;
         DEBUG(`Participant ${this.id} state change: ${oldState} -> ${newState}`);
         this.emit('stateChanged', oldState, newState);
     }
 
     _handleOffer(offerSdp) {
         DEBUG('Handling SDP for participant offer: %s', offerSdp);
 
         // Create the RTCPeerConnection
         const pcConfig = this.conference._pcConfig;
         const pc = new RTCPeerConnection(pcConfig);
         pc.addEventListener('addstream', (event) => {
             DEBUG('Stream added');
             this.emit('streamAdded', event.stream);
         });
         pc.addEventListener('icecandidate', (event) => {
             if (event.candidate !== null) {
                 DEBUG('New ICE candidate %o', event.candidate);
             } else {
                 DEBUG('ICE candidate gathering finished');
             }
             this._sendTrickle(event.candidate);
         });
         this._pc = pc;
 
         // no need for a local stream since we are only going to receive media here
         pc.setRemoteDescription(
             new RTCSessionDescription({type: 'offer', sdp: offerSdp}),
             // success
             () => {
                 utils.createLocalSdp(pc, 'answer')
                     .then((sdp) => {
                         DEBUG('Local SDP: %s', sdp);
                         this._sendAnswer(sdp);
                     })
                     .catch((reason) => {
                         DEBUG(reason);
                         this._close();
                     });
             },
             // failure
             (error) => {
                 DEBUG('Error setting remote description: %s', error);
                 this._close();
             }
         );
     }
 
     _sendAttach() {
         const req = {
             sylkrtc: 'videoroom-feed-attach',
             session: this.conference.id,
             publisher: this._publisherId,
             feed: this.id
         };
         DEBUG('Sending request: %o', req);
         this.conference._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Error attaching to participant %s: %s', this._publisherId, error);
             }
         });
     }
 
     _sendDetach() {
         const req = {
             sylkrtc: 'videoroom-feed-detach',
             session: this.conference.id,
             feed: this.id
         };
         DEBUG('Sending request: %o', req);
         this.conference._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Error detaching to participant %s: %s', this._publisherId, error);
             }
             this._close();
         });
     }
 
     _sendTrickle(candidate) {
         const req = {
             sylkrtc: 'videoroom-session-trickle',
             session: this.id,
             candidates: candidate !== null ? [candidate] : []
         };
         this.conference._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Trickle error: %s', error);
                 this._close();
             }
         });
     }
 
     _sendAnswer(sdp) {
         const req = {
             sylkrtc: 'videoroom-feed-answer',
             session: this.conference.id,
             feed: this.id,
             sdp: sdp
         };
         DEBUG('Sending request: %o', req);
         this.conference._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Answer error: %s', error);
                 this._close();
             }
         });
     }
 
     _sendUpdate(options = {}) {
         const req = {
             sylkrtc: 'videoroom-session-update',
             session: this.id,
             options: options
         };
         DEBUG('Sending update participant request %o', req);
         this.conference._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Answer error: %s', error);
             }
         });
     }
 
     _close() {
         DEBUG('Closing Participant RTCPeerConnection');
         if (this._pc !== null) {
             let tempStream;
             if (this._pc.getSenders) {
-                tempStream = new MediaStream();
+                let tracks = [];
                 for (let track of this._pc.getSenders()) {
-                    tempStream.addTrack(track.track);
+                    tracks = tracks.concat(track.track);
                 }
+                tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getLocalStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
 
             if (this._pc.getReceivers) {
-                tempStream = new MediaStream();
+                let tracks = [];
                 for (let track of this._pc.getReceivers()) {
-                    tempStream.addTrack(track.track);
+                    tracks = tracks.concat(track.track);
                 }
+                tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getRemoteStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
             this._pc.close();
             this._pc = null;
             this._setState(null);
         }
     }
 }
 
 
 class ConferenceCall extends EventEmitter {
     constructor(account) {
         super();
         this._account = account;
         this._id = null;
         this._pc = null;
         this._participants = new Map();
         this._terminated = false;
         this._state = null;
         this._localIdentity = new utils.Identity(account.id, account.displayName);
         this._localStreams = new MediaStream();
         this._remoteIdentity = null;
         this._activeParticpants = [];
         this._pcConfig = null;  // saved on initialize, used later for subscriptions
         this._delay_established = false;  // set to true when we need to delay posting the state change to 'established'
         this._setup_in_progress = false;  // set while we set the remote description and setup the peer copnnection
     }
 
     get account() {
         return this._account;
     }
 
     get id() {
         return this._id;
     }
 
     get direction() {
         // make this object API compatible with `Call`
         return 'outgoing';
     }
 
     get state() {
         return this._state;
     }
 
     get localIdentity() {
         return this._localIdentity;
     }
 
     get remoteIdentity() {
         return this._remoteIdentity;
     }
 
     get participants() {
         return Array.from(new Set(this._participants.values()));
     }
 
     get activeParticipants() {
         return this._activeParticpants;
     }
 
     getLocalStreams() {
         if (this._pc !== null) {
             if (this._pc.getSenders) {
                 this._pc.getSenders().forEach((e) => {
                     this._localStreams.addTrack(e.track);
                 });
                 return [this._localStreams];
             } else {
                 return this._pc.getLocalStreams();
             }
         } else {
             return [];
         }
     }
 
     getRemoteStreams() {
         let streams = [];
         for (let participant of new Set(this._participants.values())) {
             streams = streams.concat(participant.streams);
         }
         return streams;
     }
 
     getSenders() {
         if (this._pc !== null) {
            return this._pc.getSenders();
         } else {
             return [];
         }
     }
 
     getReceivers() {
         let receivers = [];
         for (let participant of new Set(this._participants.values())) {
             receivers =  receivers.concat(participant.getReceivers());
         }
         return receivers;
     }
 
     scaleLocalTrack(oldTrack, divider) {
         DEBUG('Scaling track by %d', divider);
 
         let sender;
 
         for (sender of this._pc.getSenders()) {
             if (sender.track === oldTrack) {
                 DEBUG('Found sender to modify track %o', sender);
                 break;
             }
         }
 
         sender.setParameters({encodings: [{scaleResolutionDownBy: divider}]})
             .then(() => {
                 DEBUG("Scale set to %o", divider);
                 DEBUG('Active encodings %o', sender.getParameters().encodings);
             })
             .catch((error) => {
                 DEBUG('Error %o', error);
             });
     }
 
     configureRoom(ps, cb=null) {
         if (!Array.isArray(ps)) {
             return;
         }
         this._sendConfigureRoom(ps, cb);
     }
 
     terminate() {
         if (this._terminated) {
             return;
         }
         DEBUG('Terminating conference');
         this._sendTerminate();
     }
 
     inviteParticipants(ps) {
         if (this._terminated) {
             return;
         }
         if (!Array.isArray(ps) || ps.length === 0) {
             return;
         }
         DEBUG('Inviting participants: %o', ps);
         const req = {
             sylkrtc: 'videoroom-invite',
             session: this.id,
             participants: ps
         };
         this._sendRequest(req, null);
     }
 
     // Private API
 
     _initialize(uri, options={}) {
         if (this._id !== null) {
             throw new Error('Already initialized');
         }
 
         if (uri.indexOf('@') === -1) {
             throw new Error('Invalid URI');
         }
 
         if (!options.localStream) {
             throw new Error('Missing localStream');
         }
 
         this._id = uuidv4();
         this._remoteIdentity = new utils.Identity(uri);
 
         options = Object.assign({}, options);
         const pcConfig = options.pcConfig || {iceServers:[]};
         this._pcConfig = pcConfig;
         this._initialParticipants = options.initialParticipants || [];
         const offerOptions = options.offerOptions || {};
         // only send audio / video through the publisher connection
         offerOptions.offerToReceiveAudio = false;
         offerOptions.offerToReceiveVideo = false;
         delete offerOptions.mandatory;
 
         // Create the RTCPeerConnection
         this._pc = new RTCPeerConnection(pcConfig);
         this._pc.addEventListener('icecandidate', (event) => {
             if (event.candidate !== null) {
                 DEBUG('New ICE candidate %o', event.candidate);
             } else {
                 DEBUG('ICE candidate gathering finished');
             }
             this._sendTrickle(event.candidate);
         });
 
         this._pc.addStream(options.localStream);
         this.emit('localStreamAdded', options.localStream);
         DEBUG('Offer options: %o', offerOptions);
         utils.createLocalSdp(this._pc, 'offer', offerOptions)
             .then((sdp) => {
                 DEBUG('Local SDP: %s', sdp);
                 this._sendJoin(sdp);
             })
             .catch((reason) => {
                 this._localTerminate(reason);
             });
     }
 
     _handleEvent(message) {
         DEBUG('Conference event: %o', message);
         let participant;
         switch (message.event) {
             case 'session-state':
                 let oldState = this._state;
                 let newState = message.state;
                 this._state = newState;
 
                 if (newState === 'accepted') {
                     this.emit('stateChanged', oldState, newState, {});
                     const sdp = utils.mungeSdp(message.sdp);
                     DEBUG('Remote SDP: %s', sdp);
                     this._setup_in_progress = true;
                     this._pc.setRemoteDescription(
                         new RTCSessionDescription({type: 'answer', sdp: sdp}),
                         // success
                         () => {
                             this._setup_in_progress = false;
                             if (!this._terminated) {
                                 if (this._delay_established) {
                                     oldState = this._state;
                                     this._state = 'established';
                                     DEBUG('Setting delayed established state!');
                                     this.emit('stateChanged', oldState, this._state, {});
                                     this._delay_established = false;
                                 }
                                 DEBUG('Conference accepted');
                                 if (this._initialParticipants.length > 0 ) {
                                     setTimeout(() => {
                                             this.inviteParticipants(this._initialParticipants);
                                     }, 50);
                                 }
                             }
                         },
                         // failure
                         (error) => {
                             DEBUG('Error processing conference accept: %s', error);
                             this.terminate();
                         }
                     );
                 } else if (newState === 'established') {
                     if (this._setup_in_progress) {
                         this._delay_established = true;
                     } else {
                         this.emit('stateChanged', oldState, newState, {});
                     }
                 } else if (newState === 'terminated') {
                     this.emit('stateChanged', oldState, newState, {reason: message.reason});
                     this._terminated = true;
                     this._close();
                 } else {
                     this.emit('stateChanged', oldState, newState, {});
                 }
                 break;
             case 'initial-publishers':
                 // this comes between 'accepted' and 'established' states
                 for (let p of message.publishers) {
                     participant = new Participant(p.id, new utils.Identity(p.uri, p.display_name), this);
                     this._participants.set(participant.id, participant);
                     this._participants.set(p.id, participant);
                 }
                 break;
             case 'publishers-joined':
                 for (let p of message.publishers) {
                     DEBUG('Participant joined: %o', p);
                     participant = new Participant(p.id, new utils.Identity(p.uri, p.display_name), this);
                     this._participants.set(participant.id, participant);
                     this._participants.set(p.id, participant);
                     this.emit('participantJoined', participant);
                 }
                 break;
             case 'publishers-left':
                 for (let pId of message.publishers) {
                     participant = this._participants.get(pId);
                     if (participant) {
                         this._participants.delete(participant.id);
                         this._participants.delete(pId);
                         this.emit('participantLeft', participant);
                     }
                 }
                 break;
             case 'feed-attached':
                 participant = this._participants.get(message.feed);
                 if (participant) {
                     participant._handleOffer(message.sdp);
                 }
                 break;
             case 'feed-established':
                 participant = this._participants.get(message.feed);
                 if (participant) {
                     participant._setState('established');
                 }
                 break;
             case 'configure':
                 let activeParticipants = [];
                 let originator;
                 const mappedOriginator = this._participants.get(message.originator);
 
                 if (mappedOriginator) {
                     originator = mappedOriginator.identity;
                 } else if (message.originator === this.id) {
                     originator = this.localIdentity;
                 } else if (message.originator === 'videoroom'){
                     originator = message.originator;
                 }
 
                 for (let pId of message.active_participants) {
                     participant = this._participants.get(pId);
                     if (participant) {
                         activeParticipants.push(participant);
                     } else if (pId === this.id) {
                         activeParticipants.push({
                             id: this.id,
                             publisherId: this.id,
                             identity: this.localIdentity,
                             streams: this.getLocalStreams()
                         });
                     }
                 }
                 this._activeParticpants = activeParticipants;
                 const roomConfig = {originator: originator, activeParticipants: this._activeParticpants};
                 this.emit('roomConfigured', roomConfig);
                 break;
             default:
                 break;
         }
     }
 
     _sendConfigureRoom(ps, cb = null) {
         const req = {
             sylkrtc: 'videoroom-configure',
             session: this.id,
             active_participants: ps
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Error configuring room: %s', error);
                 if (cb) {
                     cb(error);
                 }
             } else {
                 DEBUG('Configure room send: %o', ps);
             }
         });
     }
 
     _sendJoin(sdp) {
         const req = {
             sylkrtc: 'videoroom-join',
             account: this.account.id,
             session: this.id,
             uri: this.remoteIdentity.uri,
             sdp: sdp
         };
         DEBUG('Sending request: %o', req);
         this._sendRequest(req, (error) => {
             if (error) {
                 this._localTerminate(error);
             }
         });
     }
 
     _sendTerminate() {
         const req = {
             sylkrtc: 'videoroom-leave',
             session: this.id
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Error terminating conference: %s', error);
                 this._localTerminate(error);
             }
         });
         setTimeout(() => {
             if (!this._terminated) {
                 DEBUG('Timeout terminating call');
                 this._localTerminate('');
             }
             this._terminated = true;
         }, 150);
     }
 
     _sendTrickle(candidate) {
         const req = {
             sylkrtc: 'videoroom-session-trickle',
             session: this.id,
             candidates: candidate !== null ? [candidate] : []
         };
         this._sendRequest(req, (error) => {
             if (error) {
                 DEBUG('Trickle error: %s', error);
                 this._localTerminate(error);
             }
         });
     }
 
     _sendRequest(req, cb) {
         this._account._sendRequest(req, cb);
     }
 
     _close() {
         DEBUG('Closing RTCPeerConnection');
         if (this._pc !== null) {
             let tempStream;
             if (this._pc.getSenders) {
-                tempStream = new MediaStream();
+                let tracks = [];
                 for (let track of this._pc.getSenders()) {
-                    tempStream.addTrack(track.track);
+                    tracks = tracks.concat(track.track);
                 }
+                tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getLocalStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
 
             if (this._pc.getReceivers) {
-                tempStream = new MediaStream();
+                let tracks = [];
                 for (let track of this._pc.getReceivers()) {
-                    tempStream.addTrack(track.track);
+                    tracks = tracks.concat(track.track);
                 }
+                tempStream = new MediaStream(tracks);
                 utils.closeMediaStream(tempStream);
             } else {
                 for (let stream of this._pc.getRemoteStreams()) {
                     utils.closeMediaStream(stream);
                 }
             }
 
             this._pc.close();
             this._pc = null;
         }
         const participants = this.participants;
         this._participants = [];
         for (let p of participants) {
             p._close();
         }
     }
 
     _localTerminate(reason) {
         if (this._terminated) {
             return;
         }
         DEBUG(`Local terminate, reason: ${reason}`);
         this._account._confCalls.delete(this.id);
         this._terminated = true;
         const oldState = this._state;
         const newState = 'terminated';
         const data = {
             reason: reason.toString()
         };
         this._close();
         this.emit('stateChanged', oldState, newState, data);
     }
 
 }
 
 
 export { ConferenceCall };