集成rtc播放器

panlinlin
1 parent 2b1e5697
Showing 7 changed files with 7691 additions and 19 deletions
src/main/java/com/genersoft/iot/vmp/common/StreamInfo.java
src/main/java/com/genersoft/iot/vmp/media/zlm/ZLMHttpHookListener.java
src/main/java/com/genersoft/iot/vmp/service/impl/MediaServiceImpl.java
web_src/index.html
web_src/src/components/dialog/devicePlayer.vue
web_src/src/components/dialog/rtcPlayer.vue
web_src/static/js/ZLMRTCClient.js
@@ -18,6 +18,7 @@ public class StreamInfo {
     private String ws_ts;
     private String rtmp;
     private String rtsp;
+    private String rtc;
     private JSONArray tracks;
     public String getApp() {
@@ -139,4 +140,12 @@ public class StreamInfo {
     public void setStreamId(String streamId) {
         this.streamId = streamId;
     }
+
+    public String getRtc() {
+        return rtc;
+    }
+
+    public void setRtc(String rtc) {
+        this.rtc = rtc;
+    }
 }
@@ -4,6 +4,7 @@ import java.util.List;
 import java.util.UUID;
 import com.alibaba.fastjson.JSON;
+import com.alibaba.fastjson.JSONArray;
 import com.genersoft.iot.vmp.common.StreamInfo;
 import com.genersoft.iot.vmp.conf.MediaServerConfig;
 import com.genersoft.iot.vmp.gb28181.bean.Device;
@@ -239,26 +240,33 @@ public class ZLMHttpHookListener {
 		String app = json.getString("app");
 		String streamId = json.getString("stream");
 		String schema = json.getString("schema");
-		boolean regist = json.getBoolean("regist");
+		JSONArray tracks = json.getJSONArray("tracks");
+		String regist = json.getString("regist");
+		if (tracks != null) {
+			System.out.println("222222" + schema);
+		}
+		if ("rtmp".equals(schema)){
-		if ("rtp".equals(app) && !regist ) {
-			StreamInfo streamInfo = redisCatchStorage.queryPlayByStreamId(streamId);
-			if (streamInfo!=null){
-				redisCatchStorage.stopPlay(streamInfo);
-				storager.stopPlay(streamInfo.getDeviceID(), streamInfo.getChannelId());
-			}else{
-				streamInfo = redisCatchStorage.queryPlaybackByStreamId(streamId);
-				redisCatchStorage.stopPlayback(streamInfo);
-			}
-		}else {
-			if (!"rtp".equals(app) && "rtmp".equals(schema)){
-				if (regist) {
-					zlmMediaListManager.addMedia(app, streamId);
-				}else {
-					zlmMediaListManager.removeMedia(app, streamId);
+			if ("rtp".equals(app) && regist != null ) {
+				StreamInfo streamInfo = redisCatchStorage.queryPlayByStreamId(streamId);
+				if (streamInfo!=null){
+					redisCatchStorage.stopPlay(streamInfo);
+					storager.stopPlay(streamInfo.getDeviceID(), streamInfo.getChannelId());
+				}else{
+					streamInfo = redisCatchStorage.queryPlaybackByStreamId(streamId);
+					redisCatchStorage.stopPlayback(streamInfo);
+				}
+			}else {
+				if (!"rtp".equals(app) ){
+					if (regist == null) {
+						zlmMediaListManager.addMedia(app, streamId);
+					}else {
+						zlmMediaListManager.removeMedia(app, streamId);
+					}
 				}
 			}
 		}
+
 		JSONObject ret = new JSONObject();
 		ret.put("code", 0);
 		ret.put("msg", "success");
@@ -42,6 +42,8 @@ public class MediaServiceImpl implements IMediaService {
         streamInfoResult.setWs_fmp4(String.format("ws://%s:%s/%s/%s.live.mp4", mediaInfo.getWanIp(), mediaInfo.getHttpPort(), app,  stream));
         streamInfoResult.setTs(String.format("http://%s:%s/%s/%s.live.ts", mediaInfo.getWanIp(), mediaInfo.getHttpPort(), app,  stream));
         streamInfoResult.setWs_ts(String.format("ws://%s:%s/%s/%s.live.ts", mediaInfo.getWanIp(), mediaInfo.getHttpPort(), app,  stream));
+        streamInfoResult.setRtc(String.format("http://%s:%s/index/api/webrtc?app=%s&stream=%s&type=play", mediaInfo.getWanIp(), mediaInfo.getHttpPort(), app,  stream));
+
         return streamInfoResult;
     }
@@ -6,7 +6,8 @@
     <title>国标28181</title>
   </head>
   <body>
-    <script type="text/javascript" src="./js/EasyWasmPlayer.js"></script>
+    <!-- <script type="text/javascript" src="./js/EasyWasmPlayer.js"></script> -->
+    <script type="text/javascript" src="/static/js/ZLMRTCClient.js"></script>
     <script type="text/javascript" src="//api.map.baidu.com/api?v=2.0&ak=rk73w8dv1rkE4UdZsataG68VarhYQzrx&s=1"></script>
     <div id="app"></div>
     <!-- built files will be auto injected -->
@@ -136,7 +136,7 @@
 </template>
 <script>
-import player from '../dialog/player.vue'
+import player from '../dialog/rtcPlayer.vue'
 export default {
     name: 'devicePlayer',
     props: {},
@@ -250,7 +250,7 @@ export default {
             this.hasaudio = hasAudio;
             this.isLoging = false;
-            this.videoUrl = streamInfo.ws_flv;
+            this.videoUrl = streamInfo.rtc;
             this.streamId = streamInfo.streamId;
             this.app = streamInfo.app;
             this.playFromStreamInfo(false, streamInfo)
+<template>
+    <div id="rtcPlayer">
+        <video id='webRtcPlayerBox' controls autoplay style="text-align:left;">
+            Your browser is too old which doesn't support HTML5 video.
+          </video>
+    </div>
+</template>
+
+<script>
+export default {
+    name: 'rtcPlayer',
+    data() {
+        return {
+            webrtcPlayer: null
+        };
+    },
+    props: ['videoUrl', 'error', 'hasaudio'],
+    mounted () {
+       this.$nextTick(() =>{
+           console.log("初始化时的地址为: " + this.videoUrl)
+            this.play(this.videoUrl)
+        })
+    },
+    watch:{
+        videoUrl(newData, oldData){
+            this.pause();
+            this.play(newData);
+        },
+        immediate:true
+    },
+    methods: {
+        play: function (url) {
+            this.webrtcPlayer = new ZLMRTCClient.Endpoint({
+                element: document.getElementById('webRtcPlayerBox'),// video 标签
+                debug: true,// 是否打印日志
+                zlmsdpUrl: url,//流地址
+                simulecast: false,
+                useCamera: false,
+                audioEnable: false,
+                videoEnable: false,
+                recvOnly: true,
+            })
+            this.webrtcPlayer.on(ZLMRTCClient.Events.WEBRTC_ICE_CANDIDATE_ERROR,(e)=>{// ICE 协商出错
+                console.error('ICE 协商出错')
+                this.eventcallbacK("ICE ERROR", "ICE 协商出错")
+            });
+
+            this.webrtcPlayer.on(ZLMRTCClient.Events.WEBRTC_ON_REMOTE_STREAMS,(e)=>{//获取到了远端流，可以播放
+                console.error('播放成功',e.streams)
+                this.eventcallbacK("playing", "播放成功")
+            });
+
+            this.webrtcPlayer.on(ZLMRTCClient.Events.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED,(e)=>{// offer anwser 交换失败
+                console.error('offer anwser 交换失败',e)
+                this.eventcallbacK("OFFER ANSWER ERROR ", "offer anwser 交换失败")
+                if (e.code ==-400 && e.msg=="流不存在"){
+                    console.log("111111")
+                    setTimeout(()=>{
+                        this.webrtcPlayer.close();
+                        this.play(url)
+                    }, 100)
+                    
+                }
+            });
+
+            this.webrtcPlayer.on(ZLMRTCClient.Events.WEBRTC_ON_LOCAL_STREAM,(s)=>{// 获取到了本地流
+
+                // document.getElementById('selfVideo').srcObject=s;
+                this.eventcallbacK("LOCAL STREAM", "获取到了本地流")
+            });
+            
+        },
+        pause: function () {
+            if (this.webrtcPlayer != null) {
+                this.webrtcPlayer.close();
+                this.webrtcPlayer = null;
+            }
+            
+        },
+        eventcallbacK: function(type, message) {
+            console.log("player 事件回调")
+            console.log(type)
+            console.log(message)
+        }
+    },
+}
+</script>
+
+<style>
+    .LodingTitle {
+        min-width: 70px;
+    }
+    #rtcPlayer{
+        width: 100%;
+    }
+    #webRtcPlayerBox{
+        width: 100%;
+        max-height: 56vh;
+        background-color: #000;
+    }
+    /* 隐藏logo */
+    /* .iconqingxiLOGO {
+        display: none !important;
+    } */
+    
+</style>
 \ No newline at end of file
+var ZLMRTCClient = (function (exports) {
+	'use strict';
+
+	const Events$1 = {
+	  WEBRTC_NOT_SUPPORT: 'WEBRTC_NOT_SUPPORT',
+	  WEBRTC_ICE_CANDIDATE_ERROR: 'WEBRTC_ICE_CANDIDATE_ERROR',
+	  WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED: 'WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED',
+	  WEBRTC_ON_REMOTE_STREAMS: 'WEBRTC_ON_REMOTE_STREAMS',
+	  WEBRTC_ON_LOCAL_STREAM: 'WEBRTC_ON_LOCAL_STREAM'
+	};
+
+	const VERSION = '1.0.1';
+	const BUILD_DATE = 'Mon Apr 05 2021 10:22:48 GMT+0800 (中国标准时间)';
+
+	// Copyright (C) <2018> Intel Corporation
+	//
+	// SPDX-License-Identifier: Apache-2.0
+	// eslint-disable-next-line require-jsdoc
+	function isFirefox() {
+	  return window.navigator.userAgent.match('Firefox') !== null;
+	} // eslint-disable-next-line require-jsdoc
+
+	function isChrome() {
+	  return window.navigator.userAgent.match('Chrome') !== null;
+	} // eslint-disable-next-line require-jsdoc
+
+	function isEdge() {
+	  return window.navigator.userAgent.match(/Edge\/(\d+).(\d+)$/) !== null;
+	} // eslint-disable-next-line require-jsdoc
+
+	// Copyright (C) <2018> Intel Corporation
+	/**
+	 * @class AudioSourceInfo
+	 * @classDesc Source info about an audio track. Values: 'mic', 'screen-cast', 'file', 'mixed'.
+	 * @memberOf Owt.Base
+	 * @readonly
+	 * @enum {string}
+	 */
+
+	const AudioSourceInfo = {
+	  MIC: 'mic',
+	  SCREENCAST: 'screen-cast',
+	  FILE: 'file',
+	  MIXED: 'mixed'
+	};
+	/**
+	 * @class VideoSourceInfo
+	 * @classDesc Source info about a video track. Values: 'camera', 'screen-cast', 'file', 'mixed'.
+	 * @memberOf Owt.Base
+	 * @readonly
+	 * @enum {string}
+	 */
+
+	const VideoSourceInfo = {
+	  CAMERA: 'camera',
+	  SCREENCAST: 'screen-cast',
+	  FILE: 'file',
+	  MIXED: 'mixed'
+	};
+	/**
+	 * @class TrackKind
+	 * @classDesc Kind of a track. Values: 'audio' for audio track, 'video' for video track, 'av' for both audio and video tracks.
+	 * @memberOf Owt.Base
+	 * @readonly
+	 * @enum {string}
+	 */
+
+	const TrackKind = {
+	  /**
+	   * Audio tracks.
+	   * @type string
+	   */
+	  AUDIO: 'audio',
+
+	  /**
+	   * Video tracks.
+	   * @type string
+	   */
+	  VIDEO: 'video',
+
+	  /**
+	   * Both audio and video tracks.
+	   * @type string
+	   */
+	  AUDIO_AND_VIDEO: 'av'
+	};
+	/**
+	 * @class Resolution
+	 * @memberOf Owt.Base
+	 * @classDesc The Resolution defines the size of a rectangle.
+	 * @constructor
+	 * @param {number} width
+	 * @param {number} height
+	 */
+
+	class Resolution {
+	  // eslint-disable-next-line require-jsdoc
+	  constructor(width, height) {
+	    /**
+	     * @member {number} width
+	     * @instance
+	     * @memberof Owt.Base.Resolution
+	     */
+	    this.width = width;
+	    /**
+	     * @member {number} height
+	     * @instance
+	     * @memberof Owt.Base.Resolution
+	     */
+
+	    this.height = height;
+	  }
+
+	}
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	let logDisabled_ = true;
+	let deprecationWarnings_ = true;
+
+	/**
+	 * Extract browser version out of the provided user agent string.
+	 *
+	 * @param {!string} uastring userAgent string.
+	 * @param {!string} expr Regular expression used as match criteria.
+	 * @param {!number} pos position in the version string to be returned.
+	 * @return {!number} browser version.
+	 */
+	function extractVersion(uastring, expr, pos) {
+	  const match = uastring.match(expr);
+	  return match && match.length >= pos && parseInt(match[pos], 10);
+	}
+
+	// Wraps the peerconnection event eventNameToWrap in a function
+	// which returns the modified event object (or false to prevent
+	// the event).
+	function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+	  const proto = window.RTCPeerConnection.prototype;
+	  const nativeAddEventListener = proto.addEventListener;
+	  proto.addEventListener = function(nativeEventName, cb) {
+	    if (nativeEventName !== eventNameToWrap) {
+	      return nativeAddEventListener.apply(this, arguments);
+	    }
+	    const wrappedCallback = (e) => {
+	      const modifiedEvent = wrapper(e);
+	      if (modifiedEvent) {
+	        if (cb.handleEvent) {
+	          cb.handleEvent(modifiedEvent);
+	        } else {
+	          cb(modifiedEvent);
+	        }
+	      }
+	    };
+	    this._eventMap = this._eventMap || {};
+	    if (!this._eventMap[eventNameToWrap]) {
+	      this._eventMap[eventNameToWrap] = new Map();
+	    }
+	    this._eventMap[eventNameToWrap].set(cb, wrappedCallback);
+	    return nativeAddEventListener.apply(this, [nativeEventName,
+	      wrappedCallback]);
+	  };
+
+	  const nativeRemoveEventListener = proto.removeEventListener;
+	  proto.removeEventListener = function(nativeEventName, cb) {
+	    if (nativeEventName !== eventNameToWrap || !this._eventMap
+	        || !this._eventMap[eventNameToWrap]) {
+	      return nativeRemoveEventListener.apply(this, arguments);
+	    }
+	    if (!this._eventMap[eventNameToWrap].has(cb)) {
+	      return nativeRemoveEventListener.apply(this, arguments);
+	    }
+	    const unwrappedCb = this._eventMap[eventNameToWrap].get(cb);
+	    this._eventMap[eventNameToWrap].delete(cb);
+	    if (this._eventMap[eventNameToWrap].size === 0) {
+	      delete this._eventMap[eventNameToWrap];
+	    }
+	    if (Object.keys(this._eventMap).length === 0) {
+	      delete this._eventMap;
+	    }
+	    return nativeRemoveEventListener.apply(this, [nativeEventName,
+	      unwrappedCb]);
+	  };
+
+	  Object.defineProperty(proto, 'on' + eventNameToWrap, {
+	    get() {
+	      return this['_on' + eventNameToWrap];
+	    },
+	    set(cb) {
+	      if (this['_on' + eventNameToWrap]) {
+	        this.removeEventListener(eventNameToWrap,
+	            this['_on' + eventNameToWrap]);
+	        delete this['_on' + eventNameToWrap];
+	      }
+	      if (cb) {
+	        this.addEventListener(eventNameToWrap,
+	            this['_on' + eventNameToWrap] = cb);
+	      }
+	    },
+	    enumerable: true,
+	    configurable: true
+	  });
+	}
+
+	function disableLog(bool) {
+	  if (typeof bool !== 'boolean') {
+	    return new Error('Argument type: ' + typeof bool +
+	        '. Please use a boolean.');
+	  }
+	  logDisabled_ = bool;
+	  return (bool) ? 'adapter.js logging disabled' :
+	      'adapter.js logging enabled';
+	}
+
+	/**
+	 * Disable or enable deprecation warnings
+	 * @param {!boolean} bool set to true to disable warnings.
+	 */
+	function disableWarnings(bool) {
+	  if (typeof bool !== 'boolean') {
+	    return new Error('Argument type: ' + typeof bool +
+	        '. Please use a boolean.');
+	  }
+	  deprecationWarnings_ = !bool;
+	  return 'adapter.js deprecation warnings ' + (bool ? 'disabled' : 'enabled');
+	}
+
+	function log$1() {
+	  if (typeof window === 'object') {
+	    if (logDisabled_) {
+	      return;
+	    }
+	    if (typeof console !== 'undefined' && typeof console.log === 'function') {
+	      console.log.apply(console, arguments);
+	    }
+	  }
+	}
+
+	/**
+	 * Shows a deprecation warning suggesting the modern and spec-compatible API.
+	 */
+	function deprecated(oldMethod, newMethod) {
+	  if (!deprecationWarnings_) {
+	    return;
+	  }
+	  console.warn(oldMethod + ' is deprecated, please use ' + newMethod +
+	      ' instead.');
+	}
+
+	/**
+	 * Browser detector.
+	 *
+	 * @return {object} result containing browser and version
+	 *     properties.
+	 */
+	function detectBrowser(window) {
+	  // Returned result object.
+	  const result = {browser: null, version: null};
+
+	  // Fail early if it's not a browser
+	  if (typeof window === 'undefined' || !window.navigator) {
+	    result.browser = 'Not a browser.';
+	    return result;
+	  }
+
+	  const {navigator} = window;
+
+	  if (navigator.mozGetUserMedia) { // Firefox.
+	    result.browser = 'firefox';
+	    result.version = extractVersion(navigator.userAgent,
+	        /Firefox\/(\d+)\./, 1);
+	  } else if (navigator.webkitGetUserMedia ||
+	      (window.isSecureContext === false && window.webkitRTCPeerConnection &&
+	       !window.RTCIceGatherer)) {
+	    // Chrome, Chromium, Webview, Opera.
+	    // Version matches Chrome/WebRTC version.
+	    // Chrome 74 removed webkitGetUserMedia on http as well so we need the
+	    // more complicated fallback to webkitRTCPeerConnection.
+	    result.browser = 'chrome';
+	    result.version = extractVersion(navigator.userAgent,
+	        /Chrom(e|ium)\/(\d+)\./, 2);
+	  } else if (navigator.mediaDevices &&
+	      navigator.userAgent.match(/Edge\/(\d+).(\d+)$/)) { // Edge.
+	    result.browser = 'edge';
+	    result.version = extractVersion(navigator.userAgent,
+	        /Edge\/(\d+).(\d+)$/, 2);
+	  } else if (window.RTCPeerConnection &&
+	      navigator.userAgent.match(/AppleWebKit\/(\d+)\./)) { // Safari.
+	    result.browser = 'safari';
+	    result.version = extractVersion(navigator.userAgent,
+	        /AppleWebKit\/(\d+)\./, 1);
+	    result.supportsUnifiedPlan = window.RTCRtpTransceiver &&
+	        'currentDirection' in window.RTCRtpTransceiver.prototype;
+	  } else { // Default fallthrough: not supported.
+	    result.browser = 'Not a supported browser.';
+	    return result;
+	  }
+
+	  return result;
+	}
+
+	/**
+	 * Checks if something is an object.
+	 *
+	 * @param {*} val The something you want to check.
+	 * @return true if val is an object, false otherwise.
+	 */
+	function isObject$1(val) {
+	  return Object.prototype.toString.call(val) === '[object Object]';
+	}
+
+	/**
+	 * Remove all empty objects and undefined values
+	 * from a nested object -- an enhanced and vanilla version
+	 * of Lodash's `compact`.
+	 */
+	function compactObject(data) {
+	  if (!isObject$1(data)) {
+	    return data;
+	  }
+
+	  return Object.keys(data).reduce(function(accumulator, key) {
+	    const isObj = isObject$1(data[key]);
+	    const value = isObj ? compactObject(data[key]) : data[key];
+	    const isEmptyObject = isObj && !Object.keys(value).length;
+	    if (value === undefined || isEmptyObject) {
+	      return accumulator;
+	    }
+	    return Object.assign(accumulator, {[key]: value});
+	  }, {});
+	}
+
+	/* iterates the stats graph recursively. */
+	function walkStats(stats, base, resultSet) {
+	  if (!base || resultSet.has(base.id)) {
+	    return;
+	  }
+	  resultSet.set(base.id, base);
+	  Object.keys(base).forEach(name => {
+	    if (name.endsWith('Id')) {
+	      walkStats(stats, stats.get(base[name]), resultSet);
+	    } else if (name.endsWith('Ids')) {
+	      base[name].forEach(id => {
+	        walkStats(stats, stats.get(id), resultSet);
+	      });
+	    }
+	  });
+	}
+
+	/* filter getStats for a sender/receiver track. */
+	function filterStats(result, track, outbound) {
+	  const streamStatsType = outbound ? 'outbound-rtp' : 'inbound-rtp';
+	  const filteredResult = new Map();
+	  if (track === null) {
+	    return filteredResult;
+	  }
+	  const trackStats = [];
+	  result.forEach(value => {
+	    if (value.type === 'track' &&
+	        value.trackIdentifier === track.id) {
+	      trackStats.push(value);
+	    }
+	  });
+	  trackStats.forEach(trackStat => {
+	    result.forEach(stats => {
+	      if (stats.type === streamStatsType && stats.trackId === trackStat.id) {
+	        walkStats(result, stats, filteredResult);
+	      }
+	    });
+	  });
+	  return filteredResult;
+	}
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+	const logging = log$1;
+
+	function shimGetUserMedia$3(window, browserDetails) {
+	  const navigator = window && window.navigator;
+
+	  if (!navigator.mediaDevices) {
+	    return;
+	  }
+
+	  const constraintsToChrome_ = function(c) {
+	    if (typeof c !== 'object' || c.mandatory || c.optional) {
+	      return c;
+	    }
+	    const cc = {};
+	    Object.keys(c).forEach(key => {
+	      if (key === 'require' || key === 'advanced' || key === 'mediaSource') {
+	        return;
+	      }
+	      const r = (typeof c[key] === 'object') ? c[key] : {ideal: c[key]};
+	      if (r.exact !== undefined && typeof r.exact === 'number') {
+	        r.min = r.max = r.exact;
+	      }
+	      const oldname_ = function(prefix, name) {
+	        if (prefix) {
+	          return prefix + name.charAt(0).toUpperCase() + name.slice(1);
+	        }
+	        return (name === 'deviceId') ? 'sourceId' : name;
+	      };
+	      if (r.ideal !== undefined) {
+	        cc.optional = cc.optional || [];
+	        let oc = {};
+	        if (typeof r.ideal === 'number') {
+	          oc[oldname_('min', key)] = r.ideal;
+	          cc.optional.push(oc);
+	          oc = {};
+	          oc[oldname_('max', key)] = r.ideal;
+	          cc.optional.push(oc);
+	        } else {
+	          oc[oldname_('', key)] = r.ideal;
+	          cc.optional.push(oc);
+	        }
+	      }
+	      if (r.exact !== undefined && typeof r.exact !== 'number') {
+	        cc.mandatory = cc.mandatory || {};
+	        cc.mandatory[oldname_('', key)] = r.exact;
+	      } else {
+	        ['min', 'max'].forEach(mix => {
+	          if (r[mix] !== undefined) {
+	            cc.mandatory = cc.mandatory || {};
+	            cc.mandatory[oldname_(mix, key)] = r[mix];
+	          }
+	        });
+	      }
+	    });
+	    if (c.advanced) {
+	      cc.optional = (cc.optional || []).concat(c.advanced);
+	    }
+	    return cc;
+	  };
+
+	  const shimConstraints_ = function(constraints, func) {
+	    if (browserDetails.version >= 61) {
+	      return func(constraints);
+	    }
+	    constraints = JSON.parse(JSON.stringify(constraints));
+	    if (constraints && typeof constraints.audio === 'object') {
+	      const remap = function(obj, a, b) {
+	        if (a in obj && !(b in obj)) {
+	          obj[b] = obj[a];
+	          delete obj[a];
+	        }
+	      };
+	      constraints = JSON.parse(JSON.stringify(constraints));
+	      remap(constraints.audio, 'autoGainControl', 'googAutoGainControl');
+	      remap(constraints.audio, 'noiseSuppression', 'googNoiseSuppression');
+	      constraints.audio = constraintsToChrome_(constraints.audio);
+	    }
+	    if (constraints && typeof constraints.video === 'object') {
+	      // Shim facingMode for mobile & surface pro.
+	      let face = constraints.video.facingMode;
+	      face = face && ((typeof face === 'object') ? face : {ideal: face});
+	      const getSupportedFacingModeLies = browserDetails.version < 66;
+
+	      if ((face && (face.exact === 'user' || face.exact === 'environment' ||
+	                    face.ideal === 'user' || face.ideal === 'environment')) &&
+	          !(navigator.mediaDevices.getSupportedConstraints &&
+	            navigator.mediaDevices.getSupportedConstraints().facingMode &&
+	            !getSupportedFacingModeLies)) {
+	        delete constraints.video.facingMode;
+	        let matches;
+	        if (face.exact === 'environment' || face.ideal === 'environment') {
+	          matches = ['back', 'rear'];
+	        } else if (face.exact === 'user' || face.ideal === 'user') {
+	          matches = ['front'];
+	        }
+	        if (matches) {
+	          // Look for matches in label, or use last cam for back (typical).
+	          return navigator.mediaDevices.enumerateDevices()
+	          .then(devices => {
+	            devices = devices.filter(d => d.kind === 'videoinput');
+	            let dev = devices.find(d => matches.some(match =>
+	              d.label.toLowerCase().includes(match)));
+	            if (!dev && devices.length && matches.includes('back')) {
+	              dev = devices[devices.length - 1]; // more likely the back cam
+	            }
+	            if (dev) {
+	              constraints.video.deviceId = face.exact ? {exact: dev.deviceId} :
+	                                                        {ideal: dev.deviceId};
+	            }
+	            constraints.video = constraintsToChrome_(constraints.video);
+	            logging('chrome: ' + JSON.stringify(constraints));
+	            return func(constraints);
+	          });
+	        }
+	      }
+	      constraints.video = constraintsToChrome_(constraints.video);
+	    }
+	    logging('chrome: ' + JSON.stringify(constraints));
+	    return func(constraints);
+	  };
+
+	  const shimError_ = function(e) {
+	    if (browserDetails.version >= 64) {
+	      return e;
+	    }
+	    return {
+	      name: {
+	        PermissionDeniedError: 'NotAllowedError',
+	        PermissionDismissedError: 'NotAllowedError',
+	        InvalidStateError: 'NotAllowedError',
+	        DevicesNotFoundError: 'NotFoundError',
+	        ConstraintNotSatisfiedError: 'OverconstrainedError',
+	        TrackStartError: 'NotReadableError',
+	        MediaDeviceFailedDueToShutdown: 'NotAllowedError',
+	        MediaDeviceKillSwitchOn: 'NotAllowedError',
+	        TabCaptureError: 'AbortError',
+	        ScreenCaptureError: 'AbortError',
+	        DeviceCaptureError: 'AbortError'
+	      }[e.name] || e.name,
+	      message: e.message,
+	      constraint: e.constraint || e.constraintName,
+	      toString() {
+	        return this.name + (this.message && ': ') + this.message;
+	      }
+	    };
+	  };
+
+	  const getUserMedia_ = function(constraints, onSuccess, onError) {
+	    shimConstraints_(constraints, c => {
+	      navigator.webkitGetUserMedia(c, onSuccess, e => {
+	        if (onError) {
+	          onError(shimError_(e));
+	        }
+	      });
+	    });
+	  };
+	  navigator.getUserMedia = getUserMedia_.bind(navigator);
+
+	  // Even though Chrome 45 has navigator.mediaDevices and a getUserMedia
+	  // function which returns a Promise, it does not accept spec-style
+	  // constraints.
+	  if (navigator.mediaDevices.getUserMedia) {
+	    const origGetUserMedia = navigator.mediaDevices.getUserMedia.
+	        bind(navigator.mediaDevices);
+	    navigator.mediaDevices.getUserMedia = function(cs) {
+	      return shimConstraints_(cs, c => origGetUserMedia(c).then(stream => {
+	        if (c.audio && !stream.getAudioTracks().length ||
+	            c.video && !stream.getVideoTracks().length) {
+	          stream.getTracks().forEach(track => {
+	            track.stop();
+	          });
+	          throw new DOMException('', 'NotFoundError');
+	        }
+	        return stream;
+	      }, e => Promise.reject(shimError_(e))));
+	    };
+	  }
+	}
+
+	/*
+	 *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+	function shimGetDisplayMedia$2(window, getSourceId) {
+	  if (window.navigator.mediaDevices &&
+	    'getDisplayMedia' in window.navigator.mediaDevices) {
+	    return;
+	  }
+	  if (!(window.navigator.mediaDevices)) {
+	    return;
+	  }
+	  // getSourceId is a function that returns a promise resolving with
+	  // the sourceId of the screen/window/tab to be shared.
+	  if (typeof getSourceId !== 'function') {
+	    console.error('shimGetDisplayMedia: getSourceId argument is not ' +
+	        'a function');
+	    return;
+	  }
+	  window.navigator.mediaDevices.getDisplayMedia =
+	    function getDisplayMedia(constraints) {
+	      return getSourceId(constraints)
+	        .then(sourceId => {
+	          const widthSpecified = constraints.video && constraints.video.width;
+	          const heightSpecified = constraints.video &&
+	            constraints.video.height;
+	          const frameRateSpecified = constraints.video &&
+	            constraints.video.frameRate;
+	          constraints.video = {
+	            mandatory: {
+	              chromeMediaSource: 'desktop',
+	              chromeMediaSourceId: sourceId,
+	              maxFrameRate: frameRateSpecified || 3
+	            }
+	          };
+	          if (widthSpecified) {
+	            constraints.video.mandatory.maxWidth = widthSpecified;
+	          }
+	          if (heightSpecified) {
+	            constraints.video.mandatory.maxHeight = heightSpecified;
+	          }
+	          return window.navigator.mediaDevices.getUserMedia(constraints);
+	        });
+	    };
+	}
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimMediaStream(window) {
+	  window.MediaStream = window.MediaStream || window.webkitMediaStream;
+	}
+
+	function shimOnTrack$1(window) {
+	  if (typeof window === 'object' && window.RTCPeerConnection && !('ontrack' in
+	      window.RTCPeerConnection.prototype)) {
+	    Object.defineProperty(window.RTCPeerConnection.prototype, 'ontrack', {
+	      get() {
+	        return this._ontrack;
+	      },
+	      set(f) {
+	        if (this._ontrack) {
+	          this.removeEventListener('track', this._ontrack);
+	        }
+	        this.addEventListener('track', this._ontrack = f);
+	      },
+	      enumerable: true,
+	      configurable: true
+	    });
+	    const origSetRemoteDescription =
+	        window.RTCPeerConnection.prototype.setRemoteDescription;
+	    window.RTCPeerConnection.prototype.setRemoteDescription =
+	      function setRemoteDescription() {
+	        if (!this._ontrackpoly) {
+	          this._ontrackpoly = (e) => {
+	            // onaddstream does not fire when a track is added to an existing
+	            // stream. But stream.onaddtrack is implemented so we use that.
+	            e.stream.addEventListener('addtrack', te => {
+	              let receiver;
+	              if (window.RTCPeerConnection.prototype.getReceivers) {
+	                receiver = this.getReceivers()
+	                  .find(r => r.track && r.track.id === te.track.id);
+	              } else {
+	                receiver = {track: te.track};
+	              }
+
+	              const event = new Event('track');
+	              event.track = te.track;
+	              event.receiver = receiver;
+	              event.transceiver = {receiver};
+	              event.streams = [e.stream];
+	              this.dispatchEvent(event);
+	            });
+	            e.stream.getTracks().forEach(track => {
+	              let receiver;
+	              if (window.RTCPeerConnection.prototype.getReceivers) {
+	                receiver = this.getReceivers()
+	                  .find(r => r.track && r.track.id === track.id);
+	              } else {
+	                receiver = {track};
+	              }
+	              const event = new Event('track');
+	              event.track = track;
+	              event.receiver = receiver;
+	              event.transceiver = {receiver};
+	              event.streams = [e.stream];
+	              this.dispatchEvent(event);
+	            });
+	          };
+	          this.addEventListener('addstream', this._ontrackpoly);
+	        }
+	        return origSetRemoteDescription.apply(this, arguments);
+	      };
+	  } else {
+	    // even if RTCRtpTransceiver is in window, it is only used and
+	    // emitted in unified-plan. Unfortunately this means we need
+	    // to unconditionally wrap the event.
+	    wrapPeerConnectionEvent(window, 'track', e => {
+	      if (!e.transceiver) {
+	        Object.defineProperty(e, 'transceiver',
+	          {value: {receiver: e.receiver}});
+	      }
+	      return e;
+	    });
+	  }
+	}
+
+	function shimGetSendersWithDtmf(window) {
+	  // Overrides addTrack/removeTrack, depends on shimAddTrackRemoveTrack.
+	  if (typeof window === 'object' && window.RTCPeerConnection &&
+	      !('getSenders' in window.RTCPeerConnection.prototype) &&
+	      'createDTMFSender' in window.RTCPeerConnection.prototype) {
+	    const shimSenderWithDtmf = function(pc, track) {
+	      return {
+	        track,
+	        get dtmf() {
+	          if (this._dtmf === undefined) {
+	            if (track.kind === 'audio') {
+	              this._dtmf = pc.createDTMFSender(track);
+	            } else {
+	              this._dtmf = null;
+	            }
+	          }
+	          return this._dtmf;
+	        },
+	        _pc: pc
+	      };
+	    };
+
+	    // augment addTrack when getSenders is not available.
+	    if (!window.RTCPeerConnection.prototype.getSenders) {
+	      window.RTCPeerConnection.prototype.getSenders = function getSenders() {
+	        this._senders = this._senders || [];
+	        return this._senders.slice(); // return a copy of the internal state.
+	      };
+	      const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
+	      window.RTCPeerConnection.prototype.addTrack =
+	        function addTrack(track, stream) {
+	          let sender = origAddTrack.apply(this, arguments);
+	          if (!sender) {
+	            sender = shimSenderWithDtmf(this, track);
+	            this._senders.push(sender);
+	          }
+	          return sender;
+	        };
+
+	      const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack;
+	      window.RTCPeerConnection.prototype.removeTrack =
+	        function removeTrack(sender) {
+	          origRemoveTrack.apply(this, arguments);
+	          const idx = this._senders.indexOf(sender);
+	          if (idx !== -1) {
+	            this._senders.splice(idx, 1);
+	          }
+	        };
+	    }
+	    const origAddStream = window.RTCPeerConnection.prototype.addStream;
+	    window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
+	      this._senders = this._senders || [];
+	      origAddStream.apply(this, [stream]);
+	      stream.getTracks().forEach(track => {
+	        this._senders.push(shimSenderWithDtmf(this, track));
+	      });
+	    };
+
+	    const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
+	    window.RTCPeerConnection.prototype.removeStream =
+	      function removeStream(stream) {
+	        this._senders = this._senders || [];
+	        origRemoveStream.apply(this, [stream]);
+
+	        stream.getTracks().forEach(track => {
+	          const sender = this._senders.find(s => s.track === track);
+	          if (sender) { // remove sender
+	            this._senders.splice(this._senders.indexOf(sender), 1);
+	          }
+	        });
+	      };
+	  } else if (typeof window === 'object' && window.RTCPeerConnection &&
+	             'getSenders' in window.RTCPeerConnection.prototype &&
+	             'createDTMFSender' in window.RTCPeerConnection.prototype &&
+	             window.RTCRtpSender &&
+	             !('dtmf' in window.RTCRtpSender.prototype)) {
+	    const origGetSenders = window.RTCPeerConnection.prototype.getSenders;
+	    window.RTCPeerConnection.prototype.getSenders = function getSenders() {
+	      const senders = origGetSenders.apply(this, []);
+	      senders.forEach(sender => sender._pc = this);
+	      return senders;
+	    };
+
+	    Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
+	      get() {
+	        if (this._dtmf === undefined) {
+	          if (this.track.kind === 'audio') {
+	            this._dtmf = this._pc.createDTMFSender(this.track);
+	          } else {
+	            this._dtmf = null;
+	          }
+	        }
+	        return this._dtmf;
+	      }
+	    });
+	  }
+	}
+
+	function shimGetStats(window) {
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+
+	  const origGetStats = window.RTCPeerConnection.prototype.getStats;
+	  window.RTCPeerConnection.prototype.getStats = function getStats() {
+	    const [selector, onSucc, onErr] = arguments;
+
+	    // If selector is a function then we are in the old style stats so just
+	    // pass back the original getStats format to avoid breaking old users.
+	    if (arguments.length > 0 && typeof selector === 'function') {
+	      return origGetStats.apply(this, arguments);
+	    }
+
+	    // When spec-style getStats is supported, return those when called with
+	    // either no arguments or the selector argument is null.
+	    if (origGetStats.length === 0 && (arguments.length === 0 ||
+	        typeof selector !== 'function')) {
+	      return origGetStats.apply(this, []);
+	    }
+
+	    const fixChromeStats_ = function(response) {
+	      const standardReport = {};
+	      const reports = response.result();
+	      reports.forEach(report => {
+	        const standardStats = {
+	          id: report.id,
+	          timestamp: report.timestamp,
+	          type: {
+	            localcandidate: 'local-candidate',
+	            remotecandidate: 'remote-candidate'
+	          }[report.type] || report.type
+	        };
+	        report.names().forEach(name => {
+	          standardStats[name] = report.stat(name);
+	        });
+	        standardReport[standardStats.id] = standardStats;
+	      });
+
+	      return standardReport;
+	    };
+
+	    // shim getStats with maplike support
+	    const makeMapStats = function(stats) {
+	      return new Map(Object.keys(stats).map(key => [key, stats[key]]));
+	    };
+
+	    if (arguments.length >= 2) {
+	      const successCallbackWrapper_ = function(response) {
+	        onSucc(makeMapStats(fixChromeStats_(response)));
+	      };
+
+	      return origGetStats.apply(this, [successCallbackWrapper_,
+	        selector]);
+	    }
+
+	    // promise-support
+	    return new Promise((resolve, reject) => {
+	      origGetStats.apply(this, [
+	        function(response) {
+	          resolve(makeMapStats(fixChromeStats_(response)));
+	        }, reject]);
+	    }).then(onSucc, onErr);
+	  };
+	}
+
+	function shimSenderReceiverGetStats(window) {
+	  if (!(typeof window === 'object' && window.RTCPeerConnection &&
+	      window.RTCRtpSender && window.RTCRtpReceiver)) {
+	    return;
+	  }
+
+	  // shim sender stats.
+	  if (!('getStats' in window.RTCRtpSender.prototype)) {
+	    const origGetSenders = window.RTCPeerConnection.prototype.getSenders;
+	    if (origGetSenders) {
+	      window.RTCPeerConnection.prototype.getSenders = function getSenders() {
+	        const senders = origGetSenders.apply(this, []);
+	        senders.forEach(sender => sender._pc = this);
+	        return senders;
+	      };
+	    }
+
+	    const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
+	    if (origAddTrack) {
+	      window.RTCPeerConnection.prototype.addTrack = function addTrack() {
+	        const sender = origAddTrack.apply(this, arguments);
+	        sender._pc = this;
+	        return sender;
+	      };
+	    }
+	    window.RTCRtpSender.prototype.getStats = function getStats() {
+	      const sender = this;
+	      return this._pc.getStats().then(result =>
+	        /* Note: this will include stats of all senders that
+	         *   send a track with the same id as sender.track as
+	         *   it is not possible to identify the RTCRtpSender.
+	         */
+	        filterStats(result, sender.track, true));
+	    };
+	  }
+
+	  // shim receiver stats.
+	  if (!('getStats' in window.RTCRtpReceiver.prototype)) {
+	    const origGetReceivers = window.RTCPeerConnection.prototype.getReceivers;
+	    if (origGetReceivers) {
+	      window.RTCPeerConnection.prototype.getReceivers =
+	        function getReceivers() {
+	          const receivers = origGetReceivers.apply(this, []);
+	          receivers.forEach(receiver => receiver._pc = this);
+	          return receivers;
+	        };
+	    }
+	    wrapPeerConnectionEvent(window, 'track', e => {
+	      e.receiver._pc = e.srcElement;
+	      return e;
+	    });
+	    window.RTCRtpReceiver.prototype.getStats = function getStats() {
+	      const receiver = this;
+	      return this._pc.getStats().then(result =>
+	        filterStats(result, receiver.track, false));
+	    };
+	  }
+
+	  if (!('getStats' in window.RTCRtpSender.prototype &&
+	      'getStats' in window.RTCRtpReceiver.prototype)) {
+	    return;
+	  }
+
+	  // shim RTCPeerConnection.getStats(track).
+	  const origGetStats = window.RTCPeerConnection.prototype.getStats;
+	  window.RTCPeerConnection.prototype.getStats = function getStats() {
+	    if (arguments.length > 0 &&
+	        arguments[0] instanceof window.MediaStreamTrack) {
+	      const track = arguments[0];
+	      let sender;
+	      let receiver;
+	      let err;
+	      this.getSenders().forEach(s => {
+	        if (s.track === track) {
+	          if (sender) {
+	            err = true;
+	          } else {
+	            sender = s;
+	          }
+	        }
+	      });
+	      this.getReceivers().forEach(r => {
+	        if (r.track === track) {
+	          if (receiver) {
+	            err = true;
+	          } else {
+	            receiver = r;
+	          }
+	        }
+	        return r.track === track;
+	      });
+	      if (err || (sender && receiver)) {
+	        return Promise.reject(new DOMException(
+	          'There are more than one sender or receiver for the track.',
+	          'InvalidAccessError'));
+	      } else if (sender) {
+	        return sender.getStats();
+	      } else if (receiver) {
+	        return receiver.getStats();
+	      }
+	      return Promise.reject(new DOMException(
+	        'There is no sender or receiver for the track.',
+	        'InvalidAccessError'));
+	    }
+	    return origGetStats.apply(this, arguments);
+	  };
+	}
+
+	function shimAddTrackRemoveTrackWithNative(window) {
+	  // shim addTrack/removeTrack with native variants in order to make
+	  // the interactions with legacy getLocalStreams behave as in other browsers.
+	  // Keeps a mapping stream.id => [stream, rtpsenders...]
+	  window.RTCPeerConnection.prototype.getLocalStreams =
+	    function getLocalStreams() {
+	      this._shimmedLocalStreams = this._shimmedLocalStreams || {};
+	      return Object.keys(this._shimmedLocalStreams)
+	        .map(streamId => this._shimmedLocalStreams[streamId][0]);
+	    };
+
+	  const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
+	  window.RTCPeerConnection.prototype.addTrack =
+	    function addTrack(track, stream) {
+	      if (!stream) {
+	        return origAddTrack.apply(this, arguments);
+	      }
+	      this._shimmedLocalStreams = this._shimmedLocalStreams || {};
+
+	      const sender = origAddTrack.apply(this, arguments);
+	      if (!this._shimmedLocalStreams[stream.id]) {
+	        this._shimmedLocalStreams[stream.id] = [stream, sender];
+	      } else if (this._shimmedLocalStreams[stream.id].indexOf(sender) === -1) {
+	        this._shimmedLocalStreams[stream.id].push(sender);
+	      }
+	      return sender;
+	    };
+
+	  const origAddStream = window.RTCPeerConnection.prototype.addStream;
+	  window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
+	    this._shimmedLocalStreams = this._shimmedLocalStreams || {};
+
+	    stream.getTracks().forEach(track => {
+	      const alreadyExists = this.getSenders().find(s => s.track === track);
+	      if (alreadyExists) {
+	        throw new DOMException('Track already exists.',
+	            'InvalidAccessError');
+	      }
+	    });
+	    const existingSenders = this.getSenders();
+	    origAddStream.apply(this, arguments);
+	    const newSenders = this.getSenders()
+	      .filter(newSender => existingSenders.indexOf(newSender) === -1);
+	    this._shimmedLocalStreams[stream.id] = [stream].concat(newSenders);
+	  };
+
+	  const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
+	  window.RTCPeerConnection.prototype.removeStream =
+	    function removeStream(stream) {
+	      this._shimmedLocalStreams = this._shimmedLocalStreams || {};
+	      delete this._shimmedLocalStreams[stream.id];
+	      return origRemoveStream.apply(this, arguments);
+	    };
+
+	  const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack;
+	  window.RTCPeerConnection.prototype.removeTrack =
+	    function removeTrack(sender) {
+	      this._shimmedLocalStreams = this._shimmedLocalStreams || {};
+	      if (sender) {
+	        Object.keys(this._shimmedLocalStreams).forEach(streamId => {
+	          const idx = this._shimmedLocalStreams[streamId].indexOf(sender);
+	          if (idx !== -1) {
+	            this._shimmedLocalStreams[streamId].splice(idx, 1);
+	          }
+	          if (this._shimmedLocalStreams[streamId].length === 1) {
+	            delete this._shimmedLocalStreams[streamId];
+	          }
+	        });
+	      }
+	      return origRemoveTrack.apply(this, arguments);
+	    };
+	}
+
+	function shimAddTrackRemoveTrack(window, browserDetails) {
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+	  // shim addTrack and removeTrack.
+	  if (window.RTCPeerConnection.prototype.addTrack &&
+	      browserDetails.version >= 65) {
+	    return shimAddTrackRemoveTrackWithNative(window);
+	  }
+
+	  // also shim pc.getLocalStreams when addTrack is shimmed
+	  // to return the original streams.
+	  const origGetLocalStreams = window.RTCPeerConnection.prototype
+	      .getLocalStreams;
+	  window.RTCPeerConnection.prototype.getLocalStreams =
+	    function getLocalStreams() {
+	      const nativeStreams = origGetLocalStreams.apply(this);
+	      this._reverseStreams = this._reverseStreams || {};
+	      return nativeStreams.map(stream => this._reverseStreams[stream.id]);
+	    };
+
+	  const origAddStream = window.RTCPeerConnection.prototype.addStream;
+	  window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
+	    this._streams = this._streams || {};
+	    this._reverseStreams = this._reverseStreams || {};
+
+	    stream.getTracks().forEach(track => {
+	      const alreadyExists = this.getSenders().find(s => s.track === track);
+	      if (alreadyExists) {
+	        throw new DOMException('Track already exists.',
+	            'InvalidAccessError');
+	      }
+	    });
+	    // Add identity mapping for consistency with addTrack.
+	    // Unless this is being used with a stream from addTrack.
+	    if (!this._reverseStreams[stream.id]) {
+	      const newStream = new window.MediaStream(stream.getTracks());
+	      this._streams[stream.id] = newStream;
+	      this._reverseStreams[newStream.id] = stream;
+	      stream = newStream;
+	    }
+	    origAddStream.apply(this, [stream]);
+	  };
+
+	  const origRemoveStream = window.RTCPeerConnection.prototype.removeStream;
+	  window.RTCPeerConnection.prototype.removeStream =
+	    function removeStream(stream) {
+	      this._streams = this._streams || {};
+	      this._reverseStreams = this._reverseStreams || {};
+
+	      origRemoveStream.apply(this, [(this._streams[stream.id] || stream)]);
+	      delete this._reverseStreams[(this._streams[stream.id] ?
+	          this._streams[stream.id].id : stream.id)];
+	      delete this._streams[stream.id];
+	    };
+
+	  window.RTCPeerConnection.prototype.addTrack =
+	    function addTrack(track, stream) {
+	      if (this.signalingState === 'closed') {
+	        throw new DOMException(
+	          'The RTCPeerConnection\'s signalingState is \'closed\'.',
+	          'InvalidStateError');
+	      }
+	      const streams = [].slice.call(arguments, 1);
+	      if (streams.length !== 1 ||
+	          !streams[0].getTracks().find(t => t === track)) {
+	        // this is not fully correct but all we can manage without
+	        // [[associated MediaStreams]] internal slot.
+	        throw new DOMException(
+	          'The adapter.js addTrack polyfill only supports a single ' +
+	          ' stream which is associated with the specified track.',
+	          'NotSupportedError');
+	      }
+
+	      const alreadyExists = this.getSenders().find(s => s.track === track);
+	      if (alreadyExists) {
+	        throw new DOMException('Track already exists.',
+	            'InvalidAccessError');
+	      }
+
+	      this._streams = this._streams || {};
+	      this._reverseStreams = this._reverseStreams || {};
+	      const oldStream = this._streams[stream.id];
+	      if (oldStream) {
+	        // this is using odd Chrome behaviour, use with caution:
+	        // https://bugs.chromium.org/p/webrtc/issues/detail?id=7815
+	        // Note: we rely on the high-level addTrack/dtmf shim to
+	        // create the sender with a dtmf sender.
+	        oldStream.addTrack(track);
+
+	        // Trigger ONN async.
+	        Promise.resolve().then(() => {
+	          this.dispatchEvent(new Event('negotiationneeded'));
+	        });
+	      } else {
+	        const newStream = new window.MediaStream([track]);
+	        this._streams[stream.id] = newStream;
+	        this._reverseStreams[newStream.id] = stream;
+	        this.addStream(newStream);
+	      }
+	      return this.getSenders().find(s => s.track === track);
+	    };
+
+	  // replace the internal stream id with the external one and
+	  // vice versa.
+	  function replaceInternalStreamId(pc, description) {
+	    let sdp = description.sdp;
+	    Object.keys(pc._reverseStreams || []).forEach(internalId => {
+	      const externalStream = pc._reverseStreams[internalId];
+	      const internalStream = pc._streams[externalStream.id];
+	      sdp = sdp.replace(new RegExp(internalStream.id, 'g'),
+	          externalStream.id);
+	    });
+	    return new RTCSessionDescription({
+	      type: description.type,
+	      sdp
+	    });
+	  }
+	  function replaceExternalStreamId(pc, description) {
+	    let sdp = description.sdp;
+	    Object.keys(pc._reverseStreams || []).forEach(internalId => {
+	      const externalStream = pc._reverseStreams[internalId];
+	      const internalStream = pc._streams[externalStream.id];
+	      sdp = sdp.replace(new RegExp(externalStream.id, 'g'),
+	          internalStream.id);
+	    });
+	    return new RTCSessionDescription({
+	      type: description.type,
+	      sdp
+	    });
+	  }
+	  ['createOffer', 'createAnswer'].forEach(function(method) {
+	    const nativeMethod = window.RTCPeerConnection.prototype[method];
+	    const methodObj = {[method]() {
+	      const args = arguments;
+	      const isLegacyCall = arguments.length &&
+	          typeof arguments[0] === 'function';
+	      if (isLegacyCall) {
+	        return nativeMethod.apply(this, [
+	          (description) => {
+	            const desc = replaceInternalStreamId(this, description);
+	            args[0].apply(null, [desc]);
+	          },
+	          (err) => {
+	            if (args[1]) {
+	              args[1].apply(null, err);
+	            }
+	          }, arguments[2]
+	        ]);
+	      }
+	      return nativeMethod.apply(this, arguments)
+	      .then(description => replaceInternalStreamId(this, description));
+	    }};
+	    window.RTCPeerConnection.prototype[method] = methodObj[method];
+	  });
+
+	  const origSetLocalDescription =
+	      window.RTCPeerConnection.prototype.setLocalDescription;
+	  window.RTCPeerConnection.prototype.setLocalDescription =
+	    function setLocalDescription() {
+	      if (!arguments.length || !arguments[0].type) {
+	        return origSetLocalDescription.apply(this, arguments);
+	      }
+	      arguments[0] = replaceExternalStreamId(this, arguments[0]);
+	      return origSetLocalDescription.apply(this, arguments);
+	    };
+
+	  // TODO: mangle getStats: https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamstats-streamidentifier
+
+	  const origLocalDescription = Object.getOwnPropertyDescriptor(
+	      window.RTCPeerConnection.prototype, 'localDescription');
+	  Object.defineProperty(window.RTCPeerConnection.prototype,
+	      'localDescription', {
+	        get() {
+	          const description = origLocalDescription.get.apply(this);
+	          if (description.type === '') {
+	            return description;
+	          }
+	          return replaceInternalStreamId(this, description);
+	        }
+	      });
+
+	  window.RTCPeerConnection.prototype.removeTrack =
+	    function removeTrack(sender) {
+	      if (this.signalingState === 'closed') {
+	        throw new DOMException(
+	          'The RTCPeerConnection\'s signalingState is \'closed\'.',
+	          'InvalidStateError');
+	      }
+	      // We can not yet check for sender instanceof RTCRtpSender
+	      // since we shim RTPSender. So we check if sender._pc is set.
+	      if (!sender._pc) {
+	        throw new DOMException('Argument 1 of RTCPeerConnection.removeTrack ' +
+	            'does not implement interface RTCRtpSender.', 'TypeError');
+	      }
+	      const isLocal = sender._pc === this;
+	      if (!isLocal) {
+	        throw new DOMException('Sender was not created by this connection.',
+	            'InvalidAccessError');
+	      }
+
+	      // Search for the native stream the senders track belongs to.
+	      this._streams = this._streams || {};
+	      let stream;
+	      Object.keys(this._streams).forEach(streamid => {
+	        const hasTrack = this._streams[streamid].getTracks()
+	          .find(track => sender.track === track);
+	        if (hasTrack) {
+	          stream = this._streams[streamid];
+	        }
+	      });
+
+	      if (stream) {
+	        if (stream.getTracks().length === 1) {
+	          // if this is the last track of the stream, remove the stream. This
+	          // takes care of any shimmed _senders.
+	          this.removeStream(this._reverseStreams[stream.id]);
+	        } else {
+	          // relying on the same odd chrome behaviour as above.
+	          stream.removeTrack(sender.track);
+	        }
+	        this.dispatchEvent(new Event('negotiationneeded'));
+	      }
+	    };
+	}
+
+	function shimPeerConnection$2(window, browserDetails) {
+	  if (!window.RTCPeerConnection && window.webkitRTCPeerConnection) {
+	    // very basic support for old versions.
+	    window.RTCPeerConnection = window.webkitRTCPeerConnection;
+	  }
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+
+	  // shim implicit creation of RTCSessionDescription/RTCIceCandidate
+	  if (browserDetails.version < 53) {
+	    ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
+	        .forEach(function(method) {
+	          const nativeMethod = window.RTCPeerConnection.prototype[method];
+	          const methodObj = {[method]() {
+	            arguments[0] = new ((method === 'addIceCandidate') ?
+	                window.RTCIceCandidate :
+	                window.RTCSessionDescription)(arguments[0]);
+	            return nativeMethod.apply(this, arguments);
+	          }};
+	          window.RTCPeerConnection.prototype[method] = methodObj[method];
+	        });
+	  }
+	}
+
+	// Attempt to fix ONN in plan-b mode.
+	function fixNegotiationNeeded(window, browserDetails) {
+	  wrapPeerConnectionEvent(window, 'negotiationneeded', e => {
+	    const pc = e.target;
+	    if (browserDetails.version < 72 || (pc.getConfiguration &&
+	        pc.getConfiguration().sdpSemantics === 'plan-b')) {
+	      if (pc.signalingState !== 'stable') {
+	        return;
+	      }
+	    }
+	    return e;
+	  });
+	}
+
+	var chromeShim = /*#__PURE__*/Object.freeze({
+		__proto__: null,
+		shimMediaStream: shimMediaStream,
+		shimOnTrack: shimOnTrack$1,
+		shimGetSendersWithDtmf: shimGetSendersWithDtmf,
+		shimGetStats: shimGetStats,
+		shimSenderReceiverGetStats: shimSenderReceiverGetStats,
+		shimAddTrackRemoveTrackWithNative: shimAddTrackRemoveTrackWithNative,
+		shimAddTrackRemoveTrack: shimAddTrackRemoveTrack,
+		shimPeerConnection: shimPeerConnection$2,
+		fixNegotiationNeeded: fixNegotiationNeeded,
+		shimGetUserMedia: shimGetUserMedia$3,
+		shimGetDisplayMedia: shimGetDisplayMedia$2
+	});
+
+	/*
+	 *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+	// Edge does not like
+	// 1) stun: filtered after 14393 unless ?transport=udp is present
+	// 2) turn: that does not have all of turn:host:port?transport=udp
+	// 3) turn: with ipv6 addresses
+	// 4) turn: occurring muliple times
+	function filterIceServers$1(iceServers, edgeVersion) {
+	  let hasTurn = false;
+	  iceServers = JSON.parse(JSON.stringify(iceServers));
+	  return iceServers.filter(server => {
+	    if (server && (server.urls || server.url)) {
+	      let urls = server.urls || server.url;
+	      if (server.url && !server.urls) {
+	        deprecated('RTCIceServer.url', 'RTCIceServer.urls');
+	      }
+	      const isString = typeof urls === 'string';
+	      if (isString) {
+	        urls = [urls];
+	      }
+	      urls = urls.filter(url => {
+	        // filter STUN unconditionally.
+	        if (url.indexOf('stun:') === 0) {
+	          return false;
+	        }
+
+	        const validTurn = url.startsWith('turn') &&
+	            !url.startsWith('turn:[') &&
+	            url.includes('transport=udp');
+	        if (validTurn && !hasTurn) {
+	          hasTurn = true;
+	          return true;
+	        }
+	        return validTurn && !hasTurn;
+	      });
+
+	      delete server.url;
+	      server.urls = isString ? urls[0] : urls;
+	      return !!urls.length;
+	    }
+	  });
+	}
+
+	function createCommonjsModule(fn) {
+	  var module = { exports: {} };
+		return fn(module, module.exports), module.exports;
+	}
+
+	/* eslint-env node */
+
+	var sdp = createCommonjsModule(function (module) {
+
+	// SDP helpers.
+	var SDPUtils = {};
+
+	// Generate an alphanumeric identifier for cname or mids.
+	// TODO: use UUIDs instead? https://gist.github.com/jed/982883
+	SDPUtils.generateIdentifier = function() {
+	  return Math.random().toString(36).substr(2, 10);
+	};
+
+	// The RTCP CNAME used by all peerconnections from the same JS.
+	SDPUtils.localCName = SDPUtils.generateIdentifier();
+
+	// Splits SDP into lines, dealing with both CRLF and LF.
+	SDPUtils.splitLines = function(blob) {
+	  return blob.trim().split('\n').map(function(line) {
+	    return line.trim();
+	  });
+	};
+	// Splits SDP into sessionpart and mediasections. Ensures CRLF.
+	SDPUtils.splitSections = function(blob) {
+	  var parts = blob.split('\nm=');
+	  return parts.map(function(part, index) {
+	    return (index > 0 ? 'm=' + part : part).trim() + '\r\n';
+	  });
+	};
+
+	// returns the session description.
+	SDPUtils.getDescription = function(blob) {
+	  var sections = SDPUtils.splitSections(blob);
+	  return sections && sections[0];
+	};
+
+	// returns the individual media sections.
+	SDPUtils.getMediaSections = function(blob) {
+	  var sections = SDPUtils.splitSections(blob);
+	  sections.shift();
+	  return sections;
+	};
+
+	// Returns lines that start with a certain prefix.
+	SDPUtils.matchPrefix = function(blob, prefix) {
+	  return SDPUtils.splitLines(blob).filter(function(line) {
+	    return line.indexOf(prefix) === 0;
+	  });
+	};
+
+	// Parses an ICE candidate line. Sample input:
+	// candidate:702786350 2 udp 41819902 8.8.8.8 60769 typ relay raddr 8.8.8.8
+	// rport 55996"
+	SDPUtils.parseCandidate = function(line) {
+	  var parts;
+	  // Parse both variants.
+	  if (line.indexOf('a=candidate:') === 0) {
+	    parts = line.substring(12).split(' ');
+	  } else {
+	    parts = line.substring(10).split(' ');
+	  }
+
+	  var candidate = {
+	    foundation: parts[0],
+	    component: parseInt(parts[1], 10),
+	    protocol: parts[2].toLowerCase(),
+	    priority: parseInt(parts[3], 10),
+	    ip: parts[4],
+	    address: parts[4], // address is an alias for ip.
+	    port: parseInt(parts[5], 10),
+	    // skip parts[6] == 'typ'
+	    type: parts[7]
+	  };
+
+	  for (var i = 8; i < parts.length; i += 2) {
+	    switch (parts[i]) {
+	      case 'raddr':
+	        candidate.relatedAddress = parts[i + 1];
+	        break;
+	      case 'rport':
+	        candidate.relatedPort = parseInt(parts[i + 1], 10);
+	        break;
+	      case 'tcptype':
+	        candidate.tcpType = parts[i + 1];
+	        break;
+	      case 'ufrag':
+	        candidate.ufrag = parts[i + 1]; // for backward compability.
+	        candidate.usernameFragment = parts[i + 1];
+	        break;
+	      default: // extension handling, in particular ufrag
+	        candidate[parts[i]] = parts[i + 1];
+	        break;
+	    }
+	  }
+	  return candidate;
+	};
+
+	// Translates a candidate object into SDP candidate attribute.
+	SDPUtils.writeCandidate = function(candidate) {
+	  var sdp = [];
+	  sdp.push(candidate.foundation);
+	  sdp.push(candidate.component);
+	  sdp.push(candidate.protocol.toUpperCase());
+	  sdp.push(candidate.priority);
+	  sdp.push(candidate.address || candidate.ip);
+	  sdp.push(candidate.port);
+
+	  var type = candidate.type;
+	  sdp.push('typ');
+	  sdp.push(type);
+	  if (type !== 'host' && candidate.relatedAddress &&
+	      candidate.relatedPort) {
+	    sdp.push('raddr');
+	    sdp.push(candidate.relatedAddress);
+	    sdp.push('rport');
+	    sdp.push(candidate.relatedPort);
+	  }
+	  if (candidate.tcpType && candidate.protocol.toLowerCase() === 'tcp') {
+	    sdp.push('tcptype');
+	    sdp.push(candidate.tcpType);
+	  }
+	  if (candidate.usernameFragment || candidate.ufrag) {
+	    sdp.push('ufrag');
+	    sdp.push(candidate.usernameFragment || candidate.ufrag);
+	  }
+	  return 'candidate:' + sdp.join(' ');
+	};
+
+	// Parses an ice-options line, returns an array of option tags.
+	// a=ice-options:foo bar
+	SDPUtils.parseIceOptions = function(line) {
+	  return line.substr(14).split(' ');
+	};
+
+	// Parses an rtpmap line, returns RTCRtpCoddecParameters. Sample input:
+	// a=rtpmap:111 opus/48000/2
+	SDPUtils.parseRtpMap = function(line) {
+	  var parts = line.substr(9).split(' ');
+	  var parsed = {
+	    payloadType: parseInt(parts.shift(), 10) // was: id
+	  };
+
+	  parts = parts[0].split('/');
+
+	  parsed.name = parts[0];
+	  parsed.clockRate = parseInt(parts[1], 10); // was: clockrate
+	  parsed.channels = parts.length === 3 ? parseInt(parts[2], 10) : 1;
+	  // legacy alias, got renamed back to channels in ORTC.
+	  parsed.numChannels = parsed.channels;
+	  return parsed;
+	};
+
+	// Generate an a=rtpmap line from RTCRtpCodecCapability or
+	// RTCRtpCodecParameters.
+	SDPUtils.writeRtpMap = function(codec) {
+	  var pt = codec.payloadType;
+	  if (codec.preferredPayloadType !== undefined) {
+	    pt = codec.preferredPayloadType;
+	  }
+	  var channels = codec.channels || codec.numChannels || 1;
+	  return 'a=rtpmap:' + pt + ' ' + codec.name + '/' + codec.clockRate +
+	      (channels !== 1 ? '/' + channels : '') + '\r\n';
+	};
+
+	// Parses an a=extmap line (headerextension from RFC 5285). Sample input:
+	// a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
+	// a=extmap:2/sendonly urn:ietf:params:rtp-hdrext:toffset
+	SDPUtils.parseExtmap = function(line) {
+	  var parts = line.substr(9).split(' ');
+	  return {
+	    id: parseInt(parts[0], 10),
+	    direction: parts[0].indexOf('/') > 0 ? parts[0].split('/')[1] : 'sendrecv',
+	    uri: parts[1]
+	  };
+	};
+
+	// Generates a=extmap line from RTCRtpHeaderExtensionParameters or
+	// RTCRtpHeaderExtension.
+	SDPUtils.writeExtmap = function(headerExtension) {
+	  return 'a=extmap:' + (headerExtension.id || headerExtension.preferredId) +
+	      (headerExtension.direction && headerExtension.direction !== 'sendrecv'
+	        ? '/' + headerExtension.direction
+	        : '') +
+	      ' ' + headerExtension.uri + '\r\n';
+	};
+
+	// Parses an ftmp line, returns dictionary. Sample input:
+	// a=fmtp:96 vbr=on;cng=on
+	// Also deals with vbr=on; cng=on
+	SDPUtils.parseFmtp = function(line) {
+	  var parsed = {};
+	  var kv;
+	  var parts = line.substr(line.indexOf(' ') + 1).split(';');
+	  for (var j = 0; j < parts.length; j++) {
+	    kv = parts[j].trim().split('=');
+	    parsed[kv[0].trim()] = kv[1];
+	  }
+	  return parsed;
+	};
+
+	// Generates an a=ftmp line from RTCRtpCodecCapability or RTCRtpCodecParameters.
+	SDPUtils.writeFmtp = function(codec) {
+	  var line = '';
+	  var pt = codec.payloadType;
+	  if (codec.preferredPayloadType !== undefined) {
+	    pt = codec.preferredPayloadType;
+	  }
+	  if (codec.parameters && Object.keys(codec.parameters).length) {
+	    var params = [];
+	    Object.keys(codec.parameters).forEach(function(param) {
+	      if (codec.parameters[param]) {
+	        params.push(param + '=' + codec.parameters[param]);
+	      } else {
+	        params.push(param);
+	      }
+	    });
+	    line += 'a=fmtp:' + pt + ' ' + params.join(';') + '\r\n';
+	  }
+	  return line;
+	};
+
+	// Parses an rtcp-fb line, returns RTCPRtcpFeedback object. Sample input:
+	// a=rtcp-fb:98 nack rpsi
+	SDPUtils.parseRtcpFb = function(line) {
+	  var parts = line.substr(line.indexOf(' ') + 1).split(' ');
+	  return {
+	    type: parts.shift(),
+	    parameter: parts.join(' ')
+	  };
+	};
+	// Generate a=rtcp-fb lines from RTCRtpCodecCapability or RTCRtpCodecParameters.
+	SDPUtils.writeRtcpFb = function(codec) {
+	  var lines = '';
+	  var pt = codec.payloadType;
+	  if (codec.preferredPayloadType !== undefined) {
+	    pt = codec.preferredPayloadType;
+	  }
+	  if (codec.rtcpFeedback && codec.rtcpFeedback.length) {
+	    // FIXME: special handling for trr-int?
+	    codec.rtcpFeedback.forEach(function(fb) {
+	      lines += 'a=rtcp-fb:' + pt + ' ' + fb.type +
+	      (fb.parameter && fb.parameter.length ? ' ' + fb.parameter : '') +
+	          '\r\n';
+	    });
+	  }
+	  return lines;
+	};
+
+	// Parses an RFC 5576 ssrc media attribute. Sample input:
+	// a=ssrc:3735928559 cname:something
+	SDPUtils.parseSsrcMedia = function(line) {
+	  var sp = line.indexOf(' ');
+	  var parts = {
+	    ssrc: parseInt(line.substr(7, sp - 7), 10)
+	  };
+	  var colon = line.indexOf(':', sp);
+	  if (colon > -1) {
+	    parts.attribute = line.substr(sp + 1, colon - sp - 1);
+	    parts.value = line.substr(colon + 1);
+	  } else {
+	    parts.attribute = line.substr(sp + 1);
+	  }
+	  return parts;
+	};
+
+	SDPUtils.parseSsrcGroup = function(line) {
+	  var parts = line.substr(13).split(' ');
+	  return {
+	    semantics: parts.shift(),
+	    ssrcs: parts.map(function(ssrc) {
+	      return parseInt(ssrc, 10);
+	    })
+	  };
+	};
+
+	// Extracts the MID (RFC 5888) from a media section.
+	// returns the MID or undefined if no mid line was found.
+	SDPUtils.getMid = function(mediaSection) {
+	  var mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:')[0];
+	  if (mid) {
+	    return mid.substr(6);
+	  }
+	};
+
+	SDPUtils.parseFingerprint = function(line) {
+	  var parts = line.substr(14).split(' ');
+	  return {
+	    algorithm: parts[0].toLowerCase(), // algorithm is case-sensitive in Edge.
+	    value: parts[1]
+	  };
+	};
+
+	// Extracts DTLS parameters from SDP media section or sessionpart.
+	// FIXME: for consistency with other functions this should only
+	//   get the fingerprint line as input. See also getIceParameters.
+	SDPUtils.getDtlsParameters = function(mediaSection, sessionpart) {
+	  var lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
+	    'a=fingerprint:');
+	  // Note: a=setup line is ignored since we use the 'auto' role.
+	  // Note2: 'algorithm' is not case sensitive except in Edge.
+	  return {
+	    role: 'auto',
+	    fingerprints: lines.map(SDPUtils.parseFingerprint)
+	  };
+	};
+
+	// Serializes DTLS parameters to SDP.
+	SDPUtils.writeDtlsParameters = function(params, setupType) {
+	  var sdp = 'a=setup:' + setupType + '\r\n';
+	  params.fingerprints.forEach(function(fp) {
+	    sdp += 'a=fingerprint:' + fp.algorithm + ' ' + fp.value + '\r\n';
+	  });
+	  return sdp;
+	};
+
+	// Parses a=crypto lines into
+	//   https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#dictionary-rtcsrtpsdesparameters-members
+	SDPUtils.parseCryptoLine = function(line) {
+	  var parts = line.substr(9).split(' ');
+	  return {
+	    tag: parseInt(parts[0], 10),
+	    cryptoSuite: parts[1],
+	    keyParams: parts[2],
+	    sessionParams: parts.slice(3),
+	  };
+	};
+
+	SDPUtils.writeCryptoLine = function(parameters) {
+	  return 'a=crypto:' + parameters.tag + ' ' +
+	    parameters.cryptoSuite + ' ' +
+	    (typeof parameters.keyParams === 'object'
+	      ? SDPUtils.writeCryptoKeyParams(parameters.keyParams)
+	      : parameters.keyParams) +
+	    (parameters.sessionParams ? ' ' + parameters.sessionParams.join(' ') : '') +
+	    '\r\n';
+	};
+
+	// Parses the crypto key parameters into
+	//   https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#rtcsrtpkeyparam*
+	SDPUtils.parseCryptoKeyParams = function(keyParams) {
+	  if (keyParams.indexOf('inline:') !== 0) {
+	    return null;
+	  }
+	  var parts = keyParams.substr(7).split('|');
+	  return {
+	    keyMethod: 'inline',
+	    keySalt: parts[0],
+	    lifeTime: parts[1],
+	    mkiValue: parts[2] ? parts[2].split(':')[0] : undefined,
+	    mkiLength: parts[2] ? parts[2].split(':')[1] : undefined,
+	  };
+	};
+
+	SDPUtils.writeCryptoKeyParams = function(keyParams) {
+	  return keyParams.keyMethod + ':'
+	    + keyParams.keySalt +
+	    (keyParams.lifeTime ? '|' + keyParams.lifeTime : '') +
+	    (keyParams.mkiValue && keyParams.mkiLength
+	      ? '|' + keyParams.mkiValue + ':' + keyParams.mkiLength
+	      : '');
+	};
+
+	// Extracts all SDES paramters.
+	SDPUtils.getCryptoParameters = function(mediaSection, sessionpart) {
+	  var lines = SDPUtils.matchPrefix(mediaSection + sessionpart,
+	    'a=crypto:');
+	  return lines.map(SDPUtils.parseCryptoLine);
+	};
+
+	// Parses ICE information from SDP media section or sessionpart.
+	// FIXME: for consistency with other functions this should only
+	//   get the ice-ufrag and ice-pwd lines as input.
+	SDPUtils.getIceParameters = function(mediaSection, sessionpart) {
+	  var ufrag = SDPUtils.matchPrefix(mediaSection + sessionpart,
+	    'a=ice-ufrag:')[0];
+	  var pwd = SDPUtils.matchPrefix(mediaSection + sessionpart,
+	    'a=ice-pwd:')[0];
+	  if (!(ufrag && pwd)) {
+	    return null;
+	  }
+	  return {
+	    usernameFragment: ufrag.substr(12),
+	    password: pwd.substr(10),
+	  };
+	};
+
+	// Serializes ICE parameters to SDP.
+	SDPUtils.writeIceParameters = function(params) {
+	  return 'a=ice-ufrag:' + params.usernameFragment + '\r\n' +
+	      'a=ice-pwd:' + params.password + '\r\n';
+	};
+
+	// Parses the SDP media section and returns RTCRtpParameters.
+	SDPUtils.parseRtpParameters = function(mediaSection) {
+	  var description = {
+	    codecs: [],
+	    headerExtensions: [],
+	    fecMechanisms: [],
+	    rtcp: []
+	  };
+	  var lines = SDPUtils.splitLines(mediaSection);
+	  var mline = lines[0].split(' ');
+	  for (var i = 3; i < mline.length; i++) { // find all codecs from mline[3..]
+	    var pt = mline[i];
+	    var rtpmapline = SDPUtils.matchPrefix(
+	      mediaSection, 'a=rtpmap:' + pt + ' ')[0];
+	    if (rtpmapline) {
+	      var codec = SDPUtils.parseRtpMap(rtpmapline);
+	      var fmtps = SDPUtils.matchPrefix(
+	        mediaSection, 'a=fmtp:' + pt + ' ');
+	      // Only the first a=fmtp:<pt> is considered.
+	      codec.parameters = fmtps.length ? SDPUtils.parseFmtp(fmtps[0]) : {};
+	      codec.rtcpFeedback = SDPUtils.matchPrefix(
+	        mediaSection, 'a=rtcp-fb:' + pt + ' ')
+	        .map(SDPUtils.parseRtcpFb);
+	      description.codecs.push(codec);
+	      // parse FEC mechanisms from rtpmap lines.
+	      switch (codec.name.toUpperCase()) {
+	        case 'RED':
+	        case 'ULPFEC':
+	          description.fecMechanisms.push(codec.name.toUpperCase());
+	          break;
+	      }
+	    }
+	  }
+	  SDPUtils.matchPrefix(mediaSection, 'a=extmap:').forEach(function(line) {
+	    description.headerExtensions.push(SDPUtils.parseExtmap(line));
+	  });
+	  // FIXME: parse rtcp.
+	  return description;
+	};
+
+	// Generates parts of the SDP media section describing the capabilities /
+	// parameters.
+	SDPUtils.writeRtpDescription = function(kind, caps) {
+	  var sdp = '';
+
+	  // Build the mline.
+	  sdp += 'm=' + kind + ' ';
+	  sdp += caps.codecs.length > 0 ? '9' : '0'; // reject if no codecs.
+	  sdp += ' UDP/TLS/RTP/SAVPF ';
+	  sdp += caps.codecs.map(function(codec) {
+	    if (codec.preferredPayloadType !== undefined) {
+	      return codec.preferredPayloadType;
+	    }
+	    return codec.payloadType;
+	  }).join(' ') + '\r\n';
+
+	  sdp += 'c=IN IP4 0.0.0.0\r\n';
+	  sdp += 'a=rtcp:9 IN IP4 0.0.0.0\r\n';
+
+	  // Add a=rtpmap lines for each codec. Also fmtp and rtcp-fb.
+	  caps.codecs.forEach(function(codec) {
+	    sdp += SDPUtils.writeRtpMap(codec);
+	    sdp += SDPUtils.writeFmtp(codec);
+	    sdp += SDPUtils.writeRtcpFb(codec);
+	  });
+	  var maxptime = 0;
+	  caps.codecs.forEach(function(codec) {
+	    if (codec.maxptime > maxptime) {
+	      maxptime = codec.maxptime;
+	    }
+	  });
+	  if (maxptime > 0) {
+	    sdp += 'a=maxptime:' + maxptime + '\r\n';
+	  }
+	  sdp += 'a=rtcp-mux\r\n';
+
+	  if (caps.headerExtensions) {
+	    caps.headerExtensions.forEach(function(extension) {
+	      sdp += SDPUtils.writeExtmap(extension);
+	    });
+	  }
+	  // FIXME: write fecMechanisms.
+	  return sdp;
+	};
+
+	// Parses the SDP media section and returns an array of
+	// RTCRtpEncodingParameters.
+	SDPUtils.parseRtpEncodingParameters = function(mediaSection) {
+	  var encodingParameters = [];
+	  var description = SDPUtils.parseRtpParameters(mediaSection);
+	  var hasRed = description.fecMechanisms.indexOf('RED') !== -1;
+	  var hasUlpfec = description.fecMechanisms.indexOf('ULPFEC') !== -1;
+
+	  // filter a=ssrc:... cname:, ignore PlanB-msid
+	  var ssrcs = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
+	    .map(function(line) {
+	      return SDPUtils.parseSsrcMedia(line);
+	    })
+	    .filter(function(parts) {
+	      return parts.attribute === 'cname';
+	    });
+	  var primarySsrc = ssrcs.length > 0 && ssrcs[0].ssrc;
+	  var secondarySsrc;
+
+	  var flows = SDPUtils.matchPrefix(mediaSection, 'a=ssrc-group:FID')
+	    .map(function(line) {
+	      var parts = line.substr(17).split(' ');
+	      return parts.map(function(part) {
+	        return parseInt(part, 10);
+	      });
+	    });
+	  if (flows.length > 0 && flows[0].length > 1 && flows[0][0] === primarySsrc) {
+	    secondarySsrc = flows[0][1];
+	  }
+
+	  description.codecs.forEach(function(codec) {
+	    if (codec.name.toUpperCase() === 'RTX' && codec.parameters.apt) {
+	      var encParam = {
+	        ssrc: primarySsrc,
+	        codecPayloadType: parseInt(codec.parameters.apt, 10)
+	      };
+	      if (primarySsrc && secondarySsrc) {
+	        encParam.rtx = {ssrc: secondarySsrc};
+	      }
+	      encodingParameters.push(encParam);
+	      if (hasRed) {
+	        encParam = JSON.parse(JSON.stringify(encParam));
+	        encParam.fec = {
+	          ssrc: primarySsrc,
+	          mechanism: hasUlpfec ? 'red+ulpfec' : 'red'
+	        };
+	        encodingParameters.push(encParam);
+	      }
+	    }
+	  });
+	  if (encodingParameters.length === 0 && primarySsrc) {
+	    encodingParameters.push({
+	      ssrc: primarySsrc
+	    });
+	  }
+
+	  // we support both b=AS and b=TIAS but interpret AS as TIAS.
+	  var bandwidth = SDPUtils.matchPrefix(mediaSection, 'b=');
+	  if (bandwidth.length) {
+	    if (bandwidth[0].indexOf('b=TIAS:') === 0) {
+	      bandwidth = parseInt(bandwidth[0].substr(7), 10);
+	    } else if (bandwidth[0].indexOf('b=AS:') === 0) {
+	      // use formula from JSEP to convert b=AS to TIAS value.
+	      bandwidth = parseInt(bandwidth[0].substr(5), 10) * 1000 * 0.95
+	          - (50 * 40 * 8);
+	    } else {
+	      bandwidth = undefined;
+	    }
+	    encodingParameters.forEach(function(params) {
+	      params.maxBitrate = bandwidth;
+	    });
+	  }
+	  return encodingParameters;
+	};
+
+	// parses http://draft.ortc.org/#rtcrtcpparameters*
+	SDPUtils.parseRtcpParameters = function(mediaSection) {
+	  var rtcpParameters = {};
+
+	  // Gets the first SSRC. Note tha with RTX there might be multiple
+	  // SSRCs.
+	  var remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
+	    .map(function(line) {
+	      return SDPUtils.parseSsrcMedia(line);
+	    })
+	    .filter(function(obj) {
+	      return obj.attribute === 'cname';
+	    })[0];
+	  if (remoteSsrc) {
+	    rtcpParameters.cname = remoteSsrc.value;
+	    rtcpParameters.ssrc = remoteSsrc.ssrc;
+	  }
+
+	  // Edge uses the compound attribute instead of reducedSize
+	  // compound is !reducedSize
+	  var rsize = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-rsize');
+	  rtcpParameters.reducedSize = rsize.length > 0;
+	  rtcpParameters.compound = rsize.length === 0;
+
+	  // parses the rtcp-mux attrіbute.
+	  // Note that Edge does not support unmuxed RTCP.
+	  var mux = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-mux');
+	  rtcpParameters.mux = mux.length > 0;
+
+	  return rtcpParameters;
+	};
+
+	// parses either a=msid: or a=ssrc:... msid lines and returns
+	// the id of the MediaStream and MediaStreamTrack.
+	SDPUtils.parseMsid = function(mediaSection) {
+	  var parts;
+	  var spec = SDPUtils.matchPrefix(mediaSection, 'a=msid:');
+	  if (spec.length === 1) {
+	    parts = spec[0].substr(7).split(' ');
+	    return {stream: parts[0], track: parts[1]};
+	  }
+	  var planB = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
+	    .map(function(line) {
+	      return SDPUtils.parseSsrcMedia(line);
+	    })
+	    .filter(function(msidParts) {
+	      return msidParts.attribute === 'msid';
+	    });
+	  if (planB.length > 0) {
+	    parts = planB[0].value.split(' ');
+	    return {stream: parts[0], track: parts[1]};
+	  }
+	};
+
+	// SCTP
+	// parses draft-ietf-mmusic-sctp-sdp-26 first and falls back
+	// to draft-ietf-mmusic-sctp-sdp-05
+	SDPUtils.parseSctpDescription = function(mediaSection) {
+	  var mline = SDPUtils.parseMLine(mediaSection);
+	  var maxSizeLine = SDPUtils.matchPrefix(mediaSection, 'a=max-message-size:');
+	  var maxMessageSize;
+	  if (maxSizeLine.length > 0) {
+	    maxMessageSize = parseInt(maxSizeLine[0].substr(19), 10);
+	  }
+	  if (isNaN(maxMessageSize)) {
+	    maxMessageSize = 65536;
+	  }
+	  var sctpPort = SDPUtils.matchPrefix(mediaSection, 'a=sctp-port:');
+	  if (sctpPort.length > 0) {
+	    return {
+	      port: parseInt(sctpPort[0].substr(12), 10),
+	      protocol: mline.fmt,
+	      maxMessageSize: maxMessageSize
+	    };
+	  }
+	  var sctpMapLines = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:');
+	  if (sctpMapLines.length > 0) {
+	    var parts = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:')[0]
+	      .substr(10)
+	      .split(' ');
+	    return {
+	      port: parseInt(parts[0], 10),
+	      protocol: parts[1],
+	      maxMessageSize: maxMessageSize
+	    };
+	  }
+	};
+
+	// SCTP
+	// outputs the draft-ietf-mmusic-sctp-sdp-26 version that all browsers
+	// support by now receiving in this format, unless we originally parsed
+	// as the draft-ietf-mmusic-sctp-sdp-05 format (indicated by the m-line
+	// protocol of DTLS/SCTP -- without UDP/ or TCP/)
+	SDPUtils.writeSctpDescription = function(media, sctp) {
+	  var output = [];
+	  if (media.protocol !== 'DTLS/SCTP') {
+	    output = [
+	      'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.protocol + '\r\n',
+	      'c=IN IP4 0.0.0.0\r\n',
+	      'a=sctp-port:' + sctp.port + '\r\n'
+	    ];
+	  } else {
+	    output = [
+	      'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.port + '\r\n',
+	      'c=IN IP4 0.0.0.0\r\n',
+	      'a=sctpmap:' + sctp.port + ' ' + sctp.protocol + ' 65535\r\n'
+	    ];
+	  }
+	  if (sctp.maxMessageSize !== undefined) {
+	    output.push('a=max-message-size:' + sctp.maxMessageSize + '\r\n');
+	  }
+	  return output.join('');
+	};
+
+	// Generate a session ID for SDP.
+	// https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-20#section-5.2.1
+	// recommends using a cryptographically random +ve 64-bit value
+	// but right now this should be acceptable and within the right range
+	SDPUtils.generateSessionId = function() {
+	  return Math.random().toString().substr(2, 21);
+	};
+
+	// Write boilder plate for start of SDP
+	// sessId argument is optional - if not supplied it will
+	// be generated randomly
+	// sessVersion is optional and defaults to 2
+	// sessUser is optional and defaults to 'thisisadapterortc'
+	SDPUtils.writeSessionBoilerplate = function(sessId, sessVer, sessUser) {
+	  var sessionId;
+	  var version = sessVer !== undefined ? sessVer : 2;
+	  if (sessId) {
+	    sessionId = sessId;
+	  } else {
+	    sessionId = SDPUtils.generateSessionId();
+	  }
+	  var user = sessUser || 'thisisadapterortc';
+	  // FIXME: sess-id should be an NTP timestamp.
+	  return 'v=0\r\n' +
+	      'o=' + user + ' ' + sessionId + ' ' + version +
+	        ' IN IP4 127.0.0.1\r\n' +
+	      's=-\r\n' +
+	      't=0 0\r\n';
+	};
+
+	SDPUtils.writeMediaSection = function(transceiver, caps, type, stream) {
+	  var sdp = SDPUtils.writeRtpDescription(transceiver.kind, caps);
+
+	  // Map ICE parameters (ufrag, pwd) to SDP.
+	  sdp += SDPUtils.writeIceParameters(
+	    transceiver.iceGatherer.getLocalParameters());
+
+	  // Map DTLS parameters to SDP.
+	  sdp += SDPUtils.writeDtlsParameters(
+	    transceiver.dtlsTransport.getLocalParameters(),
+	    type === 'offer' ? 'actpass' : 'active');
+
+	  sdp += 'a=mid:' + transceiver.mid + '\r\n';
+
+	  if (transceiver.direction) {
+	    sdp += 'a=' + transceiver.direction + '\r\n';
+	  } else if (transceiver.rtpSender && transceiver.rtpReceiver) {
+	    sdp += 'a=sendrecv\r\n';
+	  } else if (transceiver.rtpSender) {
+	    sdp += 'a=sendonly\r\n';
+	  } else if (transceiver.rtpReceiver) {
+	    sdp += 'a=recvonly\r\n';
+	  } else {
+	    sdp += 'a=inactive\r\n';
+	  }
+
+	  if (transceiver.rtpSender) {
+	    // spec.
+	    var msid = 'msid:' + stream.id + ' ' +
+	        transceiver.rtpSender.track.id + '\r\n';
+	    sdp += 'a=' + msid;
+
+	    // for Chrome.
+	    sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
+	        ' ' + msid;
+	    if (transceiver.sendEncodingParameters[0].rtx) {
+	      sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
+	          ' ' + msid;
+	      sdp += 'a=ssrc-group:FID ' +
+	          transceiver.sendEncodingParameters[0].ssrc + ' ' +
+	          transceiver.sendEncodingParameters[0].rtx.ssrc +
+	          '\r\n';
+	    }
+	  }
+	  // FIXME: this should be written by writeRtpDescription.
+	  sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
+	      ' cname:' + SDPUtils.localCName + '\r\n';
+	  if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
+	    sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
+	        ' cname:' + SDPUtils.localCName + '\r\n';
+	  }
+	  return sdp;
+	};
+
+	// Gets the direction from the mediaSection or the sessionpart.
+	SDPUtils.getDirection = function(mediaSection, sessionpart) {
+	  // Look for sendrecv, sendonly, recvonly, inactive, default to sendrecv.
+	  var lines = SDPUtils.splitLines(mediaSection);
+	  for (var i = 0; i < lines.length; i++) {
+	    switch (lines[i]) {
+	      case 'a=sendrecv':
+	      case 'a=sendonly':
+	      case 'a=recvonly':
+	      case 'a=inactive':
+	        return lines[i].substr(2);
+	        // FIXME: What should happen here?
+	    }
+	  }
+	  if (sessionpart) {
+	    return SDPUtils.getDirection(sessionpart);
+	  }
+	  return 'sendrecv';
+	};
+
+	SDPUtils.getKind = function(mediaSection) {
+	  var lines = SDPUtils.splitLines(mediaSection);
+	  var mline = lines[0].split(' ');
+	  return mline[0].substr(2);
+	};
+
+	SDPUtils.isRejected = function(mediaSection) {
+	  return mediaSection.split(' ', 2)[1] === '0';
+	};
+
+	SDPUtils.parseMLine = function(mediaSection) {
+	  var lines = SDPUtils.splitLines(mediaSection);
+	  var parts = lines[0].substr(2).split(' ');
+	  return {
+	    kind: parts[0],
+	    port: parseInt(parts[1], 10),
+	    protocol: parts[2],
+	    fmt: parts.slice(3).join(' ')
+	  };
+	};
+
+	SDPUtils.parseOLine = function(mediaSection) {
+	  var line = SDPUtils.matchPrefix(mediaSection, 'o=')[0];
+	  var parts = line.substr(2).split(' ');
+	  return {
+	    username: parts[0],
+	    sessionId: parts[1],
+	    sessionVersion: parseInt(parts[2], 10),
+	    netType: parts[3],
+	    addressType: parts[4],
+	    address: parts[5]
+	  };
+	};
+
+	// a very naive interpretation of a valid SDP.
+	SDPUtils.isValidSDP = function(blob) {
+	  if (typeof blob !== 'string' || blob.length === 0) {
+	    return false;
+	  }
+	  var lines = SDPUtils.splitLines(blob);
+	  for (var i = 0; i < lines.length; i++) {
+	    if (lines[i].length < 2 || lines[i].charAt(1) !== '=') {
+	      return false;
+	    }
+	    // TODO: check the modifier a bit more.
+	  }
+	  return true;
+	};
+
+	// Expose public methods.
+	{
+	  module.exports = SDPUtils;
+	}
+	});
+
+	/*
+	 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+
+
+	function fixStatsType(stat) {
+	  return {
+	    inboundrtp: 'inbound-rtp',
+	    outboundrtp: 'outbound-rtp',
+	    candidatepair: 'candidate-pair',
+	    localcandidate: 'local-candidate',
+	    remotecandidate: 'remote-candidate'
+	  }[stat.type] || stat.type;
+	}
+
+	function writeMediaSection(transceiver, caps, type, stream, dtlsRole) {
+	  var sdp$1 = sdp.writeRtpDescription(transceiver.kind, caps);
+
+	  // Map ICE parameters (ufrag, pwd) to SDP.
+	  sdp$1 += sdp.writeIceParameters(
+	      transceiver.iceGatherer.getLocalParameters());
+
+	  // Map DTLS parameters to SDP.
+	  sdp$1 += sdp.writeDtlsParameters(
+	      transceiver.dtlsTransport.getLocalParameters(),
+	      type === 'offer' ? 'actpass' : dtlsRole || 'active');
+
+	  sdp$1 += 'a=mid:' + transceiver.mid + '\r\n';
+
+	  if (transceiver.rtpSender && transceiver.rtpReceiver) {
+	    sdp$1 += 'a=sendrecv\r\n';
+	  } else if (transceiver.rtpSender) {
+	    sdp$1 += 'a=sendonly\r\n';
+	  } else if (transceiver.rtpReceiver) {
+	    sdp$1 += 'a=recvonly\r\n';
+	  } else {
+	    sdp$1 += 'a=inactive\r\n';
+	  }
+
+	  if (transceiver.rtpSender) {
+	    var trackId = transceiver.rtpSender._initialTrackId ||
+	        transceiver.rtpSender.track.id;
+	    transceiver.rtpSender._initialTrackId = trackId;
+	    // spec.
+	    var msid = 'msid:' + (stream ? stream.id : '-') + ' ' +
+	        trackId + '\r\n';
+	    sdp$1 += 'a=' + msid;
+	    // for Chrome. Legacy should no longer be required.
+	    sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
+	        ' ' + msid;
+
+	    // RTX
+	    if (transceiver.sendEncodingParameters[0].rtx) {
+	      sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
+	          ' ' + msid;
+	      sdp$1 += 'a=ssrc-group:FID ' +
+	          transceiver.sendEncodingParameters[0].ssrc + ' ' +
+	          transceiver.sendEncodingParameters[0].rtx.ssrc +
+	          '\r\n';
+	    }
+	  }
+	  // FIXME: this should be written by writeRtpDescription.
+	  sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc +
+	      ' cname:' + sdp.localCName + '\r\n';
+	  if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
+	    sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc +
+	        ' cname:' + sdp.localCName + '\r\n';
+	  }
+	  return sdp$1;
+	}
+
+	// Edge does not like
+	// 1) stun: filtered after 14393 unless ?transport=udp is present
+	// 2) turn: that does not have all of turn:host:port?transport=udp
+	// 3) turn: with ipv6 addresses
+	// 4) turn: occurring muliple times
+	function filterIceServers(iceServers, edgeVersion) {
+	  var hasTurn = false;
+	  iceServers = JSON.parse(JSON.stringify(iceServers));
+	  return iceServers.filter(function(server) {
+	    if (server && (server.urls || server.url)) {
+	      var urls = server.urls || server.url;
+	      if (server.url && !server.urls) {
+	        console.warn('RTCIceServer.url is deprecated! Use urls instead.');
+	      }
+	      var isString = typeof urls === 'string';
+	      if (isString) {
+	        urls = [urls];
+	      }
+	      urls = urls.filter(function(url) {
+	        var validTurn = url.indexOf('turn:') === 0 &&
+	            url.indexOf('transport=udp') !== -1 &&
+	            url.indexOf('turn:[') === -1 &&
+	            !hasTurn;
+
+	        if (validTurn) {
+	          hasTurn = true;
+	          return true;
+	        }
+	        return url.indexOf('stun:') === 0 && edgeVersion >= 14393 &&
+	            url.indexOf('?transport=udp') === -1;
+	      });
+
+	      delete server.url;
+	      server.urls = isString ? urls[0] : urls;
+	      return !!urls.length;
+	    }
+	  });
+	}
+
+	// Determines the intersection of local and remote capabilities.
+	function getCommonCapabilities(localCapabilities, remoteCapabilities) {
+	  var commonCapabilities = {
+	    codecs: [],
+	    headerExtensions: [],
+	    fecMechanisms: []
+	  };
+
+	  var findCodecByPayloadType = function(pt, codecs) {
+	    pt = parseInt(pt, 10);
+	    for (var i = 0; i < codecs.length; i++) {
+	      if (codecs[i].payloadType === pt ||
+	          codecs[i].preferredPayloadType === pt) {
+	        return codecs[i];
+	      }
+	    }
+	  };
+
+	  var rtxCapabilityMatches = function(lRtx, rRtx, lCodecs, rCodecs) {
+	    var lCodec = findCodecByPayloadType(lRtx.parameters.apt, lCodecs);
+	    var rCodec = findCodecByPayloadType(rRtx.parameters.apt, rCodecs);
+	    return lCodec && rCodec &&
+	        lCodec.name.toLowerCase() === rCodec.name.toLowerCase();
+	  };
+
+	  localCapabilities.codecs.forEach(function(lCodec) {
+	    for (var i = 0; i < remoteCapabilities.codecs.length; i++) {
+	      var rCodec = remoteCapabilities.codecs[i];
+	      if (lCodec.name.toLowerCase() === rCodec.name.toLowerCase() &&
+	          lCodec.clockRate === rCodec.clockRate) {
+	        if (lCodec.name.toLowerCase() === 'rtx' &&
+	            lCodec.parameters && rCodec.parameters.apt) {
+	          // for RTX we need to find the local rtx that has a apt
+	          // which points to the same local codec as the remote one.
+	          if (!rtxCapabilityMatches(lCodec, rCodec,
+	              localCapabilities.codecs, remoteCapabilities.codecs)) {
+	            continue;
+	          }
+	        }
+	        rCodec = JSON.parse(JSON.stringify(rCodec)); // deepcopy
+	        // number of channels is the highest common number of channels
+	        rCodec.numChannels = Math.min(lCodec.numChannels,
+	            rCodec.numChannels);
+	        // push rCodec so we reply with offerer payload type
+	        commonCapabilities.codecs.push(rCodec);
+
+	        // determine common feedback mechanisms
+	        rCodec.rtcpFeedback = rCodec.rtcpFeedback.filter(function(fb) {
+	          for (var j = 0; j < lCodec.rtcpFeedback.length; j++) {
+	            if (lCodec.rtcpFeedback[j].type === fb.type &&
+	                lCodec.rtcpFeedback[j].parameter === fb.parameter) {
+	              return true;
+	            }
+	          }
+	          return false;
+	        });
+	        // FIXME: also need to determine .parameters
+	        //  see https://github.com/openpeer/ortc/issues/569
+	        break;
+	      }
+	    }
+	  });
+
+	  localCapabilities.headerExtensions.forEach(function(lHeaderExtension) {
+	    for (var i = 0; i < remoteCapabilities.headerExtensions.length;
+	         i++) {
+	      var rHeaderExtension = remoteCapabilities.headerExtensions[i];
+	      if (lHeaderExtension.uri === rHeaderExtension.uri) {
+	        commonCapabilities.headerExtensions.push(rHeaderExtension);
+	        break;
+	      }
+	    }
+	  });
+
+	  // FIXME: fecMechanisms
+	  return commonCapabilities;
+	}
+
+	// is action=setLocalDescription with type allowed in signalingState
+	function isActionAllowedInSignalingState(action, type, signalingState) {
+	  return {
+	    offer: {
+	      setLocalDescription: ['stable', 'have-local-offer'],
+	      setRemoteDescription: ['stable', 'have-remote-offer']
+	    },
+	    answer: {
+	      setLocalDescription: ['have-remote-offer', 'have-local-pranswer'],
+	      setRemoteDescription: ['have-local-offer', 'have-remote-pranswer']
+	    }
+	  }[type][action].indexOf(signalingState) !== -1;
+	}
+
+	function maybeAddCandidate(iceTransport, candidate) {
+	  // Edge's internal representation adds some fields therefore
+	  // not all fieldѕ are taken into account.
+	  var alreadyAdded = iceTransport.getRemoteCandidates()
+	      .find(function(remoteCandidate) {
+	        return candidate.foundation === remoteCandidate.foundation &&
+	            candidate.ip === remoteCandidate.ip &&
+	            candidate.port === remoteCandidate.port &&
+	            candidate.priority === remoteCandidate.priority &&
+	            candidate.protocol === remoteCandidate.protocol &&
+	            candidate.type === remoteCandidate.type;
+	      });
+	  if (!alreadyAdded) {
+	    iceTransport.addRemoteCandidate(candidate);
+	  }
+	  return !alreadyAdded;
+	}
+
+
+	function makeError(name, description) {
+	  var e = new Error(description);
+	  e.name = name;
+	  // legacy error codes from https://heycam.github.io/webidl/#idl-DOMException-error-names
+	  e.code = {
+	    NotSupportedError: 9,
+	    InvalidStateError: 11,
+	    InvalidAccessError: 15,
+	    TypeError: undefined,
+	    OperationError: undefined
+	  }[name];
+	  return e;
+	}
+
+	var rtcpeerconnection = function(window, edgeVersion) {
+	  // https://w3c.github.io/mediacapture-main/#mediastream
+	  // Helper function to add the track to the stream and
+	  // dispatch the event ourselves.
+	  function addTrackToStreamAndFireEvent(track, stream) {
+	    stream.addTrack(track);
+	    stream.dispatchEvent(new window.MediaStreamTrackEvent('addtrack',
+	        {track: track}));
+	  }
+
+	  function removeTrackFromStreamAndFireEvent(track, stream) {
+	    stream.removeTrack(track);
+	    stream.dispatchEvent(new window.MediaStreamTrackEvent('removetrack',
+	        {track: track}));
+	  }
+
+	  function fireAddTrack(pc, track, receiver, streams) {
+	    var trackEvent = new Event('track');
+	    trackEvent.track = track;
+	    trackEvent.receiver = receiver;
+	    trackEvent.transceiver = {receiver: receiver};
+	    trackEvent.streams = streams;
+	    window.setTimeout(function() {
+	      pc._dispatchEvent('track', trackEvent);
+	    });
+	  }
+
+	  var RTCPeerConnection = function(config) {
+	    var pc = this;
+
+	    var _eventTarget = document.createDocumentFragment();
+	    ['addEventListener', 'removeEventListener', 'dispatchEvent']
+	        .forEach(function(method) {
+	          pc[method] = _eventTarget[method].bind(_eventTarget);
+	        });
+
+	    this.canTrickleIceCandidates = null;
+
+	    this.needNegotiation = false;
+
+	    this.localStreams = [];
+	    this.remoteStreams = [];
+
+	    this._localDescription = null;
+	    this._remoteDescription = null;
+
+	    this.signalingState = 'stable';
+	    this.iceConnectionState = 'new';
+	    this.connectionState = 'new';
+	    this.iceGatheringState = 'new';
+
+	    config = JSON.parse(JSON.stringify(config || {}));
+
+	    this.usingBundle = config.bundlePolicy === 'max-bundle';
+	    if (config.rtcpMuxPolicy === 'negotiate') {
+	      throw(makeError('NotSupportedError',
+	          'rtcpMuxPolicy \'negotiate\' is not supported'));
+	    } else if (!config.rtcpMuxPolicy) {
+	      config.rtcpMuxPolicy = 'require';
+	    }
+
+	    switch (config.iceTransportPolicy) {
+	      case 'all':
+	      case 'relay':
+	        break;
+	      default:
+	        config.iceTransportPolicy = 'all';
+	        break;
+	    }
+
+	    switch (config.bundlePolicy) {
+	      case 'balanced':
+	      case 'max-compat':
+	      case 'max-bundle':
+	        break;
+	      default:
+	        config.bundlePolicy = 'balanced';
+	        break;
+	    }
+
+	    config.iceServers = filterIceServers(config.iceServers || [], edgeVersion);
+
+	    this._iceGatherers = [];
+	    if (config.iceCandidatePoolSize) {
+	      for (var i = config.iceCandidatePoolSize; i > 0; i--) {
+	        this._iceGatherers.push(new window.RTCIceGatherer({
+	          iceServers: config.iceServers,
+	          gatherPolicy: config.iceTransportPolicy
+	        }));
+	      }
+	    } else {
+	      config.iceCandidatePoolSize = 0;
+	    }
+
+	    this._config = config;
+
+	    // per-track iceGathers, iceTransports, dtlsTransports, rtpSenders, ...
+	    // everything that is needed to describe a SDP m-line.
+	    this.transceivers = [];
+
+	    this._sdpSessionId = sdp.generateSessionId();
+	    this._sdpSessionVersion = 0;
+
+	    this._dtlsRole = undefined; // role for a=setup to use in answers.
+
+	    this._isClosed = false;
+	  };
+
+	  Object.defineProperty(RTCPeerConnection.prototype, 'localDescription', {
+	    configurable: true,
+	    get: function() {
+	      return this._localDescription;
+	    }
+	  });
+	  Object.defineProperty(RTCPeerConnection.prototype, 'remoteDescription', {
+	    configurable: true,
+	    get: function() {
+	      return this._remoteDescription;
+	    }
+	  });
+
+	  // set up event handlers on prototype
+	  RTCPeerConnection.prototype.onicecandidate = null;
+	  RTCPeerConnection.prototype.onaddstream = null;
+	  RTCPeerConnection.prototype.ontrack = null;
+	  RTCPeerConnection.prototype.onremovestream = null;
+	  RTCPeerConnection.prototype.onsignalingstatechange = null;
+	  RTCPeerConnection.prototype.oniceconnectionstatechange = null;
+	  RTCPeerConnection.prototype.onconnectionstatechange = null;
+	  RTCPeerConnection.prototype.onicegatheringstatechange = null;
+	  RTCPeerConnection.prototype.onnegotiationneeded = null;
+	  RTCPeerConnection.prototype.ondatachannel = null;
+
+	  RTCPeerConnection.prototype._dispatchEvent = function(name, event) {
+	    if (this._isClosed) {
+	      return;
+	    }
+	    this.dispatchEvent(event);
+	    if (typeof this['on' + name] === 'function') {
+	      this['on' + name](event);
+	    }
+	  };
+
+	  RTCPeerConnection.prototype._emitGatheringStateChange = function() {
+	    var event = new Event('icegatheringstatechange');
+	    this._dispatchEvent('icegatheringstatechange', event);
+	  };
+
+	  RTCPeerConnection.prototype.getConfiguration = function() {
+	    return this._config;
+	  };
+
+	  RTCPeerConnection.prototype.getLocalStreams = function() {
+	    return this.localStreams;
+	  };
+
+	  RTCPeerConnection.prototype.getRemoteStreams = function() {
+	    return this.remoteStreams;
+	  };
+
+	  // internal helper to create a transceiver object.
+	  // (which is not yet the same as the WebRTC 1.0 transceiver)
+	  RTCPeerConnection.prototype._createTransceiver = function(kind, doNotAdd) {
+	    var hasBundleTransport = this.transceivers.length > 0;
+	    var transceiver = {
+	      track: null,
+	      iceGatherer: null,
+	      iceTransport: null,
+	      dtlsTransport: null,
+	      localCapabilities: null,
+	      remoteCapabilities: null,
+	      rtpSender: null,
+	      rtpReceiver: null,
+	      kind: kind,
+	      mid: null,
+	      sendEncodingParameters: null,
+	      recvEncodingParameters: null,
+	      stream: null,
+	      associatedRemoteMediaStreams: [],
+	      wantReceive: true
+	    };
+	    if (this.usingBundle && hasBundleTransport) {
+	      transceiver.iceTransport = this.transceivers[0].iceTransport;
+	      transceiver.dtlsTransport = this.transceivers[0].dtlsTransport;
+	    } else {
+	      var transports = this._createIceAndDtlsTransports();
+	      transceiver.iceTransport = transports.iceTransport;
+	      transceiver.dtlsTransport = transports.dtlsTransport;
+	    }
+	    if (!doNotAdd) {
+	      this.transceivers.push(transceiver);
+	    }
+	    return transceiver;
+	  };
+
+	  RTCPeerConnection.prototype.addTrack = function(track, stream) {
+	    if (this._isClosed) {
+	      throw makeError('InvalidStateError',
+	          'Attempted to call addTrack on a closed peerconnection.');
+	    }
+
+	    var alreadyExists = this.transceivers.find(function(s) {
+	      return s.track === track;
+	    });
+
+	    if (alreadyExists) {
+	      throw makeError('InvalidAccessError', 'Track already exists.');
+	    }
+
+	    var transceiver;
+	    for (var i = 0; i < this.transceivers.length; i++) {
+	      if (!this.transceivers[i].track &&
+	          this.transceivers[i].kind === track.kind) {
+	        transceiver = this.transceivers[i];
+	      }
+	    }
+	    if (!transceiver) {
+	      transceiver = this._createTransceiver(track.kind);
+	    }
+
+	    this._maybeFireNegotiationNeeded();
+
+	    if (this.localStreams.indexOf(stream) === -1) {
+	      this.localStreams.push(stream);
+	    }
+
+	    transceiver.track = track;
+	    transceiver.stream = stream;
+	    transceiver.rtpSender = new window.RTCRtpSender(track,
+	        transceiver.dtlsTransport);
+	    return transceiver.rtpSender;
+	  };
+
+	  RTCPeerConnection.prototype.addStream = function(stream) {
+	    var pc = this;
+	    if (edgeVersion >= 15025) {
+	      stream.getTracks().forEach(function(track) {
+	        pc.addTrack(track, stream);
+	      });
+	    } else {
+	      // Clone is necessary for local demos mostly, attaching directly
+	      // to two different senders does not work (build 10547).
+	      // Fixed in 15025 (or earlier)
+	      var clonedStream = stream.clone();
+	      stream.getTracks().forEach(function(track, idx) {
+	        var clonedTrack = clonedStream.getTracks()[idx];
+	        track.addEventListener('enabled', function(event) {
+	          clonedTrack.enabled = event.enabled;
+	        });
+	      });
+	      clonedStream.getTracks().forEach(function(track) {
+	        pc.addTrack(track, clonedStream);
+	      });
+	    }
+	  };
+
+	  RTCPeerConnection.prototype.removeTrack = function(sender) {
+	    if (this._isClosed) {
+	      throw makeError('InvalidStateError',
+	          'Attempted to call removeTrack on a closed peerconnection.');
+	    }
+
+	    if (!(sender instanceof window.RTCRtpSender)) {
+	      throw new TypeError('Argument 1 of RTCPeerConnection.removeTrack ' +
+	          'does not implement interface RTCRtpSender.');
+	    }
+
+	    var transceiver = this.transceivers.find(function(t) {
+	      return t.rtpSender === sender;
+	    });
+
+	    if (!transceiver) {
+	      throw makeError('InvalidAccessError',
+	          'Sender was not created by this connection.');
+	    }
+	    var stream = transceiver.stream;
+
+	    transceiver.rtpSender.stop();
+	    transceiver.rtpSender = null;
+	    transceiver.track = null;
+	    transceiver.stream = null;
+
+	    // remove the stream from the set of local streams
+	    var localStreams = this.transceivers.map(function(t) {
+	      return t.stream;
+	    });
+	    if (localStreams.indexOf(stream) === -1 &&
+	        this.localStreams.indexOf(stream) > -1) {
+	      this.localStreams.splice(this.localStreams.indexOf(stream), 1);
+	    }
+
+	    this._maybeFireNegotiationNeeded();
+	  };
+
+	  RTCPeerConnection.prototype.removeStream = function(stream) {
+	    var pc = this;
+	    stream.getTracks().forEach(function(track) {
+	      var sender = pc.getSenders().find(function(s) {
+	        return s.track === track;
+	      });
+	      if (sender) {
+	        pc.removeTrack(sender);
+	      }
+	    });
+	  };
+
+	  RTCPeerConnection.prototype.getSenders = function() {
+	    return this.transceivers.filter(function(transceiver) {
+	      return !!transceiver.rtpSender;
+	    })
+	    .map(function(transceiver) {
+	      return transceiver.rtpSender;
+	    });
+	  };
+
+	  RTCPeerConnection.prototype.getReceivers = function() {
+	    return this.transceivers.filter(function(transceiver) {
+	      return !!transceiver.rtpReceiver;
+	    })
+	    .map(function(transceiver) {
+	      return transceiver.rtpReceiver;
+	    });
+	  };
+
+
+	  RTCPeerConnection.prototype._createIceGatherer = function(sdpMLineIndex,
+	      usingBundle) {
+	    var pc = this;
+	    if (usingBundle && sdpMLineIndex > 0) {
+	      return this.transceivers[0].iceGatherer;
+	    } else if (this._iceGatherers.length) {
+	      return this._iceGatherers.shift();
+	    }
+	    var iceGatherer = new window.RTCIceGatherer({
+	      iceServers: this._config.iceServers,
+	      gatherPolicy: this._config.iceTransportPolicy
+	    });
+	    Object.defineProperty(iceGatherer, 'state',
+	        {value: 'new', writable: true}
+	    );
+
+	    this.transceivers[sdpMLineIndex].bufferedCandidateEvents = [];
+	    this.transceivers[sdpMLineIndex].bufferCandidates = function(event) {
+	      var end = !event.candidate || Object.keys(event.candidate).length === 0;
+	      // polyfill since RTCIceGatherer.state is not implemented in
+	      // Edge 10547 yet.
+	      iceGatherer.state = end ? 'completed' : 'gathering';
+	      if (pc.transceivers[sdpMLineIndex].bufferedCandidateEvents !== null) {
+	        pc.transceivers[sdpMLineIndex].bufferedCandidateEvents.push(event);
+	      }
+	    };
+	    iceGatherer.addEventListener('localcandidate',
+	      this.transceivers[sdpMLineIndex].bufferCandidates);
+	    return iceGatherer;
+	  };
+
+	  // start gathering from an RTCIceGatherer.
+	  RTCPeerConnection.prototype._gather = function(mid, sdpMLineIndex) {
+	    var pc = this;
+	    var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer;
+	    if (iceGatherer.onlocalcandidate) {
+	      return;
+	    }
+	    var bufferedCandidateEvents =
+	      this.transceivers[sdpMLineIndex].bufferedCandidateEvents;
+	    this.transceivers[sdpMLineIndex].bufferedCandidateEvents = null;
+	    iceGatherer.removeEventListener('localcandidate',
+	      this.transceivers[sdpMLineIndex].bufferCandidates);
+	    iceGatherer.onlocalcandidate = function(evt) {
+	      if (pc.usingBundle && sdpMLineIndex > 0) {
+	        // if we know that we use bundle we can drop candidates with
+	        // ѕdpMLineIndex > 0. If we don't do this then our state gets
+	        // confused since we dispose the extra ice gatherer.
+	        return;
+	      }
+	      var event = new Event('icecandidate');
+	      event.candidate = {sdpMid: mid, sdpMLineIndex: sdpMLineIndex};
+
+	      var cand = evt.candidate;
+	      // Edge emits an empty object for RTCIceCandidateComplete‥
+	      var end = !cand || Object.keys(cand).length === 0;
+	      if (end) {
+	        // polyfill since RTCIceGatherer.state is not implemented in
+	        // Edge 10547 yet.
+	        if (iceGatherer.state === 'new' || iceGatherer.state === 'gathering') {
+	          iceGatherer.state = 'completed';
+	        }
+	      } else {
+	        if (iceGatherer.state === 'new') {
+	          iceGatherer.state = 'gathering';
+	        }
+	        // RTCIceCandidate doesn't have a component, needs to be added
+	        cand.component = 1;
+	        // also the usernameFragment. TODO: update SDP to take both variants.
+	        cand.ufrag = iceGatherer.getLocalParameters().usernameFragment;
+
+	        var serializedCandidate = sdp.writeCandidate(cand);
+	        event.candidate = Object.assign(event.candidate,
+	            sdp.parseCandidate(serializedCandidate));
+
+	        event.candidate.candidate = serializedCandidate;
+	        event.candidate.toJSON = function() {
+	          return {
+	            candidate: event.candidate.candidate,
+	            sdpMid: event.candidate.sdpMid,
+	            sdpMLineIndex: event.candidate.sdpMLineIndex,
+	            usernameFragment: event.candidate.usernameFragment
+	          };
+	        };
+	      }
+
+	      // update local description.
+	      var sections = sdp.getMediaSections(pc._localDescription.sdp);
+	      if (!end) {
+	        sections[event.candidate.sdpMLineIndex] +=
+	            'a=' + event.candidate.candidate + '\r\n';
+	      } else {
+	        sections[event.candidate.sdpMLineIndex] +=
+	            'a=end-of-candidates\r\n';
+	      }
+	      pc._localDescription.sdp =
+	          sdp.getDescription(pc._localDescription.sdp) +
+	          sections.join('');
+	      var complete = pc.transceivers.every(function(transceiver) {
+	        return transceiver.iceGatherer &&
+	            transceiver.iceGatherer.state === 'completed';
+	      });
+
+	      if (pc.iceGatheringState !== 'gathering') {
+	        pc.iceGatheringState = 'gathering';
+	        pc._emitGatheringStateChange();
+	      }
+
+	      // Emit candidate. Also emit null candidate when all gatherers are
+	      // complete.
+	      if (!end) {
+	        pc._dispatchEvent('icecandidate', event);
+	      }
+	      if (complete) {
+	        pc._dispatchEvent('icecandidate', new Event('icecandidate'));
+	        pc.iceGatheringState = 'complete';
+	        pc._emitGatheringStateChange();
+	      }
+	    };
+
+	    // emit already gathered candidates.
+	    window.setTimeout(function() {
+	      bufferedCandidateEvents.forEach(function(e) {
+	        iceGatherer.onlocalcandidate(e);
+	      });
+	    }, 0);
+	  };
+
+	  // Create ICE transport and DTLS transport.
+	  RTCPeerConnection.prototype._createIceAndDtlsTransports = function() {
+	    var pc = this;
+	    var iceTransport = new window.RTCIceTransport(null);
+	    iceTransport.onicestatechange = function() {
+	      pc._updateIceConnectionState();
+	      pc._updateConnectionState();
+	    };
+
+	    var dtlsTransport = new window.RTCDtlsTransport(iceTransport);
+	    dtlsTransport.ondtlsstatechange = function() {
+	      pc._updateConnectionState();
+	    };
+	    dtlsTransport.onerror = function() {
+	      // onerror does not set state to failed by itself.
+	      Object.defineProperty(dtlsTransport, 'state',
+	          {value: 'failed', writable: true});
+	      pc._updateConnectionState();
+	    };
+
+	    return {
+	      iceTransport: iceTransport,
+	      dtlsTransport: dtlsTransport
+	    };
+	  };
+
+	  // Destroy ICE gatherer, ICE transport and DTLS transport.
+	  // Without triggering the callbacks.
+	  RTCPeerConnection.prototype._disposeIceAndDtlsTransports = function(
+	      sdpMLineIndex) {
+	    var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer;
+	    if (iceGatherer) {
+	      delete iceGatherer.onlocalcandidate;
+	      delete this.transceivers[sdpMLineIndex].iceGatherer;
+	    }
+	    var iceTransport = this.transceivers[sdpMLineIndex].iceTransport;
+	    if (iceTransport) {
+	      delete iceTransport.onicestatechange;
+	      delete this.transceivers[sdpMLineIndex].iceTransport;
+	    }
+	    var dtlsTransport = this.transceivers[sdpMLineIndex].dtlsTransport;
+	    if (dtlsTransport) {
+	      delete dtlsTransport.ondtlsstatechange;
+	      delete dtlsTransport.onerror;
+	      delete this.transceivers[sdpMLineIndex].dtlsTransport;
+	    }
+	  };
+
+	  // Start the RTP Sender and Receiver for a transceiver.
+	  RTCPeerConnection.prototype._transceive = function(transceiver,
+	      send, recv) {
+	    var params = getCommonCapabilities(transceiver.localCapabilities,
+	        transceiver.remoteCapabilities);
+	    if (send && transceiver.rtpSender) {
+	      params.encodings = transceiver.sendEncodingParameters;
+	      params.rtcp = {
+	        cname: sdp.localCName,
+	        compound: transceiver.rtcpParameters.compound
+	      };
+	      if (transceiver.recvEncodingParameters.length) {
+	        params.rtcp.ssrc = transceiver.recvEncodingParameters[0].ssrc;
+	      }
+	      transceiver.rtpSender.send(params);
+	    }
+	    if (recv && transceiver.rtpReceiver && params.codecs.length > 0) {
+	      // remove RTX field in Edge 14942
+	      if (transceiver.kind === 'video'
+	          && transceiver.recvEncodingParameters
+	          && edgeVersion < 15019) {
+	        transceiver.recvEncodingParameters.forEach(function(p) {
+	          delete p.rtx;
+	        });
+	      }
+	      if (transceiver.recvEncodingParameters.length) {
+	        params.encodings = transceiver.recvEncodingParameters;
+	      } else {
+	        params.encodings = [{}];
+	      }
+	      params.rtcp = {
+	        compound: transceiver.rtcpParameters.compound
+	      };
+	      if (transceiver.rtcpParameters.cname) {
+	        params.rtcp.cname = transceiver.rtcpParameters.cname;
+	      }
+	      if (transceiver.sendEncodingParameters.length) {
+	        params.rtcp.ssrc = transceiver.sendEncodingParameters[0].ssrc;
+	      }
+	      transceiver.rtpReceiver.receive(params);
+	    }
+	  };
+
+	  RTCPeerConnection.prototype.setLocalDescription = function(description) {
+	    var pc = this;
+
+	    // Note: pranswer is not supported.
+	    if (['offer', 'answer'].indexOf(description.type) === -1) {
+	      return Promise.reject(makeError('TypeError',
+	          'Unsupported type "' + description.type + '"'));
+	    }
+
+	    if (!isActionAllowedInSignalingState('setLocalDescription',
+	        description.type, pc.signalingState) || pc._isClosed) {
+	      return Promise.reject(makeError('InvalidStateError',
+	          'Can not set local ' + description.type +
+	          ' in state ' + pc.signalingState));
+	    }
+
+	    var sections;
+	    var sessionpart;
+	    if (description.type === 'offer') {
+	      // VERY limited support for SDP munging. Limited to:
+	      // * changing the order of codecs
+	      sections = sdp.splitSections(description.sdp);
+	      sessionpart = sections.shift();
+	      sections.forEach(function(mediaSection, sdpMLineIndex) {
+	        var caps = sdp.parseRtpParameters(mediaSection);
+	        pc.transceivers[sdpMLineIndex].localCapabilities = caps;
+	      });
+
+	      pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
+	        pc._gather(transceiver.mid, sdpMLineIndex);
+	      });
+	    } else if (description.type === 'answer') {
+	      sections = sdp.splitSections(pc._remoteDescription.sdp);
+	      sessionpart = sections.shift();
+	      var isIceLite = sdp.matchPrefix(sessionpart,
+	          'a=ice-lite').length > 0;
+	      sections.forEach(function(mediaSection, sdpMLineIndex) {
+	        var transceiver = pc.transceivers[sdpMLineIndex];
+	        var iceGatherer = transceiver.iceGatherer;
+	        var iceTransport = transceiver.iceTransport;
+	        var dtlsTransport = transceiver.dtlsTransport;
+	        var localCapabilities = transceiver.localCapabilities;
+	        var remoteCapabilities = transceiver.remoteCapabilities;
+
+	        // treat bundle-only as not-rejected.
+	        var rejected = sdp.isRejected(mediaSection) &&
+	            sdp.matchPrefix(mediaSection, 'a=bundle-only').length === 0;
+
+	        if (!rejected && !transceiver.rejected) {
+	          var remoteIceParameters = sdp.getIceParameters(
+	              mediaSection, sessionpart);
+	          var remoteDtlsParameters = sdp.getDtlsParameters(
+	              mediaSection, sessionpart);
+	          if (isIceLite) {
+	            remoteDtlsParameters.role = 'server';
+	          }
+
+	          if (!pc.usingBundle || sdpMLineIndex === 0) {
+	            pc._gather(transceiver.mid, sdpMLineIndex);
+	            if (iceTransport.state === 'new') {
+	              iceTransport.start(iceGatherer, remoteIceParameters,
+	                  isIceLite ? 'controlling' : 'controlled');
+	            }
+	            if (dtlsTransport.state === 'new') {
+	              dtlsTransport.start(remoteDtlsParameters);
+	            }
+	          }
+
+	          // Calculate intersection of capabilities.
+	          var params = getCommonCapabilities(localCapabilities,
+	              remoteCapabilities);
+
+	          // Start the RTCRtpSender. The RTCRtpReceiver for this
+	          // transceiver has already been started in setRemoteDescription.
+	          pc._transceive(transceiver,
+	              params.codecs.length > 0,
+	              false);
+	        }
+	      });
+	    }
+
+	    pc._localDescription = {
+	      type: description.type,
+	      sdp: description.sdp
+	    };
+	    if (description.type === 'offer') {
+	      pc._updateSignalingState('have-local-offer');
+	    } else {
+	      pc._updateSignalingState('stable');
+	    }
+
+	    return Promise.resolve();
+	  };
+
+	  RTCPeerConnection.prototype.setRemoteDescription = function(description) {
+	    var pc = this;
+
+	    // Note: pranswer is not supported.
+	    if (['offer', 'answer'].indexOf(description.type) === -1) {
+	      return Promise.reject(makeError('TypeError',
+	          'Unsupported type "' + description.type + '"'));
+	    }
+
+	    if (!isActionAllowedInSignalingState('setRemoteDescription',
+	        description.type, pc.signalingState) || pc._isClosed) {
+	      return Promise.reject(makeError('InvalidStateError',
+	          'Can not set remote ' + description.type +
+	          ' in state ' + pc.signalingState));
+	    }
+
+	    var streams = {};
+	    pc.remoteStreams.forEach(function(stream) {
+	      streams[stream.id] = stream;
+	    });
+	    var receiverList = [];
+	    var sections = sdp.splitSections(description.sdp);
+	    var sessionpart = sections.shift();
+	    var isIceLite = sdp.matchPrefix(sessionpart,
+	        'a=ice-lite').length > 0;
+	    var usingBundle = sdp.matchPrefix(sessionpart,
+	        'a=group:BUNDLE ').length > 0;
+	    pc.usingBundle = usingBundle;
+	    var iceOptions = sdp.matchPrefix(sessionpart,
+	        'a=ice-options:')[0];
+	    if (iceOptions) {
+	      pc.canTrickleIceCandidates = iceOptions.substr(14).split(' ')
+	          .indexOf('trickle') >= 0;
+	    } else {
+	      pc.canTrickleIceCandidates = false;
+	    }
+
+	    sections.forEach(function(mediaSection, sdpMLineIndex) {
+	      var lines = sdp.splitLines(mediaSection);
+	      var kind = sdp.getKind(mediaSection);
+	      // treat bundle-only as not-rejected.
+	      var rejected = sdp.isRejected(mediaSection) &&
+	          sdp.matchPrefix(mediaSection, 'a=bundle-only').length === 0;
+	      var protocol = lines[0].substr(2).split(' ')[2];
+
+	      var direction = sdp.getDirection(mediaSection, sessionpart);
+	      var remoteMsid = sdp.parseMsid(mediaSection);
+
+	      var mid = sdp.getMid(mediaSection) || sdp.generateIdentifier();
+
+	      // Reject datachannels which are not implemented yet.
+	      if (rejected || (kind === 'application' && (protocol === 'DTLS/SCTP' ||
+	          protocol === 'UDP/DTLS/SCTP'))) {
+	        // TODO: this is dangerous in the case where a non-rejected m-line
+	        //     becomes rejected.
+	        pc.transceivers[sdpMLineIndex] = {
+	          mid: mid,
+	          kind: kind,
+	          protocol: protocol,
+	          rejected: true
+	        };
+	        return;
+	      }
+
+	      if (!rejected && pc.transceivers[sdpMLineIndex] &&
+	          pc.transceivers[sdpMLineIndex].rejected) {
+	        // recycle a rejected transceiver.
+	        pc.transceivers[sdpMLineIndex] = pc._createTransceiver(kind, true);
+	      }
+
+	      var transceiver;
+	      var iceGatherer;
+	      var iceTransport;
+	      var dtlsTransport;
+	      var rtpReceiver;
+	      var sendEncodingParameters;
+	      var recvEncodingParameters;
+	      var localCapabilities;
+
+	      var track;
+	      // FIXME: ensure the mediaSection has rtcp-mux set.
+	      var remoteCapabilities = sdp.parseRtpParameters(mediaSection);
+	      var remoteIceParameters;
+	      var remoteDtlsParameters;
+	      if (!rejected) {
+	        remoteIceParameters = sdp.getIceParameters(mediaSection,
+	            sessionpart);
+	        remoteDtlsParameters = sdp.getDtlsParameters(mediaSection,
+	            sessionpart);
+	        remoteDtlsParameters.role = 'client';
+	      }
+	      recvEncodingParameters =
+	          sdp.parseRtpEncodingParameters(mediaSection);
+
+	      var rtcpParameters = sdp.parseRtcpParameters(mediaSection);
+
+	      var isComplete = sdp.matchPrefix(mediaSection,
+	          'a=end-of-candidates', sessionpart).length > 0;
+	      var cands = sdp.matchPrefix(mediaSection, 'a=candidate:')
+	          .map(function(cand) {
+	            return sdp.parseCandidate(cand);
+	          })
+	          .filter(function(cand) {
+	            return cand.component === 1;
+	          });
+
+	      // Check if we can use BUNDLE and dispose transports.
+	      if ((description.type === 'offer' || description.type === 'answer') &&
+	          !rejected && usingBundle && sdpMLineIndex > 0 &&
+	          pc.transceivers[sdpMLineIndex]) {
+	        pc._disposeIceAndDtlsTransports(sdpMLineIndex);
+	        pc.transceivers[sdpMLineIndex].iceGatherer =
+	            pc.transceivers[0].iceGatherer;
+	        pc.transceivers[sdpMLineIndex].iceTransport =
+	            pc.transceivers[0].iceTransport;
+	        pc.transceivers[sdpMLineIndex].dtlsTransport =
+	            pc.transceivers[0].dtlsTransport;
+	        if (pc.transceivers[sdpMLineIndex].rtpSender) {
+	          pc.transceivers[sdpMLineIndex].rtpSender.setTransport(
+	              pc.transceivers[0].dtlsTransport);
+	        }
+	        if (pc.transceivers[sdpMLineIndex].rtpReceiver) {
+	          pc.transceivers[sdpMLineIndex].rtpReceiver.setTransport(
+	              pc.transceivers[0].dtlsTransport);
+	        }
+	      }
+	      if (description.type === 'offer' && !rejected) {
+	        transceiver = pc.transceivers[sdpMLineIndex] ||
+	            pc._createTransceiver(kind);
+	        transceiver.mid = mid;
+
+	        if (!transceiver.iceGatherer) {
+	          transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex,
+	              usingBundle);
+	        }
+
+	        if (cands.length && transceiver.iceTransport.state === 'new') {
+	          if (isComplete && (!usingBundle || sdpMLineIndex === 0)) {
+	            transceiver.iceTransport.setRemoteCandidates(cands);
+	          } else {
+	            cands.forEach(function(candidate) {
+	              maybeAddCandidate(transceiver.iceTransport, candidate);
+	            });
+	          }
+	        }
+
+	        localCapabilities = window.RTCRtpReceiver.getCapabilities(kind);
+
+	        // filter RTX until additional stuff needed for RTX is implemented
+	        // in adapter.js
+	        if (edgeVersion < 15019) {
+	          localCapabilities.codecs = localCapabilities.codecs.filter(
+	              function(codec) {
+	                return codec.name !== 'rtx';
+	              });
+	        }
+
+	        sendEncodingParameters = transceiver.sendEncodingParameters || [{
+	          ssrc: (2 * sdpMLineIndex + 2) * 1001
+	        }];
+
+	        // TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
+	        var isNewTrack = false;
+	        if (direction === 'sendrecv' || direction === 'sendonly') {
+	          isNewTrack = !transceiver.rtpReceiver;
+	          rtpReceiver = transceiver.rtpReceiver ||
+	              new window.RTCRtpReceiver(transceiver.dtlsTransport, kind);
+
+	          if (isNewTrack) {
+	            var stream;
+	            track = rtpReceiver.track;
+	            // FIXME: does not work with Plan B.
+	            if (remoteMsid && remoteMsid.stream === '-') ; else if (remoteMsid) {
+	              if (!streams[remoteMsid.stream]) {
+	                streams[remoteMsid.stream] = new window.MediaStream();
+	                Object.defineProperty(streams[remoteMsid.stream], 'id', {
+	                  get: function() {
+	                    return remoteMsid.stream;
+	                  }
+	                });
+	              }
+	              Object.defineProperty(track, 'id', {
+	                get: function() {
+	                  return remoteMsid.track;
+	                }
+	              });
+	              stream = streams[remoteMsid.stream];
+	            } else {
+	              if (!streams.default) {
+	                streams.default = new window.MediaStream();
+	              }
+	              stream = streams.default;
+	            }
+	            if (stream) {
+	              addTrackToStreamAndFireEvent(track, stream);
+	              transceiver.associatedRemoteMediaStreams.push(stream);
+	            }
+	            receiverList.push([track, rtpReceiver, stream]);
+	          }
+	        } else if (transceiver.rtpReceiver && transceiver.rtpReceiver.track) {
+	          transceiver.associatedRemoteMediaStreams.forEach(function(s) {
+	            var nativeTrack = s.getTracks().find(function(t) {
+	              return t.id === transceiver.rtpReceiver.track.id;
+	            });
+	            if (nativeTrack) {
+	              removeTrackFromStreamAndFireEvent(nativeTrack, s);
+	            }
+	          });
+	          transceiver.associatedRemoteMediaStreams = [];
+	        }
+
+	        transceiver.localCapabilities = localCapabilities;
+	        transceiver.remoteCapabilities = remoteCapabilities;
+	        transceiver.rtpReceiver = rtpReceiver;
+	        transceiver.rtcpParameters = rtcpParameters;
+	        transceiver.sendEncodingParameters = sendEncodingParameters;
+	        transceiver.recvEncodingParameters = recvEncodingParameters;
+
+	        // Start the RTCRtpReceiver now. The RTPSender is started in
+	        // setLocalDescription.
+	        pc._transceive(pc.transceivers[sdpMLineIndex],
+	            false,
+	            isNewTrack);
+	      } else if (description.type === 'answer' && !rejected) {
+	        transceiver = pc.transceivers[sdpMLineIndex];
+	        iceGatherer = transceiver.iceGatherer;
+	        iceTransport = transceiver.iceTransport;
+	        dtlsTransport = transceiver.dtlsTransport;
+	        rtpReceiver = transceiver.rtpReceiver;
+	        sendEncodingParameters = transceiver.sendEncodingParameters;
+	        localCapabilities = transceiver.localCapabilities;
+
+	        pc.transceivers[sdpMLineIndex].recvEncodingParameters =
+	            recvEncodingParameters;
+	        pc.transceivers[sdpMLineIndex].remoteCapabilities =
+	            remoteCapabilities;
+	        pc.transceivers[sdpMLineIndex].rtcpParameters = rtcpParameters;
+
+	        if (cands.length && iceTransport.state === 'new') {
+	          if ((isIceLite || isComplete) &&
+	              (!usingBundle || sdpMLineIndex === 0)) {
+	            iceTransport.setRemoteCandidates(cands);
+	          } else {
+	            cands.forEach(function(candidate) {
+	              maybeAddCandidate(transceiver.iceTransport, candidate);
+	            });
+	          }
+	        }
+
+	        if (!usingBundle || sdpMLineIndex === 0) {
+	          if (iceTransport.state === 'new') {
+	            iceTransport.start(iceGatherer, remoteIceParameters,
+	                'controlling');
+	          }
+	          if (dtlsTransport.state === 'new') {
+	            dtlsTransport.start(remoteDtlsParameters);
+	          }
+	        }
+
+	        // If the offer contained RTX but the answer did not,
+	        // remove RTX from sendEncodingParameters.
+	        var commonCapabilities = getCommonCapabilities(
+	          transceiver.localCapabilities,
+	          transceiver.remoteCapabilities);
+
+	        var hasRtx = commonCapabilities.codecs.filter(function(c) {
+	          return c.name.toLowerCase() === 'rtx';
+	        }).length;
+	        if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
+	          delete transceiver.sendEncodingParameters[0].rtx;
+	        }
+
+	        pc._transceive(transceiver,
+	            direction === 'sendrecv' || direction === 'recvonly',
+	            direction === 'sendrecv' || direction === 'sendonly');
+
+	        // TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
+	        if (rtpReceiver &&
+	            (direction === 'sendrecv' || direction === 'sendonly')) {
+	          track = rtpReceiver.track;
+	          if (remoteMsid) {
+	            if (!streams[remoteMsid.stream]) {
+	              streams[remoteMsid.stream] = new window.MediaStream();
+	            }
+	            addTrackToStreamAndFireEvent(track, streams[remoteMsid.stream]);
+	            receiverList.push([track, rtpReceiver, streams[remoteMsid.stream]]);
+	          } else {
+	            if (!streams.default) {
+	              streams.default = new window.MediaStream();
+	            }
+	            addTrackToStreamAndFireEvent(track, streams.default);
+	            receiverList.push([track, rtpReceiver, streams.default]);
+	          }
+	        } else {
+	          // FIXME: actually the receiver should be created later.
+	          delete transceiver.rtpReceiver;
+	        }
+	      }
+	    });
+
+	    if (pc._dtlsRole === undefined) {
+	      pc._dtlsRole = description.type === 'offer' ? 'active' : 'passive';
+	    }
+
+	    pc._remoteDescription = {
+	      type: description.type,
+	      sdp: description.sdp
+	    };
+	    if (description.type === 'offer') {
+	      pc._updateSignalingState('have-remote-offer');
+	    } else {
+	      pc._updateSignalingState('stable');
+	    }
+	    Object.keys(streams).forEach(function(sid) {
+	      var stream = streams[sid];
+	      if (stream.getTracks().length) {
+	        if (pc.remoteStreams.indexOf(stream) === -1) {
+	          pc.remoteStreams.push(stream);
+	          var event = new Event('addstream');
+	          event.stream = stream;
+	          window.setTimeout(function() {
+	            pc._dispatchEvent('addstream', event);
+	          });
+	        }
+
+	        receiverList.forEach(function(item) {
+	          var track = item[0];
+	          var receiver = item[1];
+	          if (stream.id !== item[2].id) {
+	            return;
+	          }
+	          fireAddTrack(pc, track, receiver, [stream]);
+	        });
+	      }
+	    });
+	    receiverList.forEach(function(item) {
+	      if (item[2]) {
+	        return;
+	      }
+	      fireAddTrack(pc, item[0], item[1], []);
+	    });
+
+	    // check whether addIceCandidate({}) was called within four seconds after
+	    // setRemoteDescription.
+	    window.setTimeout(function() {
+	      if (!(pc && pc.transceivers)) {
+	        return;
+	      }
+	      pc.transceivers.forEach(function(transceiver) {
+	        if (transceiver.iceTransport &&
+	            transceiver.iceTransport.state === 'new' &&
+	            transceiver.iceTransport.getRemoteCandidates().length > 0) {
+	          console.warn('Timeout for addRemoteCandidate. Consider sending ' +
+	              'an end-of-candidates notification');
+	          transceiver.iceTransport.addRemoteCandidate({});
+	        }
+	      });
+	    }, 4000);
+
+	    return Promise.resolve();
+	  };
+
+	  RTCPeerConnection.prototype.close = function() {
+	    this.transceivers.forEach(function(transceiver) {
+	      /* not yet
+	      if (transceiver.iceGatherer) {
+	        transceiver.iceGatherer.close();
+	      }
+	      */
+	      if (transceiver.iceTransport) {
+	        transceiver.iceTransport.stop();
+	      }
+	      if (transceiver.dtlsTransport) {
+	        transceiver.dtlsTransport.stop();
+	      }
+	      if (transceiver.rtpSender) {
+	        transceiver.rtpSender.stop();
+	      }
+	      if (transceiver.rtpReceiver) {
+	        transceiver.rtpReceiver.stop();
+	      }
+	    });
+	    // FIXME: clean up tracks, local streams, remote streams, etc
+	    this._isClosed = true;
+	    this._updateSignalingState('closed');
+	  };
+
+	  // Update the signaling state.
+	  RTCPeerConnection.prototype._updateSignalingState = function(newState) {
+	    this.signalingState = newState;
+	    var event = new Event('signalingstatechange');
+	    this._dispatchEvent('signalingstatechange', event);
+	  };
+
+	  // Determine whether to fire the negotiationneeded event.
+	  RTCPeerConnection.prototype._maybeFireNegotiationNeeded = function() {
+	    var pc = this;
+	    if (this.signalingState !== 'stable' || this.needNegotiation === true) {
+	      return;
+	    }
+	    this.needNegotiation = true;
+	    window.setTimeout(function() {
+	      if (pc.needNegotiation) {
+	        pc.needNegotiation = false;
+	        var event = new Event('negotiationneeded');
+	        pc._dispatchEvent('negotiationneeded', event);
+	      }
+	    }, 0);
+	  };
+
+	  // Update the ice connection state.
+	  RTCPeerConnection.prototype._updateIceConnectionState = function() {
+	    var newState;
+	    var states = {
+	      'new': 0,
+	      closed: 0,
+	      checking: 0,
+	      connected: 0,
+	      completed: 0,
+	      disconnected: 0,
+	      failed: 0
+	    };
+	    this.transceivers.forEach(function(transceiver) {
+	      if (transceiver.iceTransport && !transceiver.rejected) {
+	        states[transceiver.iceTransport.state]++;
+	      }
+	    });
+
+	    newState = 'new';
+	    if (states.failed > 0) {
+	      newState = 'failed';
+	    } else if (states.checking > 0) {
+	      newState = 'checking';
+	    } else if (states.disconnected > 0) {
+	      newState = 'disconnected';
+	    } else if (states.new > 0) {
+	      newState = 'new';
+	    } else if (states.connected > 0) {
+	      newState = 'connected';
+	    } else if (states.completed > 0) {
+	      newState = 'completed';
+	    }
+
+	    if (newState !== this.iceConnectionState) {
+	      this.iceConnectionState = newState;
+	      var event = new Event('iceconnectionstatechange');
+	      this._dispatchEvent('iceconnectionstatechange', event);
+	    }
+	  };
+
+	  // Update the connection state.
+	  RTCPeerConnection.prototype._updateConnectionState = function() {
+	    var newState;
+	    var states = {
+	      'new': 0,
+	      closed: 0,
+	      connecting: 0,
+	      connected: 0,
+	      completed: 0,
+	      disconnected: 0,
+	      failed: 0
+	    };
+	    this.transceivers.forEach(function(transceiver) {
+	      if (transceiver.iceTransport && transceiver.dtlsTransport &&
+	          !transceiver.rejected) {
+	        states[transceiver.iceTransport.state]++;
+	        states[transceiver.dtlsTransport.state]++;
+	      }
+	    });
+	    // ICETransport.completed and connected are the same for this purpose.
+	    states.connected += states.completed;
+
+	    newState = 'new';
+	    if (states.failed > 0) {
+	      newState = 'failed';
+	    } else if (states.connecting > 0) {
+	      newState = 'connecting';
+	    } else if (states.disconnected > 0) {
+	      newState = 'disconnected';
+	    } else if (states.new > 0) {
+	      newState = 'new';
+	    } else if (states.connected > 0) {
+	      newState = 'connected';
+	    }
+
+	    if (newState !== this.connectionState) {
+	      this.connectionState = newState;
+	      var event = new Event('connectionstatechange');
+	      this._dispatchEvent('connectionstatechange', event);
+	    }
+	  };
+
+	  RTCPeerConnection.prototype.createOffer = function() {
+	    var pc = this;
+
+	    if (pc._isClosed) {
+	      return Promise.reject(makeError('InvalidStateError',
+	          'Can not call createOffer after close'));
+	    }
+
+	    var numAudioTracks = pc.transceivers.filter(function(t) {
+	      return t.kind === 'audio';
+	    }).length;
+	    var numVideoTracks = pc.transceivers.filter(function(t) {
+	      return t.kind === 'video';
+	    }).length;
+
+	    // Determine number of audio and video tracks we need to send/recv.
+	    var offerOptions = arguments[0];
+	    if (offerOptions) {
+	      // Reject Chrome legacy constraints.
+	      if (offerOptions.mandatory || offerOptions.optional) {
+	        throw new TypeError(
+	            'Legacy mandatory/optional constraints not supported.');
+	      }
+	      if (offerOptions.offerToReceiveAudio !== undefined) {
+	        if (offerOptions.offerToReceiveAudio === true) {
+	          numAudioTracks = 1;
+	        } else if (offerOptions.offerToReceiveAudio === false) {
+	          numAudioTracks = 0;
+	        } else {
+	          numAudioTracks = offerOptions.offerToReceiveAudio;
+	        }
+	      }
+	      if (offerOptions.offerToReceiveVideo !== undefined) {
+	        if (offerOptions.offerToReceiveVideo === true) {
+	          numVideoTracks = 1;
+	        } else if (offerOptions.offerToReceiveVideo === false) {
+	          numVideoTracks = 0;
+	        } else {
+	          numVideoTracks = offerOptions.offerToReceiveVideo;
+	        }
+	      }
+	    }
+
+	    pc.transceivers.forEach(function(transceiver) {
+	      if (transceiver.kind === 'audio') {
+	        numAudioTracks--;
+	        if (numAudioTracks < 0) {
+	          transceiver.wantReceive = false;
+	        }
+	      } else if (transceiver.kind === 'video') {
+	        numVideoTracks--;
+	        if (numVideoTracks < 0) {
+	          transceiver.wantReceive = false;
+	        }
+	      }
+	    });
+
+	    // Create M-lines for recvonly streams.
+	    while (numAudioTracks > 0 || numVideoTracks > 0) {
+	      if (numAudioTracks > 0) {
+	        pc._createTransceiver('audio');
+	        numAudioTracks--;
+	      }
+	      if (numVideoTracks > 0) {
+	        pc._createTransceiver('video');
+	        numVideoTracks--;
+	      }
+	    }
+
+	    var sdp$1 = sdp.writeSessionBoilerplate(pc._sdpSessionId,
+	        pc._sdpSessionVersion++);
+	    pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
+	      // For each track, create an ice gatherer, ice transport,
+	      // dtls transport, potentially rtpsender and rtpreceiver.
+	      var track = transceiver.track;
+	      var kind = transceiver.kind;
+	      var mid = transceiver.mid || sdp.generateIdentifier();
+	      transceiver.mid = mid;
+
+	      if (!transceiver.iceGatherer) {
+	        transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex,
+	            pc.usingBundle);
+	      }
+
+	      var localCapabilities = window.RTCRtpSender.getCapabilities(kind);
+	      // filter RTX until additional stuff needed for RTX is implemented
+	      // in adapter.js
+	      if (edgeVersion < 15019) {
+	        localCapabilities.codecs = localCapabilities.codecs.filter(
+	            function(codec) {
+	              return codec.name !== 'rtx';
+	            });
+	      }
+	      localCapabilities.codecs.forEach(function(codec) {
+	        // work around https://bugs.chromium.org/p/webrtc/issues/detail?id=6552
+	        // by adding level-asymmetry-allowed=1
+	        if (codec.name === 'H264' &&
+	            codec.parameters['level-asymmetry-allowed'] === undefined) {
+	          codec.parameters['level-asymmetry-allowed'] = '1';
+	        }
+
+	        // for subsequent offers, we might have to re-use the payload
+	        // type of the last offer.
+	        if (transceiver.remoteCapabilities &&
+	            transceiver.remoteCapabilities.codecs) {
+	          transceiver.remoteCapabilities.codecs.forEach(function(remoteCodec) {
+	            if (codec.name.toLowerCase() === remoteCodec.name.toLowerCase() &&
+	                codec.clockRate === remoteCodec.clockRate) {
+	              codec.preferredPayloadType = remoteCodec.payloadType;
+	            }
+	          });
+	        }
+	      });
+	      localCapabilities.headerExtensions.forEach(function(hdrExt) {
+	        var remoteExtensions = transceiver.remoteCapabilities &&
+	            transceiver.remoteCapabilities.headerExtensions || [];
+	        remoteExtensions.forEach(function(rHdrExt) {
+	          if (hdrExt.uri === rHdrExt.uri) {
+	            hdrExt.id = rHdrExt.id;
+	          }
+	        });
+	      });
+
+	      // generate an ssrc now, to be used later in rtpSender.send
+	      var sendEncodingParameters = transceiver.sendEncodingParameters || [{
+	        ssrc: (2 * sdpMLineIndex + 1) * 1001
+	      }];
+	      if (track) {
+	        // add RTX
+	        if (edgeVersion >= 15019 && kind === 'video' &&
+	            !sendEncodingParameters[0].rtx) {
+	          sendEncodingParameters[0].rtx = {
+	            ssrc: sendEncodingParameters[0].ssrc + 1
+	          };
+	        }
+	      }
+
+	      if (transceiver.wantReceive) {
+	        transceiver.rtpReceiver = new window.RTCRtpReceiver(
+	            transceiver.dtlsTransport, kind);
+	      }
+
+	      transceiver.localCapabilities = localCapabilities;
+	      transceiver.sendEncodingParameters = sendEncodingParameters;
+	    });
+
+	    // always offer BUNDLE and dispose on return if not supported.
+	    if (pc._config.bundlePolicy !== 'max-compat') {
+	      sdp$1 += 'a=group:BUNDLE ' + pc.transceivers.map(function(t) {
+	        return t.mid;
+	      }).join(' ') + '\r\n';
+	    }
+	    sdp$1 += 'a=ice-options:trickle\r\n';
+
+	    pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
+	      sdp$1 += writeMediaSection(transceiver, transceiver.localCapabilities,
+	          'offer', transceiver.stream, pc._dtlsRole);
+	      sdp$1 += 'a=rtcp-rsize\r\n';
+
+	      if (transceiver.iceGatherer && pc.iceGatheringState !== 'new' &&
+	          (sdpMLineIndex === 0 || !pc.usingBundle)) {
+	        transceiver.iceGatherer.getLocalCandidates().forEach(function(cand) {
+	          cand.component = 1;
+	          sdp$1 += 'a=' + sdp.writeCandidate(cand) + '\r\n';
+	        });
+
+	        if (transceiver.iceGatherer.state === 'completed') {
+	          sdp$1 += 'a=end-of-candidates\r\n';
+	        }
+	      }
+	    });
+
+	    var desc = new window.RTCSessionDescription({
+	      type: 'offer',
+	      sdp: sdp$1
+	    });
+	    return Promise.resolve(desc);
+	  };
+
+	  RTCPeerConnection.prototype.createAnswer = function() {
+	    var pc = this;
+
+	    if (pc._isClosed) {
+	      return Promise.reject(makeError('InvalidStateError',
+	          'Can not call createAnswer after close'));
+	    }
+
+	    if (!(pc.signalingState === 'have-remote-offer' ||
+	        pc.signalingState === 'have-local-pranswer')) {
+	      return Promise.reject(makeError('InvalidStateError',
+	          'Can not call createAnswer in signalingState ' + pc.signalingState));
+	    }
+
+	    var sdp$1 = sdp.writeSessionBoilerplate(pc._sdpSessionId,
+	        pc._sdpSessionVersion++);
+	    if (pc.usingBundle) {
+	      sdp$1 += 'a=group:BUNDLE ' + pc.transceivers.map(function(t) {
+	        return t.mid;
+	      }).join(' ') + '\r\n';
+	    }
+	    sdp$1 += 'a=ice-options:trickle\r\n';
+
+	    var mediaSectionsInOffer = sdp.getMediaSections(
+	        pc._remoteDescription.sdp).length;
+	    pc.transceivers.forEach(function(transceiver, sdpMLineIndex) {
+	      if (sdpMLineIndex + 1 > mediaSectionsInOffer) {
+	        return;
+	      }
+	      if (transceiver.rejected) {
+	        if (transceiver.kind === 'application') {
+	          if (transceiver.protocol === 'DTLS/SCTP') { // legacy fmt
+	            sdp$1 += 'm=application 0 DTLS/SCTP 5000\r\n';
+	          } else {
+	            sdp$1 += 'm=application 0 ' + transceiver.protocol +
+	                ' webrtc-datachannel\r\n';
+	          }
+	        } else if (transceiver.kind === 'audio') {
+	          sdp$1 += 'm=audio 0 UDP/TLS/RTP/SAVPF 0\r\n' +
+	              'a=rtpmap:0 PCMU/8000\r\n';
+	        } else if (transceiver.kind === 'video') {
+	          sdp$1 += 'm=video 0 UDP/TLS/RTP/SAVPF 120\r\n' +
+	              'a=rtpmap:120 VP8/90000\r\n';
+	        }
+	        sdp$1 += 'c=IN IP4 0.0.0.0\r\n' +
+	            'a=inactive\r\n' +
+	            'a=mid:' + transceiver.mid + '\r\n';
+	        return;
+	      }
+
+	      // FIXME: look at direction.
+	      if (transceiver.stream) {
+	        var localTrack;
+	        if (transceiver.kind === 'audio') {
+	          localTrack = transceiver.stream.getAudioTracks()[0];
+	        } else if (transceiver.kind === 'video') {
+	          localTrack = transceiver.stream.getVideoTracks()[0];
+	        }
+	        if (localTrack) {
+	          // add RTX
+	          if (edgeVersion >= 15019 && transceiver.kind === 'video' &&
+	              !transceiver.sendEncodingParameters[0].rtx) {
+	            transceiver.sendEncodingParameters[0].rtx = {
+	              ssrc: transceiver.sendEncodingParameters[0].ssrc + 1
+	            };
+	          }
+	        }
+	      }
+
+	      // Calculate intersection of capabilities.
+	      var commonCapabilities = getCommonCapabilities(
+	          transceiver.localCapabilities,
+	          transceiver.remoteCapabilities);
+
+	      var hasRtx = commonCapabilities.codecs.filter(function(c) {
+	        return c.name.toLowerCase() === 'rtx';
+	      }).length;
+	      if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
+	        delete transceiver.sendEncodingParameters[0].rtx;
+	      }
+
+	      sdp$1 += writeMediaSection(transceiver, commonCapabilities,
+	          'answer', transceiver.stream, pc._dtlsRole);
+	      if (transceiver.rtcpParameters &&
+	          transceiver.rtcpParameters.reducedSize) {
+	        sdp$1 += 'a=rtcp-rsize\r\n';
+	      }
+	    });
+
+	    var desc = new window.RTCSessionDescription({
+	      type: 'answer',
+	      sdp: sdp$1
+	    });
+	    return Promise.resolve(desc);
+	  };
+
+	  RTCPeerConnection.prototype.addIceCandidate = function(candidate) {
+	    var pc = this;
+	    var sections;
+	    if (candidate && !(candidate.sdpMLineIndex !== undefined ||
+	        candidate.sdpMid)) {
+	      return Promise.reject(new TypeError('sdpMLineIndex or sdpMid required'));
+	    }
+
+	    // TODO: needs to go into ops queue.
+	    return new Promise(function(resolve, reject) {
+	      if (!pc._remoteDescription) {
+	        return reject(makeError('InvalidStateError',
+	            'Can not add ICE candidate without a remote description'));
+	      } else if (!candidate || candidate.candidate === '') {
+	        for (var j = 0; j < pc.transceivers.length; j++) {
+	          if (pc.transceivers[j].rejected) {
+	            continue;
+	          }
+	          pc.transceivers[j].iceTransport.addRemoteCandidate({});
+	          sections = sdp.getMediaSections(pc._remoteDescription.sdp);
+	          sections[j] += 'a=end-of-candidates\r\n';
+	          pc._remoteDescription.sdp =
+	              sdp.getDescription(pc._remoteDescription.sdp) +
+	              sections.join('');
+	          if (pc.usingBundle) {
+	            break;
+	          }
+	        }
+	      } else {
+	        var sdpMLineIndex = candidate.sdpMLineIndex;
+	        if (candidate.sdpMid) {
+	          for (var i = 0; i < pc.transceivers.length; i++) {
+	            if (pc.transceivers[i].mid === candidate.sdpMid) {
+	              sdpMLineIndex = i;
+	              break;
+	            }
+	          }
+	        }
+	        var transceiver = pc.transceivers[sdpMLineIndex];
+	        if (transceiver) {
+	          if (transceiver.rejected) {
+	            return resolve();
+	          }
+	          var cand = Object.keys(candidate.candidate).length > 0 ?
+	              sdp.parseCandidate(candidate.candidate) : {};
+	          // Ignore Chrome's invalid candidates since Edge does not like them.
+	          if (cand.protocol === 'tcp' && (cand.port === 0 || cand.port === 9)) {
+	            return resolve();
+	          }
+	          // Ignore RTCP candidates, we assume RTCP-MUX.
+	          if (cand.component && cand.component !== 1) {
+	            return resolve();
+	          }
+	          // when using bundle, avoid adding candidates to the wrong
+	          // ice transport. And avoid adding candidates added in the SDP.
+	          if (sdpMLineIndex === 0 || (sdpMLineIndex > 0 &&
+	              transceiver.iceTransport !== pc.transceivers[0].iceTransport)) {
+	            if (!maybeAddCandidate(transceiver.iceTransport, cand)) {
+	              return reject(makeError('OperationError',
+	                  'Can not add ICE candidate'));
+	            }
+	          }
+
+	          // update the remoteDescription.
+	          var candidateString = candidate.candidate.trim();
+	          if (candidateString.indexOf('a=') === 0) {
+	            candidateString = candidateString.substr(2);
+	          }
+	          sections = sdp.getMediaSections(pc._remoteDescription.sdp);
+	          sections[sdpMLineIndex] += 'a=' +
+	              (cand.type ? candidateString : 'end-of-candidates')
+	              + '\r\n';
+	          pc._remoteDescription.sdp =
+	              sdp.getDescription(pc._remoteDescription.sdp) +
+	              sections.join('');
+	        } else {
+	          return reject(makeError('OperationError',
+	              'Can not add ICE candidate'));
+	        }
+	      }
+	      resolve();
+	    });
+	  };
+
+	  RTCPeerConnection.prototype.getStats = function(selector) {
+	    if (selector && selector instanceof window.MediaStreamTrack) {
+	      var senderOrReceiver = null;
+	      this.transceivers.forEach(function(transceiver) {
+	        if (transceiver.rtpSender &&
+	            transceiver.rtpSender.track === selector) {
+	          senderOrReceiver = transceiver.rtpSender;
+	        } else if (transceiver.rtpReceiver &&
+	            transceiver.rtpReceiver.track === selector) {
+	          senderOrReceiver = transceiver.rtpReceiver;
+	        }
+	      });
+	      if (!senderOrReceiver) {
+	        throw makeError('InvalidAccessError', 'Invalid selector.');
+	      }
+	      return senderOrReceiver.getStats();
+	    }
+
+	    var promises = [];
+	    this.transceivers.forEach(function(transceiver) {
+	      ['rtpSender', 'rtpReceiver', 'iceGatherer', 'iceTransport',
+	          'dtlsTransport'].forEach(function(method) {
+	            if (transceiver[method]) {
+	              promises.push(transceiver[method].getStats());
+	            }
+	          });
+	    });
+	    return Promise.all(promises).then(function(allStats) {
+	      var results = new Map();
+	      allStats.forEach(function(stats) {
+	        stats.forEach(function(stat) {
+	          results.set(stat.id, stat);
+	        });
+	      });
+	      return results;
+	    });
+	  };
+
+	  // fix low-level stat names and return Map instead of object.
+	  var ortcObjects = ['RTCRtpSender', 'RTCRtpReceiver', 'RTCIceGatherer',
+	    'RTCIceTransport', 'RTCDtlsTransport'];
+	  ortcObjects.forEach(function(ortcObjectName) {
+	    var obj = window[ortcObjectName];
+	    if (obj && obj.prototype && obj.prototype.getStats) {
+	      var nativeGetstats = obj.prototype.getStats;
+	      obj.prototype.getStats = function() {
+	        return nativeGetstats.apply(this)
+	        .then(function(nativeStats) {
+	          var mapStats = new Map();
+	          Object.keys(nativeStats).forEach(function(id) {
+	            nativeStats[id].type = fixStatsType(nativeStats[id]);
+	            mapStats.set(id, nativeStats[id]);
+	          });
+	          return mapStats;
+	        });
+	      };
+	    }
+	  });
+
+	  // legacy callback shims. Should be moved to adapter.js some days.
+	  var methods = ['createOffer', 'createAnswer'];
+	  methods.forEach(function(method) {
+	    var nativeMethod = RTCPeerConnection.prototype[method];
+	    RTCPeerConnection.prototype[method] = function() {
+	      var args = arguments;
+	      if (typeof args[0] === 'function' ||
+	          typeof args[1] === 'function') { // legacy
+	        return nativeMethod.apply(this, [arguments[2]])
+	        .then(function(description) {
+	          if (typeof args[0] === 'function') {
+	            args[0].apply(null, [description]);
+	          }
+	        }, function(error) {
+	          if (typeof args[1] === 'function') {
+	            args[1].apply(null, [error]);
+	          }
+	        });
+	      }
+	      return nativeMethod.apply(this, arguments);
+	    };
+	  });
+
+	  methods = ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate'];
+	  methods.forEach(function(method) {
+	    var nativeMethod = RTCPeerConnection.prototype[method];
+	    RTCPeerConnection.prototype[method] = function() {
+	      var args = arguments;
+	      if (typeof args[1] === 'function' ||
+	          typeof args[2] === 'function') { // legacy
+	        return nativeMethod.apply(this, arguments)
+	        .then(function() {
+	          if (typeof args[1] === 'function') {
+	            args[1].apply(null);
+	          }
+	        }, function(error) {
+	          if (typeof args[2] === 'function') {
+	            args[2].apply(null, [error]);
+	          }
+	        });
+	      }
+	      return nativeMethod.apply(this, arguments);
+	    };
+	  });
+
+	  // getStats is special. It doesn't have a spec legacy method yet we support
+	  // getStats(something, cb) without error callbacks.
+	  ['getStats'].forEach(function(method) {
+	    var nativeMethod = RTCPeerConnection.prototype[method];
+	    RTCPeerConnection.prototype[method] = function() {
+	      var args = arguments;
+	      if (typeof args[1] === 'function') {
+	        return nativeMethod.apply(this, arguments)
+	        .then(function() {
+	          if (typeof args[1] === 'function') {
+	            args[1].apply(null);
+	          }
+	        });
+	      }
+	      return nativeMethod.apply(this, arguments);
+	    };
+	  });
+
+	  return RTCPeerConnection;
+	};
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimGetUserMedia$2(window) {
+	  const navigator = window && window.navigator;
+
+	  const shimError_ = function(e) {
+	    return {
+	      name: {PermissionDeniedError: 'NotAllowedError'}[e.name] || e.name,
+	      message: e.message,
+	      constraint: e.constraint,
+	      toString() {
+	        return this.name;
+	      }
+	    };
+	  };
+
+	  // getUserMedia error shim.
+	  const origGetUserMedia = navigator.mediaDevices.getUserMedia.
+	      bind(navigator.mediaDevices);
+	  navigator.mediaDevices.getUserMedia = function(c) {
+	    return origGetUserMedia(c).catch(e => Promise.reject(shimError_(e)));
+	  };
+	}
+
+	/*
+	 *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimGetDisplayMedia$1(window) {
+	  if (!('getDisplayMedia' in window.navigator)) {
+	    return;
+	  }
+	  if (!(window.navigator.mediaDevices)) {
+	    return;
+	  }
+	  if (window.navigator.mediaDevices &&
+	    'getDisplayMedia' in window.navigator.mediaDevices) {
+	    return;
+	  }
+	  window.navigator.mediaDevices.getDisplayMedia =
+	    window.navigator.getDisplayMedia.bind(window.navigator);
+	}
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimPeerConnection$1(window, browserDetails) {
+	  if (window.RTCIceGatherer) {
+	    if (!window.RTCIceCandidate) {
+	      window.RTCIceCandidate = function RTCIceCandidate(args) {
+	        return args;
+	      };
+	    }
+	    if (!window.RTCSessionDescription) {
+	      window.RTCSessionDescription = function RTCSessionDescription(args) {
+	        return args;
+	      };
+	    }
+	    // this adds an additional event listener to MediaStrackTrack that signals
+	    // when a tracks enabled property was changed. Workaround for a bug in
+	    // addStream, see below. No longer required in 15025+
+	    if (browserDetails.version < 15025) {
+	      const origMSTEnabled = Object.getOwnPropertyDescriptor(
+	          window.MediaStreamTrack.prototype, 'enabled');
+	      Object.defineProperty(window.MediaStreamTrack.prototype, 'enabled', {
+	        set(value) {
+	          origMSTEnabled.set.call(this, value);
+	          const ev = new Event('enabled');
+	          ev.enabled = value;
+	          this.dispatchEvent(ev);
+	        }
+	      });
+	    }
+	  }
+
+	  // ORTC defines the DTMF sender a bit different.
+	  // https://github.com/w3c/ortc/issues/714
+	  if (window.RTCRtpSender && !('dtmf' in window.RTCRtpSender.prototype)) {
+	    Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
+	      get() {
+	        if (this._dtmf === undefined) {
+	          if (this.track.kind === 'audio') {
+	            this._dtmf = new window.RTCDtmfSender(this);
+	          } else if (this.track.kind === 'video') {
+	            this._dtmf = null;
+	          }
+	        }
+	        return this._dtmf;
+	      }
+	    });
+	  }
+	  // Edge currently only implements the RTCDtmfSender, not the
+	  // RTCDTMFSender alias. See http://draft.ortc.org/#rtcdtmfsender2*
+	  if (window.RTCDtmfSender && !window.RTCDTMFSender) {
+	    window.RTCDTMFSender = window.RTCDtmfSender;
+	  }
+
+	  const RTCPeerConnectionShim = rtcpeerconnection(window,
+	      browserDetails.version);
+	  window.RTCPeerConnection = function RTCPeerConnection(config) {
+	    if (config && config.iceServers) {
+	      config.iceServers = filterIceServers$1(config.iceServers,
+	        browserDetails.version);
+	      log$1('ICE servers after filtering:', config.iceServers);
+	    }
+	    return new RTCPeerConnectionShim(config);
+	  };
+	  window.RTCPeerConnection.prototype = RTCPeerConnectionShim.prototype;
+	}
+
+	function shimReplaceTrack(window) {
+	  // ORTC has replaceTrack -- https://github.com/w3c/ortc/issues/614
+	  if (window.RTCRtpSender &&
+	      !('replaceTrack' in window.RTCRtpSender.prototype)) {
+	    window.RTCRtpSender.prototype.replaceTrack =
+	        window.RTCRtpSender.prototype.setTrack;
+	  }
+	}
+
+	var edgeShim = /*#__PURE__*/Object.freeze({
+		__proto__: null,
+		shimPeerConnection: shimPeerConnection$1,
+		shimReplaceTrack: shimReplaceTrack,
+		shimGetUserMedia: shimGetUserMedia$2,
+		shimGetDisplayMedia: shimGetDisplayMedia$1
+	});
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimGetUserMedia$1(window, browserDetails) {
+	  const navigator = window && window.navigator;
+	  const MediaStreamTrack = window && window.MediaStreamTrack;
+
+	  navigator.getUserMedia = function(constraints, onSuccess, onError) {
+	    // Replace Firefox 44+'s deprecation warning with unprefixed version.
+	    deprecated('navigator.getUserMedia',
+	        'navigator.mediaDevices.getUserMedia');
+	    navigator.mediaDevices.getUserMedia(constraints).then(onSuccess, onError);
+	  };
+
+	  if (!(browserDetails.version > 55 &&
+	      'autoGainControl' in navigator.mediaDevices.getSupportedConstraints())) {
+	    const remap = function(obj, a, b) {
+	      if (a in obj && !(b in obj)) {
+	        obj[b] = obj[a];
+	        delete obj[a];
+	      }
+	    };
+
+	    const nativeGetUserMedia = navigator.mediaDevices.getUserMedia.
+	        bind(navigator.mediaDevices);
+	    navigator.mediaDevices.getUserMedia = function(c) {
+	      if (typeof c === 'object' && typeof c.audio === 'object') {
+	        c = JSON.parse(JSON.stringify(c));
+	        remap(c.audio, 'autoGainControl', 'mozAutoGainControl');
+	        remap(c.audio, 'noiseSuppression', 'mozNoiseSuppression');
+	      }
+	      return nativeGetUserMedia(c);
+	    };
+
+	    if (MediaStreamTrack && MediaStreamTrack.prototype.getSettings) {
+	      const nativeGetSettings = MediaStreamTrack.prototype.getSettings;
+	      MediaStreamTrack.prototype.getSettings = function() {
+	        const obj = nativeGetSettings.apply(this, arguments);
+	        remap(obj, 'mozAutoGainControl', 'autoGainControl');
+	        remap(obj, 'mozNoiseSuppression', 'noiseSuppression');
+	        return obj;
+	      };
+	    }
+
+	    if (MediaStreamTrack && MediaStreamTrack.prototype.applyConstraints) {
+	      const nativeApplyConstraints =
+	        MediaStreamTrack.prototype.applyConstraints;
+	      MediaStreamTrack.prototype.applyConstraints = function(c) {
+	        if (this.kind === 'audio' && typeof c === 'object') {
+	          c = JSON.parse(JSON.stringify(c));
+	          remap(c, 'autoGainControl', 'mozAutoGainControl');
+	          remap(c, 'noiseSuppression', 'mozNoiseSuppression');
+	        }
+	        return nativeApplyConstraints.apply(this, [c]);
+	      };
+	    }
+	  }
+	}
+
+	/*
+	 *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimGetDisplayMedia(window, preferredMediaSource) {
+	  if (window.navigator.mediaDevices &&
+	    'getDisplayMedia' in window.navigator.mediaDevices) {
+	    return;
+	  }
+	  if (!(window.navigator.mediaDevices)) {
+	    return;
+	  }
+	  window.navigator.mediaDevices.getDisplayMedia =
+	    function getDisplayMedia(constraints) {
+	      if (!(constraints && constraints.video)) {
+	        const err = new DOMException('getDisplayMedia without video ' +
+	            'constraints is undefined');
+	        err.name = 'NotFoundError';
+	        // from https://heycam.github.io/webidl/#idl-DOMException-error-names
+	        err.code = 8;
+	        return Promise.reject(err);
+	      }
+	      if (constraints.video === true) {
+	        constraints.video = {mediaSource: preferredMediaSource};
+	      } else {
+	        constraints.video.mediaSource = preferredMediaSource;
+	      }
+	      return window.navigator.mediaDevices.getUserMedia(constraints);
+	    };
+	}
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimOnTrack(window) {
+	  if (typeof window === 'object' && window.RTCTrackEvent &&
+	      ('receiver' in window.RTCTrackEvent.prototype) &&
+	      !('transceiver' in window.RTCTrackEvent.prototype)) {
+	    Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
+	      get() {
+	        return {receiver: this.receiver};
+	      }
+	    });
+	  }
+	}
+
+	function shimPeerConnection(window, browserDetails) {
+	  if (typeof window !== 'object' ||
+	      !(window.RTCPeerConnection || window.mozRTCPeerConnection)) {
+	    return; // probably media.peerconnection.enabled=false in about:config
+	  }
+	  if (!window.RTCPeerConnection && window.mozRTCPeerConnection) {
+	    // very basic support for old versions.
+	    window.RTCPeerConnection = window.mozRTCPeerConnection;
+	  }
+
+	  if (browserDetails.version < 53) {
+	    // shim away need for obsolete RTCIceCandidate/RTCSessionDescription.
+	    ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
+	        .forEach(function(method) {
+	          const nativeMethod = window.RTCPeerConnection.prototype[method];
+	          const methodObj = {[method]() {
+	            arguments[0] = new ((method === 'addIceCandidate') ?
+	                window.RTCIceCandidate :
+	                window.RTCSessionDescription)(arguments[0]);
+	            return nativeMethod.apply(this, arguments);
+	          }};
+	          window.RTCPeerConnection.prototype[method] = methodObj[method];
+	        });
+	  }
+
+	  const modernStatsTypes = {
+	    inboundrtp: 'inbound-rtp',
+	    outboundrtp: 'outbound-rtp',
+	    candidatepair: 'candidate-pair',
+	    localcandidate: 'local-candidate',
+	    remotecandidate: 'remote-candidate'
+	  };
+
+	  const nativeGetStats = window.RTCPeerConnection.prototype.getStats;
+	  window.RTCPeerConnection.prototype.getStats = function getStats() {
+	    const [selector, onSucc, onErr] = arguments;
+	    return nativeGetStats.apply(this, [selector || null])
+	      .then(stats => {
+	        if (browserDetails.version < 53 && !onSucc) {
+	          // Shim only promise getStats with spec-hyphens in type names
+	          // Leave callback version alone; misc old uses of forEach before Map
+	          try {
+	            stats.forEach(stat => {
+	              stat.type = modernStatsTypes[stat.type] || stat.type;
+	            });
+	          } catch (e) {
+	            if (e.name !== 'TypeError') {
+	              throw e;
+	            }
+	            // Avoid TypeError: "type" is read-only, in old versions. 34-43ish
+	            stats.forEach((stat, i) => {
+	              stats.set(i, Object.assign({}, stat, {
+	                type: modernStatsTypes[stat.type] || stat.type
+	              }));
+	            });
+	          }
+	        }
+	        return stats;
+	      })
+	      .then(onSucc, onErr);
+	  };
+	}
+
+	function shimSenderGetStats(window) {
+	  if (!(typeof window === 'object' && window.RTCPeerConnection &&
+	      window.RTCRtpSender)) {
+	    return;
+	  }
+	  if (window.RTCRtpSender && 'getStats' in window.RTCRtpSender.prototype) {
+	    return;
+	  }
+	  const origGetSenders = window.RTCPeerConnection.prototype.getSenders;
+	  if (origGetSenders) {
+	    window.RTCPeerConnection.prototype.getSenders = function getSenders() {
+	      const senders = origGetSenders.apply(this, []);
+	      senders.forEach(sender => sender._pc = this);
+	      return senders;
+	    };
+	  }
+
+	  const origAddTrack = window.RTCPeerConnection.prototype.addTrack;
+	  if (origAddTrack) {
+	    window.RTCPeerConnection.prototype.addTrack = function addTrack() {
+	      const sender = origAddTrack.apply(this, arguments);
+	      sender._pc = this;
+	      return sender;
+	    };
+	  }
+	  window.RTCRtpSender.prototype.getStats = function getStats() {
+	    return this.track ? this._pc.getStats(this.track) :
+	        Promise.resolve(new Map());
+	  };
+	}
+
+	function shimReceiverGetStats(window) {
+	  if (!(typeof window === 'object' && window.RTCPeerConnection &&
+	      window.RTCRtpSender)) {
+	    return;
+	  }
+	  if (window.RTCRtpSender && 'getStats' in window.RTCRtpReceiver.prototype) {
+	    return;
+	  }
+	  const origGetReceivers = window.RTCPeerConnection.prototype.getReceivers;
+	  if (origGetReceivers) {
+	    window.RTCPeerConnection.prototype.getReceivers = function getReceivers() {
+	      const receivers = origGetReceivers.apply(this, []);
+	      receivers.forEach(receiver => receiver._pc = this);
+	      return receivers;
+	    };
+	  }
+	  wrapPeerConnectionEvent(window, 'track', e => {
+	    e.receiver._pc = e.srcElement;
+	    return e;
+	  });
+	  window.RTCRtpReceiver.prototype.getStats = function getStats() {
+	    return this._pc.getStats(this.track);
+	  };
+	}
+
+	function shimRemoveStream(window) {
+	  if (!window.RTCPeerConnection ||
+	      'removeStream' in window.RTCPeerConnection.prototype) {
+	    return;
+	  }
+	  window.RTCPeerConnection.prototype.removeStream =
+	    function removeStream(stream) {
+	      deprecated('removeStream', 'removeTrack');
+	      this.getSenders().forEach(sender => {
+	        if (sender.track && stream.getTracks().includes(sender.track)) {
+	          this.removeTrack(sender);
+	        }
+	      });
+	    };
+	}
+
+	function shimRTCDataChannel(window) {
+	  // rename DataChannel to RTCDataChannel (native fix in FF60):
+	  // https://bugzilla.mozilla.org/show_bug.cgi?id=1173851
+	  if (window.DataChannel && !window.RTCDataChannel) {
+	    window.RTCDataChannel = window.DataChannel;
+	  }
+	}
+
+	function shimAddTransceiver(window) {
+	  // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
+	  // Firefox ignores the init sendEncodings options passed to addTransceiver
+	  // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
+	  if (!(typeof window === 'object' && window.RTCPeerConnection)) {
+	    return;
+	  }
+	  const origAddTransceiver = window.RTCPeerConnection.prototype.addTransceiver;
+	  if (origAddTransceiver) {
+	    window.RTCPeerConnection.prototype.addTransceiver =
+	      function addTransceiver() {
+	        this.setParametersPromises = [];
+	        const initParameters = arguments[1];
+	        const shouldPerformCheck = initParameters &&
+	                                  'sendEncodings' in initParameters;
+	        if (shouldPerformCheck) {
+	          // If sendEncodings params are provided, validate grammar
+	          initParameters.sendEncodings.forEach((encodingParam) => {
+	            if ('rid' in encodingParam) {
+	              const ridRegex = /^[a-z0-9]{0,16}$/i;
+	              if (!ridRegex.test(encodingParam.rid)) {
+	                throw new TypeError('Invalid RID value provided.');
+	              }
+	            }
+	            if ('scaleResolutionDownBy' in encodingParam) {
+	              if (!(parseFloat(encodingParam.scaleResolutionDownBy) >= 1.0)) {
+	                throw new RangeError('scale_resolution_down_by must be >= 1.0');
+	              }
+	            }
+	            if ('maxFramerate' in encodingParam) {
+	              if (!(parseFloat(encodingParam.maxFramerate) >= 0)) {
+	                throw new RangeError('max_framerate must be >= 0.0');
+	              }
+	            }
+	          });
+	        }
+	        const transceiver = origAddTransceiver.apply(this, arguments);
+	        if (shouldPerformCheck) {
+	          // Check if the init options were applied. If not we do this in an
+	          // asynchronous way and save the promise reference in a global object.
+	          // This is an ugly hack, but at the same time is way more robust than
+	          // checking the sender parameters before and after the createOffer
+	          // Also note that after the createoffer we are not 100% sure that
+	          // the params were asynchronously applied so we might miss the
+	          // opportunity to recreate offer.
+	          const {sender} = transceiver;
+	          const params = sender.getParameters();
+	          if (!('encodings' in params) ||
+	              // Avoid being fooled by patched getParameters() below.
+	              (params.encodings.length === 1 &&
+	               Object.keys(params.encodings[0]).length === 0)) {
+	            params.encodings = initParameters.sendEncodings;
+	            sender.sendEncodings = initParameters.sendEncodings;
+	            this.setParametersPromises.push(sender.setParameters(params)
+	              .then(() => {
+	                delete sender.sendEncodings;
+	              }).catch(() => {
+	                delete sender.sendEncodings;
+	              })
+	            );
+	          }
+	        }
+	        return transceiver;
+	      };
+	  }
+	}
+
+	function shimGetParameters(window) {
+	  if (!(typeof window === 'object' && window.RTCRtpSender)) {
+	    return;
+	  }
+	  const origGetParameters = window.RTCRtpSender.prototype.getParameters;
+	  if (origGetParameters) {
+	    window.RTCRtpSender.prototype.getParameters =
+	      function getParameters() {
+	        const params = origGetParameters.apply(this, arguments);
+	        if (!('encodings' in params)) {
+	          params.encodings = [].concat(this.sendEncodings || [{}]);
+	        }
+	        return params;
+	      };
+	  }
+	}
+
+	function shimCreateOffer(window) {
+	  // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
+	  // Firefox ignores the init sendEncodings options passed to addTransceiver
+	  // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
+	  if (!(typeof window === 'object' && window.RTCPeerConnection)) {
+	    return;
+	  }
+	  const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
+	  window.RTCPeerConnection.prototype.createOffer = function createOffer() {
+	    if (this.setParametersPromises && this.setParametersPromises.length) {
+	      return Promise.all(this.setParametersPromises)
+	      .then(() => {
+	        return origCreateOffer.apply(this, arguments);
+	      })
+	      .finally(() => {
+	        this.setParametersPromises = [];
+	      });
+	    }
+	    return origCreateOffer.apply(this, arguments);
+	  };
+	}
+
+	function shimCreateAnswer(window) {
+	  // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
+	  // Firefox ignores the init sendEncodings options passed to addTransceiver
+	  // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
+	  if (!(typeof window === 'object' && window.RTCPeerConnection)) {
+	    return;
+	  }
+	  const origCreateAnswer = window.RTCPeerConnection.prototype.createAnswer;
+	  window.RTCPeerConnection.prototype.createAnswer = function createAnswer() {
+	    if (this.setParametersPromises && this.setParametersPromises.length) {
+	      return Promise.all(this.setParametersPromises)
+	      .then(() => {
+	        return origCreateAnswer.apply(this, arguments);
+	      })
+	      .finally(() => {
+	        this.setParametersPromises = [];
+	      });
+	    }
+	    return origCreateAnswer.apply(this, arguments);
+	  };
+	}
+
+	var firefoxShim = /*#__PURE__*/Object.freeze({
+		__proto__: null,
+		shimOnTrack: shimOnTrack,
+		shimPeerConnection: shimPeerConnection,
+		shimSenderGetStats: shimSenderGetStats,
+		shimReceiverGetStats: shimReceiverGetStats,
+		shimRemoveStream: shimRemoveStream,
+		shimRTCDataChannel: shimRTCDataChannel,
+		shimAddTransceiver: shimAddTransceiver,
+		shimGetParameters: shimGetParameters,
+		shimCreateOffer: shimCreateOffer,
+		shimCreateAnswer: shimCreateAnswer,
+		shimGetUserMedia: shimGetUserMedia$1,
+		shimGetDisplayMedia: shimGetDisplayMedia
+	});
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimLocalStreamsAPI(window) {
+	  if (typeof window !== 'object' || !window.RTCPeerConnection) {
+	    return;
+	  }
+	  if (!('getLocalStreams' in window.RTCPeerConnection.prototype)) {
+	    window.RTCPeerConnection.prototype.getLocalStreams =
+	      function getLocalStreams() {
+	        if (!this._localStreams) {
+	          this._localStreams = [];
+	        }
+	        return this._localStreams;
+	      };
+	  }
+	  if (!('addStream' in window.RTCPeerConnection.prototype)) {
+	    const _addTrack = window.RTCPeerConnection.prototype.addTrack;
+	    window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
+	      if (!this._localStreams) {
+	        this._localStreams = [];
+	      }
+	      if (!this._localStreams.includes(stream)) {
+	        this._localStreams.push(stream);
+	      }
+	      // Try to emulate Chrome's behaviour of adding in audio-video order.
+	      // Safari orders by track id.
+	      stream.getAudioTracks().forEach(track => _addTrack.call(this, track,
+	        stream));
+	      stream.getVideoTracks().forEach(track => _addTrack.call(this, track,
+	        stream));
+	    };
+
+	    window.RTCPeerConnection.prototype.addTrack =
+	      function addTrack(track, ...streams) {
+	        if (streams) {
+	          streams.forEach((stream) => {
+	            if (!this._localStreams) {
+	              this._localStreams = [stream];
+	            } else if (!this._localStreams.includes(stream)) {
+	              this._localStreams.push(stream);
+	            }
+	          });
+	        }
+	        return _addTrack.apply(this, arguments);
+	      };
+	  }
+	  if (!('removeStream' in window.RTCPeerConnection.prototype)) {
+	    window.RTCPeerConnection.prototype.removeStream =
+	      function removeStream(stream) {
+	        if (!this._localStreams) {
+	          this._localStreams = [];
+	        }
+	        const index = this._localStreams.indexOf(stream);
+	        if (index === -1) {
+	          return;
+	        }
+	        this._localStreams.splice(index, 1);
+	        const tracks = stream.getTracks();
+	        this.getSenders().forEach(sender => {
+	          if (tracks.includes(sender.track)) {
+	            this.removeTrack(sender);
+	          }
+	        });
+	      };
+	  }
+	}
+
+	function shimRemoteStreamsAPI(window) {
+	  if (typeof window !== 'object' || !window.RTCPeerConnection) {
+	    return;
+	  }
+	  if (!('getRemoteStreams' in window.RTCPeerConnection.prototype)) {
+	    window.RTCPeerConnection.prototype.getRemoteStreams =
+	      function getRemoteStreams() {
+	        return this._remoteStreams ? this._remoteStreams : [];
+	      };
+	  }
+	  if (!('onaddstream' in window.RTCPeerConnection.prototype)) {
+	    Object.defineProperty(window.RTCPeerConnection.prototype, 'onaddstream', {
+	      get() {
+	        return this._onaddstream;
+	      },
+	      set(f) {
+	        if (this._onaddstream) {
+	          this.removeEventListener('addstream', this._onaddstream);
+	          this.removeEventListener('track', this._onaddstreampoly);
+	        }
+	        this.addEventListener('addstream', this._onaddstream = f);
+	        this.addEventListener('track', this._onaddstreampoly = (e) => {
+	          e.streams.forEach(stream => {
+	            if (!this._remoteStreams) {
+	              this._remoteStreams = [];
+	            }
+	            if (this._remoteStreams.includes(stream)) {
+	              return;
+	            }
+	            this._remoteStreams.push(stream);
+	            const event = new Event('addstream');
+	            event.stream = stream;
+	            this.dispatchEvent(event);
+	          });
+	        });
+	      }
+	    });
+	    const origSetRemoteDescription =
+	      window.RTCPeerConnection.prototype.setRemoteDescription;
+	    window.RTCPeerConnection.prototype.setRemoteDescription =
+	      function setRemoteDescription() {
+	        const pc = this;
+	        if (!this._onaddstreampoly) {
+	          this.addEventListener('track', this._onaddstreampoly = function(e) {
+	            e.streams.forEach(stream => {
+	              if (!pc._remoteStreams) {
+	                pc._remoteStreams = [];
+	              }
+	              if (pc._remoteStreams.indexOf(stream) >= 0) {
+	                return;
+	              }
+	              pc._remoteStreams.push(stream);
+	              const event = new Event('addstream');
+	              event.stream = stream;
+	              pc.dispatchEvent(event);
+	            });
+	          });
+	        }
+	        return origSetRemoteDescription.apply(pc, arguments);
+	      };
+	  }
+	}
+
+	function shimCallbacksAPI(window) {
+	  if (typeof window !== 'object' || !window.RTCPeerConnection) {
+	    return;
+	  }
+	  const prototype = window.RTCPeerConnection.prototype;
+	  const origCreateOffer = prototype.createOffer;
+	  const origCreateAnswer = prototype.createAnswer;
+	  const setLocalDescription = prototype.setLocalDescription;
+	  const setRemoteDescription = prototype.setRemoteDescription;
+	  const addIceCandidate = prototype.addIceCandidate;
+
+	  prototype.createOffer =
+	    function createOffer(successCallback, failureCallback) {
+	      const options = (arguments.length >= 2) ? arguments[2] : arguments[0];
+	      const promise = origCreateOffer.apply(this, [options]);
+	      if (!failureCallback) {
+	        return promise;
+	      }
+	      promise.then(successCallback, failureCallback);
+	      return Promise.resolve();
+	    };
+
+	  prototype.createAnswer =
+	    function createAnswer(successCallback, failureCallback) {
+	      const options = (arguments.length >= 2) ? arguments[2] : arguments[0];
+	      const promise = origCreateAnswer.apply(this, [options]);
+	      if (!failureCallback) {
+	        return promise;
+	      }
+	      promise.then(successCallback, failureCallback);
+	      return Promise.resolve();
+	    };
+
+	  let withCallback = function(description, successCallback, failureCallback) {
+	    const promise = setLocalDescription.apply(this, [description]);
+	    if (!failureCallback) {
+	      return promise;
+	    }
+	    promise.then(successCallback, failureCallback);
+	    return Promise.resolve();
+	  };
+	  prototype.setLocalDescription = withCallback;
+
+	  withCallback = function(description, successCallback, failureCallback) {
+	    const promise = setRemoteDescription.apply(this, [description]);
+	    if (!failureCallback) {
+	      return promise;
+	    }
+	    promise.then(successCallback, failureCallback);
+	    return Promise.resolve();
+	  };
+	  prototype.setRemoteDescription = withCallback;
+
+	  withCallback = function(candidate, successCallback, failureCallback) {
+	    const promise = addIceCandidate.apply(this, [candidate]);
+	    if (!failureCallback) {
+	      return promise;
+	    }
+	    promise.then(successCallback, failureCallback);
+	    return Promise.resolve();
+	  };
+	  prototype.addIceCandidate = withCallback;
+	}
+
+	function shimGetUserMedia(window) {
+	  const navigator = window && window.navigator;
+
+	  if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
+	    // shim not needed in Safari 12.1
+	    const mediaDevices = navigator.mediaDevices;
+	    const _getUserMedia = mediaDevices.getUserMedia.bind(mediaDevices);
+	    navigator.mediaDevices.getUserMedia = (constraints) => {
+	      return _getUserMedia(shimConstraints(constraints));
+	    };
+	  }
+
+	  if (!navigator.getUserMedia && navigator.mediaDevices &&
+	    navigator.mediaDevices.getUserMedia) {
+	    navigator.getUserMedia = function getUserMedia(constraints, cb, errcb) {
+	      navigator.mediaDevices.getUserMedia(constraints)
+	      .then(cb, errcb);
+	    }.bind(navigator);
+	  }
+	}
+
+	function shimConstraints(constraints) {
+	  if (constraints && constraints.video !== undefined) {
+	    return Object.assign({},
+	      constraints,
+	      {video: compactObject(constraints.video)}
+	    );
+	  }
+
+	  return constraints;
+	}
+
+	function shimRTCIceServerUrls(window) {
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+	  // migrate from non-spec RTCIceServer.url to RTCIceServer.urls
+	  const OrigPeerConnection = window.RTCPeerConnection;
+	  window.RTCPeerConnection =
+	    function RTCPeerConnection(pcConfig, pcConstraints) {
+	      if (pcConfig && pcConfig.iceServers) {
+	        const newIceServers = [];
+	        for (let i = 0; i < pcConfig.iceServers.length; i++) {
+	          let server = pcConfig.iceServers[i];
+	          if (!server.hasOwnProperty('urls') &&
+	              server.hasOwnProperty('url')) {
+	            deprecated('RTCIceServer.url', 'RTCIceServer.urls');
+	            server = JSON.parse(JSON.stringify(server));
+	            server.urls = server.url;
+	            delete server.url;
+	            newIceServers.push(server);
+	          } else {
+	            newIceServers.push(pcConfig.iceServers[i]);
+	          }
+	        }
+	        pcConfig.iceServers = newIceServers;
+	      }
+	      return new OrigPeerConnection(pcConfig, pcConstraints);
+	    };
+	  window.RTCPeerConnection.prototype = OrigPeerConnection.prototype;
+	  // wrap static methods. Currently just generateCertificate.
+	  if ('generateCertificate' in OrigPeerConnection) {
+	    Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
+	      get() {
+	        return OrigPeerConnection.generateCertificate;
+	      }
+	    });
+	  }
+	}
+
+	function shimTrackEventTransceiver(window) {
+	  // Add event.transceiver member over deprecated event.receiver
+	  if (typeof window === 'object' && window.RTCTrackEvent &&
+	      'receiver' in window.RTCTrackEvent.prototype &&
+	      !('transceiver' in window.RTCTrackEvent.prototype)) {
+	    Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
+	      get() {
+	        return {receiver: this.receiver};
+	      }
+	    });
+	  }
+	}
+
+	function shimCreateOfferLegacy(window) {
+	  const origCreateOffer = window.RTCPeerConnection.prototype.createOffer;
+	  window.RTCPeerConnection.prototype.createOffer =
+	    function createOffer(offerOptions) {
+	      if (offerOptions) {
+	        if (typeof offerOptions.offerToReceiveAudio !== 'undefined') {
+	          // support bit values
+	          offerOptions.offerToReceiveAudio =
+	            !!offerOptions.offerToReceiveAudio;
+	        }
+	        const audioTransceiver = this.getTransceivers().find(transceiver =>
+	          transceiver.receiver.track.kind === 'audio');
+	        if (offerOptions.offerToReceiveAudio === false && audioTransceiver) {
+	          if (audioTransceiver.direction === 'sendrecv') {
+	            if (audioTransceiver.setDirection) {
+	              audioTransceiver.setDirection('sendonly');
+	            } else {
+	              audioTransceiver.direction = 'sendonly';
+	            }
+	          } else if (audioTransceiver.direction === 'recvonly') {
+	            if (audioTransceiver.setDirection) {
+	              audioTransceiver.setDirection('inactive');
+	            } else {
+	              audioTransceiver.direction = 'inactive';
+	            }
+	          }
+	        } else if (offerOptions.offerToReceiveAudio === true &&
+	            !audioTransceiver) {
+	          this.addTransceiver('audio');
+	        }
+
+	        if (typeof offerOptions.offerToReceiveVideo !== 'undefined') {
+	          // support bit values
+	          offerOptions.offerToReceiveVideo =
+	            !!offerOptions.offerToReceiveVideo;
+	        }
+	        const videoTransceiver = this.getTransceivers().find(transceiver =>
+	          transceiver.receiver.track.kind === 'video');
+	        if (offerOptions.offerToReceiveVideo === false && videoTransceiver) {
+	          if (videoTransceiver.direction === 'sendrecv') {
+	            if (videoTransceiver.setDirection) {
+	              videoTransceiver.setDirection('sendonly');
+	            } else {
+	              videoTransceiver.direction = 'sendonly';
+	            }
+	          } else if (videoTransceiver.direction === 'recvonly') {
+	            if (videoTransceiver.setDirection) {
+	              videoTransceiver.setDirection('inactive');
+	            } else {
+	              videoTransceiver.direction = 'inactive';
+	            }
+	          }
+	        } else if (offerOptions.offerToReceiveVideo === true &&
+	            !videoTransceiver) {
+	          this.addTransceiver('video');
+	        }
+	      }
+	      return origCreateOffer.apply(this, arguments);
+	    };
+	}
+
+	function shimAudioContext(window) {
+	  if (typeof window !== 'object' || window.AudioContext) {
+	    return;
+	  }
+	  window.AudioContext = window.webkitAudioContext;
+	}
+
+	var safariShim = /*#__PURE__*/Object.freeze({
+		__proto__: null,
+		shimLocalStreamsAPI: shimLocalStreamsAPI,
+		shimRemoteStreamsAPI: shimRemoteStreamsAPI,
+		shimCallbacksAPI: shimCallbacksAPI,
+		shimGetUserMedia: shimGetUserMedia,
+		shimConstraints: shimConstraints,
+		shimRTCIceServerUrls: shimRTCIceServerUrls,
+		shimTrackEventTransceiver: shimTrackEventTransceiver,
+		shimCreateOfferLegacy: shimCreateOfferLegacy,
+		shimAudioContext: shimAudioContext
+	});
+
+	/*
+	 *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	function shimRTCIceCandidate(window) {
+	  // foundation is arbitrarily chosen as an indicator for full support for
+	  // https://w3c.github.io/webrtc-pc/#rtcicecandidate-interface
+	  if (!window.RTCIceCandidate || (window.RTCIceCandidate && 'foundation' in
+	      window.RTCIceCandidate.prototype)) {
+	    return;
+	  }
+
+	  const NativeRTCIceCandidate = window.RTCIceCandidate;
+	  window.RTCIceCandidate = function RTCIceCandidate(args) {
+	    // Remove the a= which shouldn't be part of the candidate string.
+	    if (typeof args === 'object' && args.candidate &&
+	        args.candidate.indexOf('a=') === 0) {
+	      args = JSON.parse(JSON.stringify(args));
+	      args.candidate = args.candidate.substr(2);
+	    }
+
+	    if (args.candidate && args.candidate.length) {
+	      // Augment the native candidate with the parsed fields.
+	      const nativeCandidate = new NativeRTCIceCandidate(args);
+	      const parsedCandidate = sdp.parseCandidate(args.candidate);
+	      const augmentedCandidate = Object.assign(nativeCandidate,
+	          parsedCandidate);
+
+	      // Add a serializer that does not serialize the extra attributes.
+	      augmentedCandidate.toJSON = function toJSON() {
+	        return {
+	          candidate: augmentedCandidate.candidate,
+	          sdpMid: augmentedCandidate.sdpMid,
+	          sdpMLineIndex: augmentedCandidate.sdpMLineIndex,
+	          usernameFragment: augmentedCandidate.usernameFragment,
+	        };
+	      };
+	      return augmentedCandidate;
+	    }
+	    return new NativeRTCIceCandidate(args);
+	  };
+	  window.RTCIceCandidate.prototype = NativeRTCIceCandidate.prototype;
+
+	  // Hook up the augmented candidate in onicecandidate and
+	  // addEventListener('icecandidate', ...)
+	  wrapPeerConnectionEvent(window, 'icecandidate', e => {
+	    if (e.candidate) {
+	      Object.defineProperty(e, 'candidate', {
+	        value: new window.RTCIceCandidate(e.candidate),
+	        writable: 'false'
+	      });
+	    }
+	    return e;
+	  });
+	}
+
+	function shimMaxMessageSize(window, browserDetails) {
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+
+	  if (!('sctp' in window.RTCPeerConnection.prototype)) {
+	    Object.defineProperty(window.RTCPeerConnection.prototype, 'sctp', {
+	      get() {
+	        return typeof this._sctp === 'undefined' ? null : this._sctp;
+	      }
+	    });
+	  }
+
+	  const sctpInDescription = function(description) {
+	    if (!description || !description.sdp) {
+	      return false;
+	    }
+	    const sections = sdp.splitSections(description.sdp);
+	    sections.shift();
+	    return sections.some(mediaSection => {
+	      const mLine = sdp.parseMLine(mediaSection);
+	      return mLine && mLine.kind === 'application'
+	          && mLine.protocol.indexOf('SCTP') !== -1;
+	    });
+	  };
+
+	  const getRemoteFirefoxVersion = function(description) {
+	    // TODO: Is there a better solution for detecting Firefox?
+	    const match = description.sdp.match(/mozilla...THIS_IS_SDPARTA-(\d+)/);
+	    if (match === null || match.length < 2) {
+	      return -1;
+	    }
+	    const version = parseInt(match[1], 10);
+	    // Test for NaN (yes, this is ugly)
+	    return version !== version ? -1 : version;
+	  };
+
+	  const getCanSendMaxMessageSize = function(remoteIsFirefox) {
+	    // Every implementation we know can send at least 64 KiB.
+	    // Note: Although Chrome is technically able to send up to 256 KiB, the
+	    //       data does not reach the other peer reliably.
+	    //       See: https://bugs.chromium.org/p/webrtc/issues/detail?id=8419
+	    let canSendMaxMessageSize = 65536;
+	    if (browserDetails.browser === 'firefox') {
+	      if (browserDetails.version < 57) {
+	        if (remoteIsFirefox === -1) {
+	          // FF < 57 will send in 16 KiB chunks using the deprecated PPID
+	          // fragmentation.
+	          canSendMaxMessageSize = 16384;
+	        } else {
+	          // However, other FF (and RAWRTC) can reassemble PPID-fragmented
+	          // messages. Thus, supporting ~2 GiB when sending.
+	          canSendMaxMessageSize = 2147483637;
+	        }
+	      } else if (browserDetails.version < 60) {
+	        // Currently, all FF >= 57 will reset the remote maximum message size
+	        // to the default value when a data channel is created at a later
+	        // stage. :(
+	        // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
+	        canSendMaxMessageSize =
+	          browserDetails.version === 57 ? 65535 : 65536;
+	      } else {
+	        // FF >= 60 supports sending ~2 GiB
+	        canSendMaxMessageSize = 2147483637;
+	      }
+	    }
+	    return canSendMaxMessageSize;
+	  };
+
+	  const getMaxMessageSize = function(description, remoteIsFirefox) {
+	    // Note: 65536 bytes is the default value from the SDP spec. Also,
+	    //       every implementation we know supports receiving 65536 bytes.
+	    let maxMessageSize = 65536;
+
+	    // FF 57 has a slightly incorrect default remote max message size, so
+	    // we need to adjust it here to avoid a failure when sending.
+	    // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1425697
+	    if (browserDetails.browser === 'firefox'
+	         && browserDetails.version === 57) {
+	      maxMessageSize = 65535;
+	    }
+
+	    const match = sdp.matchPrefix(description.sdp,
+	      'a=max-message-size:');
+	    if (match.length > 0) {
+	      maxMessageSize = parseInt(match[0].substr(19), 10);
+	    } else if (browserDetails.browser === 'firefox' &&
+	                remoteIsFirefox !== -1) {
+	      // If the maximum message size is not present in the remote SDP and
+	      // both local and remote are Firefox, the remote peer can receive
+	      // ~2 GiB.
+	      maxMessageSize = 2147483637;
+	    }
+	    return maxMessageSize;
+	  };
+
+	  const origSetRemoteDescription =
+	      window.RTCPeerConnection.prototype.setRemoteDescription;
+	  window.RTCPeerConnection.prototype.setRemoteDescription =
+	    function setRemoteDescription() {
+	      this._sctp = null;
+	      // Chrome decided to not expose .sctp in plan-b mode.
+	      // As usual, adapter.js has to do an 'ugly worakaround'
+	      // to cover up the mess.
+	      if (browserDetails.browser === 'chrome' && browserDetails.version >= 76) {
+	        const {sdpSemantics} = this.getConfiguration();
+	        if (sdpSemantics === 'plan-b') {
+	          Object.defineProperty(this, 'sctp', {
+	            get() {
+	              return typeof this._sctp === 'undefined' ? null : this._sctp;
+	            },
+	            enumerable: true,
+	            configurable: true,
+	          });
+	        }
+	      }
+
+	      if (sctpInDescription(arguments[0])) {
+	        // Check if the remote is FF.
+	        const isFirefox = getRemoteFirefoxVersion(arguments[0]);
+
+	        // Get the maximum message size the local peer is capable of sending
+	        const canSendMMS = getCanSendMaxMessageSize(isFirefox);
+
+	        // Get the maximum message size of the remote peer.
+	        const remoteMMS = getMaxMessageSize(arguments[0], isFirefox);
+
+	        // Determine final maximum message size
+	        let maxMessageSize;
+	        if (canSendMMS === 0 && remoteMMS === 0) {
+	          maxMessageSize = Number.POSITIVE_INFINITY;
+	        } else if (canSendMMS === 0 || remoteMMS === 0) {
+	          maxMessageSize = Math.max(canSendMMS, remoteMMS);
+	        } else {
+	          maxMessageSize = Math.min(canSendMMS, remoteMMS);
+	        }
+
+	        // Create a dummy RTCSctpTransport object and the 'maxMessageSize'
+	        // attribute.
+	        const sctp = {};
+	        Object.defineProperty(sctp, 'maxMessageSize', {
+	          get() {
+	            return maxMessageSize;
+	          }
+	        });
+	        this._sctp = sctp;
+	      }
+
+	      return origSetRemoteDescription.apply(this, arguments);
+	    };
+	}
+
+	function shimSendThrowTypeError(window) {
+	  if (!(window.RTCPeerConnection &&
+	      'createDataChannel' in window.RTCPeerConnection.prototype)) {
+	    return;
+	  }
+
+	  // Note: Although Firefox >= 57 has a native implementation, the maximum
+	  //       message size can be reset for all data channels at a later stage.
+	  //       See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
+
+	  function wrapDcSend(dc, pc) {
+	    const origDataChannelSend = dc.send;
+	    dc.send = function send() {
+	      const data = arguments[0];
+	      const length = data.length || data.size || data.byteLength;
+	      if (dc.readyState === 'open' &&
+	          pc.sctp && length > pc.sctp.maxMessageSize) {
+	        throw new TypeError('Message too large (can send a maximum of ' +
+	          pc.sctp.maxMessageSize + ' bytes)');
+	      }
+	      return origDataChannelSend.apply(dc, arguments);
+	    };
+	  }
+	  const origCreateDataChannel =
+	    window.RTCPeerConnection.prototype.createDataChannel;
+	  window.RTCPeerConnection.prototype.createDataChannel =
+	    function createDataChannel() {
+	      const dataChannel = origCreateDataChannel.apply(this, arguments);
+	      wrapDcSend(dataChannel, this);
+	      return dataChannel;
+	    };
+	  wrapPeerConnectionEvent(window, 'datachannel', e => {
+	    wrapDcSend(e.channel, e.target);
+	    return e;
+	  });
+	}
+
+
+	/* shims RTCConnectionState by pretending it is the same as iceConnectionState.
+	 * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
+	 * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
+	 * since DTLS failures would be hidden. See
+	 * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
+	 * for the Firefox tracking bug.
+	 */
+	function shimConnectionState(window) {
+	  if (!window.RTCPeerConnection ||
+	      'connectionState' in window.RTCPeerConnection.prototype) {
+	    return;
+	  }
+	  const proto = window.RTCPeerConnection.prototype;
+	  Object.defineProperty(proto, 'connectionState', {
+	    get() {
+	      return {
+	        completed: 'connected',
+	        checking: 'connecting'
+	      }[this.iceConnectionState] || this.iceConnectionState;
+	    },
+	    enumerable: true,
+	    configurable: true
+	  });
+	  Object.defineProperty(proto, 'onconnectionstatechange', {
+	    get() {
+	      return this._onconnectionstatechange || null;
+	    },
+	    set(cb) {
+	      if (this._onconnectionstatechange) {
+	        this.removeEventListener('connectionstatechange',
+	            this._onconnectionstatechange);
+	        delete this._onconnectionstatechange;
+	      }
+	      if (cb) {
+	        this.addEventListener('connectionstatechange',
+	            this._onconnectionstatechange = cb);
+	      }
+	    },
+	    enumerable: true,
+	    configurable: true
+	  });
+
+	  ['setLocalDescription', 'setRemoteDescription'].forEach((method) => {
+	    const origMethod = proto[method];
+	    proto[method] = function() {
+	      if (!this._connectionstatechangepoly) {
+	        this._connectionstatechangepoly = e => {
+	          const pc = e.target;
+	          if (pc._lastConnectionState !== pc.connectionState) {
+	            pc._lastConnectionState = pc.connectionState;
+	            const newEvent = new Event('connectionstatechange', e);
+	            pc.dispatchEvent(newEvent);
+	          }
+	          return e;
+	        };
+	        this.addEventListener('iceconnectionstatechange',
+	          this._connectionstatechangepoly);
+	      }
+	      return origMethod.apply(this, arguments);
+	    };
+	  });
+	}
+
+	function removeExtmapAllowMixed(window, browserDetails) {
+	  /* remove a=extmap-allow-mixed for webrtc.org < M71 */
+	  if (!window.RTCPeerConnection) {
+	    return;
+	  }
+	  if (browserDetails.browser === 'chrome' && browserDetails.version >= 71) {
+	    return;
+	  }
+	  if (browserDetails.browser === 'safari' && browserDetails.version >= 605) {
+	    return;
+	  }
+	  const nativeSRD = window.RTCPeerConnection.prototype.setRemoteDescription;
+	  window.RTCPeerConnection.prototype.setRemoteDescription =
+	  function setRemoteDescription(desc) {
+	    if (desc && desc.sdp && desc.sdp.indexOf('\na=extmap-allow-mixed') !== -1) {
+	      const sdp = desc.sdp.split('\n').filter((line) => {
+	        return line.trim() !== 'a=extmap-allow-mixed';
+	      }).join('\n');
+	      // Safari enforces read-only-ness of RTCSessionDescription fields.
+	      if (window.RTCSessionDescription &&
+	          desc instanceof window.RTCSessionDescription) {
+	        arguments[0] = new window.RTCSessionDescription({
+	          type: desc.type,
+	          sdp,
+	        });
+	      } else {
+	        desc.sdp = sdp;
+	      }
+	    }
+	    return nativeSRD.apply(this, arguments);
+	  };
+	}
+
+	function shimAddIceCandidateNullOrEmpty(window, browserDetails) {
+	  // Support for addIceCandidate(null or undefined)
+	  // as well as addIceCandidate({candidate: "", ...})
+	  // https://bugs.chromium.org/p/chromium/issues/detail?id=978582
+	  // Note: must be called before other polyfills which change the signature.
+	  if (!(window.RTCPeerConnection && window.RTCPeerConnection.prototype)) {
+	    return;
+	  }
+	  const nativeAddIceCandidate =
+	      window.RTCPeerConnection.prototype.addIceCandidate;
+	  if (!nativeAddIceCandidate || nativeAddIceCandidate.length === 0) {
+	    return;
+	  }
+	  window.RTCPeerConnection.prototype.addIceCandidate =
+	    function addIceCandidate() {
+	      if (!arguments[0]) {
+	        if (arguments[1]) {
+	          arguments[1].apply(null);
+	        }
+	        return Promise.resolve();
+	      }
+	      // Firefox 68+ emits and processes {candidate: "", ...}, ignore
+	      // in older versions.
+	      // Native support for ignoring exists for Chrome M77+.
+	      // Safari ignores as well, exact version unknown but works in the same
+	      // version that also ignores addIceCandidate(null).
+	      if (((browserDetails.browser === 'chrome' && browserDetails.version < 78)
+	           || (browserDetails.browser === 'firefox'
+	               && browserDetails.version < 68)
+	           || (browserDetails.browser === 'safari'))
+	          && arguments[0] && arguments[0].candidate === '') {
+	        return Promise.resolve();
+	      }
+	      return nativeAddIceCandidate.apply(this, arguments);
+	    };
+	}
+
+	var commonShim = /*#__PURE__*/Object.freeze({
+		__proto__: null,
+		shimRTCIceCandidate: shimRTCIceCandidate,
+		shimMaxMessageSize: shimMaxMessageSize,
+		shimSendThrowTypeError: shimSendThrowTypeError,
+		shimConnectionState: shimConnectionState,
+		removeExtmapAllowMixed: removeExtmapAllowMixed,
+		shimAddIceCandidateNullOrEmpty: shimAddIceCandidateNullOrEmpty
+	});
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	// Shimming starts here.
+	function adapterFactory({window} = {}, options = {
+	  shimChrome: true,
+	  shimFirefox: true,
+	  shimEdge: true,
+	  shimSafari: true,
+	}) {
+	  // Utils.
+	  const logging = log$1;
+	  const browserDetails = detectBrowser(window);
+
+	  const adapter = {
+	    browserDetails,
+	    commonShim,
+	    extractVersion: extractVersion,
+	    disableLog: disableLog,
+	    disableWarnings: disableWarnings
+	  };
+
+	  // Shim browser if found.
+	  switch (browserDetails.browser) {
+	    case 'chrome':
+	      if (!chromeShim || !shimPeerConnection$2 ||
+	          !options.shimChrome) {
+	        logging('Chrome shim is not included in this adapter release.');
+	        return adapter;
+	      }
+	      if (browserDetails.version === null) {
+	        logging('Chrome shim can not determine version, not shimming.');
+	        return adapter;
+	      }
+	      logging('adapter.js shimming chrome.');
+	      // Export to the adapter global object visible in the browser.
+	      adapter.browserShim = chromeShim;
+
+	      // Must be called before shimPeerConnection.
+	      shimAddIceCandidateNullOrEmpty(window, browserDetails);
+
+	      shimGetUserMedia$3(window, browserDetails);
+	      shimMediaStream(window);
+	      shimPeerConnection$2(window, browserDetails);
+	      shimOnTrack$1(window);
+	      shimAddTrackRemoveTrack(window, browserDetails);
+	      shimGetSendersWithDtmf(window);
+	      shimGetStats(window);
+	      shimSenderReceiverGetStats(window);
+	      fixNegotiationNeeded(window, browserDetails);
+
+	      shimRTCIceCandidate(window);
+	      shimConnectionState(window);
+	      shimMaxMessageSize(window, browserDetails);
+	      shimSendThrowTypeError(window);
+	      removeExtmapAllowMixed(window, browserDetails);
+	      break;
+	    case 'firefox':
+	      if (!firefoxShim || !shimPeerConnection ||
+	          !options.shimFirefox) {
+	        logging('Firefox shim is not included in this adapter release.');
+	        return adapter;
+	      }
+	      logging('adapter.js shimming firefox.');
+	      // Export to the adapter global object visible in the browser.
+	      adapter.browserShim = firefoxShim;
+
+	      // Must be called before shimPeerConnection.
+	      shimAddIceCandidateNullOrEmpty(window, browserDetails);
+
+	      shimGetUserMedia$1(window, browserDetails);
+	      shimPeerConnection(window, browserDetails);
+	      shimOnTrack(window);
+	      shimRemoveStream(window);
+	      shimSenderGetStats(window);
+	      shimReceiverGetStats(window);
+	      shimRTCDataChannel(window);
+	      shimAddTransceiver(window);
+	      shimGetParameters(window);
+	      shimCreateOffer(window);
+	      shimCreateAnswer(window);
+
+	      shimRTCIceCandidate(window);
+	      shimConnectionState(window);
+	      shimMaxMessageSize(window, browserDetails);
+	      shimSendThrowTypeError(window);
+	      break;
+	    case 'edge':
+	      if (!edgeShim || !shimPeerConnection$1 || !options.shimEdge) {
+	        logging('MS edge shim is not included in this adapter release.');
+	        return adapter;
+	      }
+	      logging('adapter.js shimming edge.');
+	      // Export to the adapter global object visible in the browser.
+	      adapter.browserShim = edgeShim;
+
+	      shimGetUserMedia$2(window);
+	      shimGetDisplayMedia$1(window);
+	      shimPeerConnection$1(window, browserDetails);
+	      shimReplaceTrack(window);
+
+	      // the edge shim implements the full RTCIceCandidate object.
+
+	      shimMaxMessageSize(window, browserDetails);
+	      shimSendThrowTypeError(window);
+	      break;
+	    case 'safari':
+	      if (!safariShim || !options.shimSafari) {
+	        logging('Safari shim is not included in this adapter release.');
+	        return adapter;
+	      }
+	      logging('adapter.js shimming safari.');
+	      // Export to the adapter global object visible in the browser.
+	      adapter.browserShim = safariShim;
+
+	      // Must be called before shimCallbackAPI.
+	      shimAddIceCandidateNullOrEmpty(window, browserDetails);
+
+	      shimRTCIceServerUrls(window);
+	      shimCreateOfferLegacy(window);
+	      shimCallbacksAPI(window);
+	      shimLocalStreamsAPI(window);
+	      shimRemoteStreamsAPI(window);
+	      shimTrackEventTransceiver(window);
+	      shimGetUserMedia(window);
+	      shimAudioContext(window);
+
+	      shimRTCIceCandidate(window);
+	      shimMaxMessageSize(window, browserDetails);
+	      shimSendThrowTypeError(window);
+	      removeExtmapAllowMixed(window, browserDetails);
+	      break;
+	    default:
+	      logging('Unsupported browser!');
+	      break;
+	  }
+
+	  return adapter;
+	}
+
+	/*
+	 *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
+	 *
+	 *  Use of this source code is governed by a BSD-style license
+	 *  that can be found in the LICENSE file in the root of the source
+	 *  tree.
+	 */
+
+	adapterFactory({window: typeof window === 'undefined' ? undefined : window});
+
+	/**
+	 * @class AudioTrackConstraints
+	 * @classDesc Constraints for creating an audio MediaStreamTrack.
+	 * @memberof Owt.Base
+	 * @constructor
+	 * @param {Owt.Base.AudioSourceInfo} source Source info of this audio track.
+	 */
+
+	class AudioTrackConstraints {
+	  // eslint-disable-next-line require-jsdoc
+	  constructor(source) {
+	    if (!Object.values(AudioSourceInfo).some(v => v === source)) {
+	      throw new TypeError('Invalid source.');
+	    }
+	    /**
+	     * @member {string} source
+	     * @memberof Owt.Base.AudioTrackConstraints
+	     * @desc Values could be "mic", "screen-cast", "file" or "mixed".
+	     * @instance
+	     */
+
+
+	    this.source = source;
+	    /**
+	     * @member {string} deviceId
+	     * @memberof Owt.Base.AudioTrackConstraints
+	     * @desc Do not provide deviceId if source is not "mic".
+	     * @instance
+	     * @see https://w3c.github.io/mediacapture-main/#def-constraint-deviceId
+	     */
+
+	    this.deviceId = undefined;
+	  }
+
+	}
+	/**
+	 * @class VideoTrackConstraints
+	 * @classDesc Constraints for creating a video MediaStreamTrack.
+	 * @memberof Owt.Base
+	 * @constructor
+	 * @param {Owt.Base.VideoSourceInfo} source Source info of this video track.
+	 */
+
+	class VideoTrackConstraints {
+	  // eslint-disable-next-line require-jsdoc
+	  constructor(source) {
+	    if (!Object.values(VideoSourceInfo).some(v => v === source)) {
+	      throw new TypeError('Invalid source.');
+	    }
+	    /**
+	     * @member {string} source
+	     * @memberof Owt.Base.VideoTrackConstraints
+	     * @desc Values could be "camera", "screen-cast", "file" or "mixed".
+	     * @instance
+	     */
+
+
+	    this.source = source;
+	    /**
+	     * @member {string} deviceId
+	     * @memberof Owt.Base.VideoTrackConstraints
+	     * @desc Do not provide deviceId if source is not "camera".
+	     * @instance
+	     * @see https://w3c.github.io/mediacapture-main/#def-constraint-deviceId
+	     */
+
+	    this.deviceId = undefined;
+	    /**
+	     * @member {Owt.Base.Resolution} resolution
+	     * @memberof Owt.Base.VideoTrackConstraints
+	     * @instance
+	     */
+
+	    this.resolution = undefined;
+	    /**
+	     * @member {number} frameRate
+	     * @memberof Owt.Base.VideoTrackConstraints
+	     * @instance
+	     */
+
+	    this.frameRate = undefined;
+	  }
+
+	}
+	/**
+	 * @class StreamConstraints
+	 * @classDesc Constraints for creating a MediaStream from screen mic and camera.
+	 * @memberof Owt.Base
+	 * @constructor
+	 * @param {?Owt.Base.AudioTrackConstraints} audioConstraints
+	 * @param {?Owt.Base.VideoTrackConstraints} videoConstraints
+	 */
+
+	class StreamConstraints {
+	  // eslint-disable-next-line require-jsdoc
+	  constructor(audioConstraints = false, videoConstraints = false) {
+	    /**
+	     * @member {Owt.Base.MediaStreamTrackDeviceConstraintsForAudio} audio
+	     * @memberof Owt.Base.MediaStreamDeviceConstraints
+	     * @instance
+	     */
+	    this.audio = audioConstraints;
+	    /**
+	     * @member {Owt.Base.MediaStreamTrackDeviceConstraintsForVideo} Video
+	     * @memberof Owt.Base.MediaStreamDeviceConstraints
+	     * @instance
+	     */
+
+	    this.video = videoConstraints;
+	  }
+
+	} // eslint-disable-next-line require-jsdoc
+
+	function isVideoConstrainsForScreenCast(constraints) {
+	  return typeof constraints.video === 'object' && constraints.video.source === VideoSourceInfo.SCREENCAST;
+	}
+	/**
+	 * @class MediaStreamFactory
+	 * @classDesc A factory to create MediaStream. You can also create MediaStream by yourself.
+	 * @memberof Owt.Base
+	 */
+
+
+	class MediaStreamFactory {
+	  /**
+	   * @function createMediaStream
+	   * @static
+	   * @desc Create a MediaStream with given constraints. If you want to create a MediaStream for screen cast, please make sure both audio and video's source are "screen-cast".
+	   * @memberof Owt.Base.MediaStreamFactory
+	   * @return {Promise<MediaStream, Error>} Return a promise that is resolved when stream is successfully created, or rejected if one of the following error happened:
+	   * - One or more parameters cannot be satisfied.
+	   * - Specified device is busy.
+	   * - Cannot obtain necessary permission or operation is canceled by user.
+	   * - Video source is screen cast, while audio source is not.
+	   * - Audio source is screen cast, while video source is disabled.
+	   * @param {Owt.Base.StreamConstraints} constraints
+	   */
+	  static createMediaStream(constraints) {
+	    if (typeof constraints !== 'object' || !constraints.audio && !constraints.video) {
+	      return Promise.reject(new TypeError('Invalid constrains'));
+	    }
+
+	    if (!isVideoConstrainsForScreenCast(constraints) && typeof constraints.audio === 'object' && constraints.audio.source === AudioSourceInfo.SCREENCAST) {
+	      return Promise.reject(new TypeError('Cannot share screen without video.'));
+	    }
+
+	    if (isVideoConstrainsForScreenCast(constraints) && !isChrome() && !isFirefox()) {
+	      return Promise.reject(new TypeError('Screen sharing only supports Chrome and Firefox.'));
+	    }
+
+	    if (isVideoConstrainsForScreenCast(constraints) && typeof constraints.audio === 'object' && constraints.audio.source !== AudioSourceInfo.SCREENCAST) {
+	      return Promise.reject(new TypeError('Cannot capture video from screen cast while capture audio from' + ' other source.'));
+	    } // Check and convert constraints.
+
+
+	    if (!constraints.audio && !constraints.video) {
+	      return Promise.reject(new TypeError('At least one of audio and video must be requested.'));
+	    }
+
+	    const mediaConstraints = Object.create({});
+
+	    if (typeof constraints.audio === 'object' && constraints.audio.source === AudioSourceInfo.MIC) {
+	      mediaConstraints.audio = Object.create({});
+
+	      if (isEdge()) {
+	        mediaConstraints.audio.deviceId = constraints.audio.deviceId;
+	      } else {
+	        mediaConstraints.audio.deviceId = {
+	          exact: constraints.audio.deviceId
+	        };
+	      }
+	    } else {
+	      if (constraints.audio.source === AudioSourceInfo.SCREENCAST) {
+	        mediaConstraints.audio = true;
+	      } else {
+	        mediaConstraints.audio = constraints.audio;
+	      }
+	    }
+
+	    if (typeof constraints.video === 'object') {
+	      mediaConstraints.video = Object.create({});
+
+	      if (typeof constraints.video.frameRate === 'number') {
+	        mediaConstraints.video.frameRate = constraints.video.frameRate;
+	      }
+
+	      if (constraints.video.resolution && constraints.video.resolution.width && constraints.video.resolution.height) {
+	        if (constraints.video.source === VideoSourceInfo.SCREENCAST) {
+	          mediaConstraints.video.width = constraints.video.resolution.width;
+	          mediaConstraints.video.height = constraints.video.resolution.height;
+	        } else {
+	          mediaConstraints.video.width = Object.create({});
+	          mediaConstraints.video.width.exact = constraints.video.resolution.width;
+	          mediaConstraints.video.height = Object.create({});
+	          mediaConstraints.video.height.exact = constraints.video.resolution.height;
+	        }
+	      }
+
+	      if (typeof constraints.video.deviceId === 'string') {
+	        mediaConstraints.video.deviceId = {
+	          exact: constraints.video.deviceId
+	        };
+	      }
+
+	      if (isFirefox() && constraints.video.source === VideoSourceInfo.SCREENCAST) {
+	        mediaConstraints.video.mediaSource = 'screen';
+	      }
+	    } else {
+	      mediaConstraints.video = constraints.video;
+	    }
+
+	    if (isVideoConstrainsForScreenCast(constraints)) {
+	      return navigator.mediaDevices.getDisplayMedia(mediaConstraints);
+	    } else {
+	      return navigator.mediaDevices.getUserMedia(mediaConstraints);
+	    }
+	  }
+
+	}
+
+	// Copyright (C) <2018> Intel Corporation
+
+	var media = /*#__PURE__*/Object.freeze({
+		__proto__: null,
+		AudioTrackConstraints: AudioTrackConstraints,
+		VideoTrackConstraints: VideoTrackConstraints,
+		StreamConstraints: StreamConstraints,
+		MediaStreamFactory: MediaStreamFactory,
+		AudioSourceInfo: AudioSourceInfo,
+		VideoSourceInfo: VideoSourceInfo,
+		TrackKind: TrackKind,
+		Resolution: Resolution
+	});
+
+	let logger;
+	let errorLogger;
+	function setLogger() {
+	  /*eslint-disable */
+	  logger = console.log;
+	  errorLogger = console.error;
+	  /*eslint-enable */
+	}
+	function log(message, ...optionalParams) {
+	  if (logger) {
+	    logger(message, ...optionalParams);
+	  }
+	}
+	function error(message, ...optionalParams) {
+	  if (errorLogger) {
+	    errorLogger(message, ...optionalParams);
+	  }
+	}
+
+	class Event$1 {
+	  constructor(type) {
+	    this.listener = {};
+	    this.type = type | '';
+	  }
+
+	  on(event, fn) {
+	    if (!this.listener[event]) {
+	      this.listener[event] = [];
+	    }
+
+	    this.listener[event].push(fn);
+	    return true;
+	  }
+
+	  off(event, fn) {
+	    if (this.listener[event]) {
+	      var index = this.listener[event].indexOf(fn);
+
+	      if (index > -1) {
+	        this.listener[event].splice(index, 1);
+	      }
+
+	      return true;
+	    }
+
+	    return false;
+	  }
+
+	  offAll() {
+	    this.listener = {};
+	  }
+
+	  dispatch(event, data) {
+	    if (this.listener[event]) {
+	      this.listener[event].map(each => {
+	        each.apply(null, [data]);
+	      });
+	      return true;
+	    }
+
+	    return false;
+	  }
+
+	}
+
+	var bind = function bind(fn, thisArg) {
+	  return function wrap() {
+	    var args = new Array(arguments.length);
+	    for (var i = 0; i < args.length; i++) {
+	      args[i] = arguments[i];
+	    }
+	    return fn.apply(thisArg, args);
+	  };
+	};
+
+	/*global toString:true*/
+
+	// utils is a library of generic helper functions non-specific to axios
+
+	var toString = Object.prototype.toString;
+
+	/**
+	 * Determine if a value is an Array
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is an Array, otherwise false
+	 */
+	function isArray(val) {
+	  return toString.call(val) === '[object Array]';
+	}
+
+	/**
+	 * Determine if a value is undefined
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if the value is undefined, otherwise false
+	 */
+	function isUndefined(val) {
+	  return typeof val === 'undefined';
+	}
+
+	/**
+	 * Determine if a value is a Buffer
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a Buffer, otherwise false
+	 */
+	function isBuffer(val) {
+	  return val !== null && !isUndefined(val) && val.constructor !== null && !isUndefined(val.constructor)
+	    && typeof val.constructor.isBuffer === 'function' && val.constructor.isBuffer(val);
+	}
+
+	/**
+	 * Determine if a value is an ArrayBuffer
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is an ArrayBuffer, otherwise false
+	 */
+	function isArrayBuffer(val) {
+	  return toString.call(val) === '[object ArrayBuffer]';
+	}
+
+	/**
+	 * Determine if a value is a FormData
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is an FormData, otherwise false
+	 */
+	function isFormData(val) {
+	  return (typeof FormData !== 'undefined') && (val instanceof FormData);
+	}
+
+	/**
+	 * Determine if a value is a view on an ArrayBuffer
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a view on an ArrayBuffer, otherwise false
+	 */
+	function isArrayBufferView(val) {
+	  var result;
+	  if ((typeof ArrayBuffer !== 'undefined') && (ArrayBuffer.isView)) {
+	    result = ArrayBuffer.isView(val);
+	  } else {
+	    result = (val) && (val.buffer) && (val.buffer instanceof ArrayBuffer);
+	  }
+	  return result;
+	}
+
+	/**
+	 * Determine if a value is a String
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a String, otherwise false
+	 */
+	function isString(val) {
+	  return typeof val === 'string';
+	}
+
+	/**
+	 * Determine if a value is a Number
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a Number, otherwise false
+	 */
+	function isNumber(val) {
+	  return typeof val === 'number';
+	}
+
+	/**
+	 * Determine if a value is an Object
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is an Object, otherwise false
+	 */
+	function isObject(val) {
+	  return val !== null && typeof val === 'object';
+	}
+
+	/**
+	 * Determine if a value is a plain Object
+	 *
+	 * @param {Object} val The value to test
+	 * @return {boolean} True if value is a plain Object, otherwise false
+	 */
+	function isPlainObject(val) {
+	  if (toString.call(val) !== '[object Object]') {
+	    return false;
+	  }
+
+	  var prototype = Object.getPrototypeOf(val);
+	  return prototype === null || prototype === Object.prototype;
+	}
+
+	/**
+	 * Determine if a value is a Date
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a Date, otherwise false
+	 */
+	function isDate(val) {
+	  return toString.call(val) === '[object Date]';
+	}
+
+	/**
+	 * Determine if a value is a File
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a File, otherwise false
+	 */
+	function isFile(val) {
+	  return toString.call(val) === '[object File]';
+	}
+
+	/**
+	 * Determine if a value is a Blob
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a Blob, otherwise false
+	 */
+	function isBlob(val) {
+	  return toString.call(val) === '[object Blob]';
+	}
+
+	/**
+	 * Determine if a value is a Function
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a Function, otherwise false
+	 */
+	function isFunction(val) {
+	  return toString.call(val) === '[object Function]';
+	}
+
+	/**
+	 * Determine if a value is a Stream
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a Stream, otherwise false
+	 */
+	function isStream(val) {
+	  return isObject(val) && isFunction(val.pipe);
+	}
+
+	/**
+	 * Determine if a value is a URLSearchParams object
+	 *
+	 * @param {Object} val The value to test
+	 * @returns {boolean} True if value is a URLSearchParams object, otherwise false
+	 */
+	function isURLSearchParams(val) {
+	  return typeof URLSearchParams !== 'undefined' && val instanceof URLSearchParams;
+	}
+
+	/**
+	 * Trim excess whitespace off the beginning and end of a string
+	 *
+	 * @param {String} str The String to trim
+	 * @returns {String} The String freed of excess whitespace
+	 */
+	function trim(str) {
+	  return str.replace(/^\s*/, '').replace(/\s*$/, '');
+	}
+
+	/**
+	 * Determine if we're running in a standard browser environment
+	 *
+	 * This allows axios to run in a web worker, and react-native.
+	 * Both environments support XMLHttpRequest, but not fully standard globals.
+	 *
+	 * web workers:
+	 *  typeof window -> undefined
+	 *  typeof document -> undefined
+	 *
+	 * react-native:
+	 *  navigator.product -> 'ReactNative'
+	 * nativescript
+	 *  navigator.product -> 'NativeScript' or 'NS'
+	 */
+	function isStandardBrowserEnv() {
+	  if (typeof navigator !== 'undefined' && (navigator.product === 'ReactNative' ||
+	                                           navigator.product === 'NativeScript' ||
+	                                           navigator.product === 'NS')) {
+	    return false;
+	  }
+	  return (
+	    typeof window !== 'undefined' &&
+	    typeof document !== 'undefined'
+	  );
+	}
+
+	/**
+	 * Iterate over an Array or an Object invoking a function for each item.
+	 *
+	 * If `obj` is an Array callback will be called passing
+	 * the value, index, and complete array for each item.
+	 *
+	 * If 'obj' is an Object callback will be called passing
+	 * the value, key, and complete object for each property.
+	 *
+	 * @param {Object|Array} obj The object to iterate
+	 * @param {Function} fn The callback to invoke for each item
+	 */
+	function forEach(obj, fn) {
+	  // Don't bother if no value provided
+	  if (obj === null || typeof obj === 'undefined') {
+	    return;
+	  }
+
+	  // Force an array if not already something iterable
+	  if (typeof obj !== 'object') {
+	    /*eslint no-param-reassign:0*/
+	    obj = [obj];
+	  }
+
+	  if (isArray(obj)) {
+	    // Iterate over array values
+	    for (var i = 0, l = obj.length; i < l; i++) {
+	      fn.call(null, obj[i], i, obj);
+	    }
+	  } else {
+	    // Iterate over object keys
+	    for (var key in obj) {
+	      if (Object.prototype.hasOwnProperty.call(obj, key)) {
+	        fn.call(null, obj[key], key, obj);
+	      }
+	    }
+	  }
+	}
+
+	/**
+	 * Accepts varargs expecting each argument to be an object, then
+	 * immutably merges the properties of each object and returns result.
+	 *
+	 * When multiple objects contain the same key the later object in
+	 * the arguments list will take precedence.
+	 *
+	 * Example:
+	 *
+	 * ```js
+	 * var result = merge({foo: 123}, {foo: 456});
+	 * console.log(result.foo); // outputs 456
+	 * ```
+	 *
+	 * @param {Object} obj1 Object to merge
+	 * @returns {Object} Result of all merge properties
+	 */
+	function merge(/* obj1, obj2, obj3, ... */) {
+	  var result = {};
+	  function assignValue(val, key) {
+	    if (isPlainObject(result[key]) && isPlainObject(val)) {
+	      result[key] = merge(result[key], val);
+	    } else if (isPlainObject(val)) {
+	      result[key] = merge({}, val);
+	    } else if (isArray(val)) {
+	      result[key] = val.slice();
+	    } else {
+	      result[key] = val;
+	    }
+	  }
+
+	  for (var i = 0, l = arguments.length; i < l; i++) {
+	    forEach(arguments[i], assignValue);
+	  }
+	  return result;
+	}
+
+	/**
+	 * Extends object a by mutably adding to it the properties of object b.
+	 *
+	 * @param {Object} a The object to be extended
+	 * @param {Object} b The object to copy properties from
+	 * @param {Object} thisArg The object to bind function to
+	 * @return {Object} The resulting value of object a
+	 */
+	function extend(a, b, thisArg) {
+	  forEach(b, function assignValue(val, key) {
+	    if (thisArg && typeof val === 'function') {
+	      a[key] = bind(val, thisArg);
+	    } else {
+	      a[key] = val;
+	    }
+	  });
+	  return a;
+	}
+
+	/**
+	 * Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
+	 *
+	 * @param {string} content with BOM
+	 * @return {string} content value without BOM
+	 */
+	function stripBOM(content) {
+	  if (content.charCodeAt(0) === 0xFEFF) {
+	    content = content.slice(1);
+	  }
+	  return content;
+	}
+
+	var utils = {
+	  isArray: isArray,
+	  isArrayBuffer: isArrayBuffer,
+	  isBuffer: isBuffer,
+	  isFormData: isFormData,
+	  isArrayBufferView: isArrayBufferView,
+	  isString: isString,
+	  isNumber: isNumber,
+	  isObject: isObject,
+	  isPlainObject: isPlainObject,
+	  isUndefined: isUndefined,
+	  isDate: isDate,
+	  isFile: isFile,
+	  isBlob: isBlob,
+	  isFunction: isFunction,
+	  isStream: isStream,
+	  isURLSearchParams: isURLSearchParams,
+	  isStandardBrowserEnv: isStandardBrowserEnv,
+	  forEach: forEach,
+	  merge: merge,
+	  extend: extend,
+	  trim: trim,
+	  stripBOM: stripBOM
+	};
+
+	function encode(val) {
+	  return encodeURIComponent(val).
+	    replace(/%3A/gi, ':').
+	    replace(/%24/g, '$').
+	    replace(/%2C/gi, ',').
+	    replace(/%20/g, '+').
+	    replace(/%5B/gi, '[').
+	    replace(/%5D/gi, ']');
+	}
+
+	/**
+	 * Build a URL by appending params to the end
+	 *
+	 * @param {string} url The base of the url (e.g., http://www.google.com)
+	 * @param {object} [params] The params to be appended
+	 * @returns {string} The formatted url
+	 */
+	var buildURL = function buildURL(url, params, paramsSerializer) {
+	  /*eslint no-param-reassign:0*/
+	  if (!params) {
+	    return url;
+	  }
+
+	  var serializedParams;
+	  if (paramsSerializer) {
+	    serializedParams = paramsSerializer(params);
+	  } else if (utils.isURLSearchParams(params)) {
+	    serializedParams = params.toString();
+	  } else {
+	    var parts = [];
+
+	    utils.forEach(params, function serialize(val, key) {
+	      if (val === null || typeof val === 'undefined') {
+	        return;
+	      }
+
+	      if (utils.isArray(val)) {
+	        key = key + '[]';
+	      } else {
+	        val = [val];
+	      }
+
+	      utils.forEach(val, function parseValue(v) {
+	        if (utils.isDate(v)) {
+	          v = v.toISOString();
+	        } else if (utils.isObject(v)) {
+	          v = JSON.stringify(v);
+	        }
+	        parts.push(encode(key) + '=' + encode(v));
+	      });
+	    });
+
+	    serializedParams = parts.join('&');
+	  }
+
+	  if (serializedParams) {
+	    var hashmarkIndex = url.indexOf('#');
+	    if (hashmarkIndex !== -1) {
+	      url = url.slice(0, hashmarkIndex);
+	    }
+
+	    url += (url.indexOf('?') === -1 ? '?' : '&') + serializedParams;
+	  }
+
+	  return url;
+	};
+
+	function InterceptorManager() {
+	  this.handlers = [];
+	}
+
+	/**
+	 * Add a new interceptor to the stack
+	 *
+	 * @param {Function} fulfilled The function to handle `then` for a `Promise`
+	 * @param {Function} rejected The function to handle `reject` for a `Promise`
+	 *
+	 * @return {Number} An ID used to remove interceptor later
+	 */
+	InterceptorManager.prototype.use = function use(fulfilled, rejected) {
+	  this.handlers.push({
+	    fulfilled: fulfilled,
+	    rejected: rejected
+	  });
+	  return this.handlers.length - 1;
+	};
+
+	/**
+	 * Remove an interceptor from the stack
+	 *
+	 * @param {Number} id The ID that was returned by `use`
+	 */
+	InterceptorManager.prototype.eject = function eject(id) {
+	  if (this.handlers[id]) {
+	    this.handlers[id] = null;
+	  }
+	};
+
+	/**
+	 * Iterate over all the registered interceptors
+	 *
+	 * This method is particularly useful for skipping over any
+	 * interceptors that may have become `null` calling `eject`.
+	 *
+	 * @param {Function} fn The function to call for each interceptor
+	 */
+	InterceptorManager.prototype.forEach = function forEach(fn) {
+	  utils.forEach(this.handlers, function forEachHandler(h) {
+	    if (h !== null) {
+	      fn(h);
+	    }
+	  });
+	};
+
+	var InterceptorManager_1 = InterceptorManager;
+
+	/**
+	 * Transform the data for a request or a response
+	 *
+	 * @param {Object|String} data The data to be transformed
+	 * @param {Array} headers The headers for the request or response
+	 * @param {Array|Function} fns A single function or Array of functions
+	 * @returns {*} The resulting transformed data
+	 */
+	var transformData = function transformData(data, headers, fns) {
+	  /*eslint no-param-reassign:0*/
+	  utils.forEach(fns, function transform(fn) {
+	    data = fn(data, headers);
+	  });
+
+	  return data;
+	};
+
+	var isCancel = function isCancel(value) {
+	  return !!(value && value.__CANCEL__);
+	};
+
+	var normalizeHeaderName = function normalizeHeaderName(headers, normalizedName) {
+	  utils.forEach(headers, function processHeader(value, name) {
+	    if (name !== normalizedName && name.toUpperCase() === normalizedName.toUpperCase()) {
+	      headers[normalizedName] = value;
+	      delete headers[name];
+	    }
+	  });
+	};
+
+	/**
+	 * Update an Error with the specified config, error code, and response.
+	 *
+	 * @param {Error} error The error to update.
+	 * @param {Object} config The config.
+	 * @param {string} [code] The error code (for example, 'ECONNABORTED').
+	 * @param {Object} [request] The request.
+	 * @param {Object} [response] The response.
+	 * @returns {Error} The error.
+	 */
+	var enhanceError = function enhanceError(error, config, code, request, response) {
+	  error.config = config;
+	  if (code) {
+	    error.code = code;
+	  }
+
+	  error.request = request;
+	  error.response = response;
+	  error.isAxiosError = true;
+
+	  error.toJSON = function toJSON() {
+	    return {
+	      // Standard
+	      message: this.message,
+	      name: this.name,
+	      // Microsoft
+	      description: this.description,
+	      number: this.number,
+	      // Mozilla
+	      fileName: this.fileName,
+	      lineNumber: this.lineNumber,
+	      columnNumber: this.columnNumber,
+	      stack: this.stack,
+	      // Axios
+	      config: this.config,
+	      code: this.code
+	    };
+	  };
+	  return error;
+	};
+
+	/**
+	 * Create an Error with the specified message, config, error code, request and response.
+	 *
+	 * @param {string} message The error message.
+	 * @param {Object} config The config.
+	 * @param {string} [code] The error code (for example, 'ECONNABORTED').
+	 * @param {Object} [request] The request.
+	 * @param {Object} [response] The response.
+	 * @returns {Error} The created error.
+	 */
+	var createError = function createError(message, config, code, request, response) {
+	  var error = new Error(message);
+	  return enhanceError(error, config, code, request, response);
+	};
+
+	/**
+	 * Resolve or reject a Promise based on response status.
+	 *
+	 * @param {Function} resolve A function that resolves the promise.
+	 * @param {Function} reject A function that rejects the promise.
+	 * @param {object} response The response.
+	 */
+	var settle = function settle(resolve, reject, response) {
+	  var validateStatus = response.config.validateStatus;
+	  if (!response.status || !validateStatus || validateStatus(response.status)) {
+	    resolve(response);
+	  } else {
+	    reject(createError(
+	      'Request failed with status code ' + response.status,
+	      response.config,
+	      null,
+	      response.request,
+	      response
+	    ));
+	  }
+	};
+
+	var cookies = (
+	  utils.isStandardBrowserEnv() ?
+
+	  // Standard browser envs support document.cookie
+	    (function standardBrowserEnv() {
+	      return {
+	        write: function write(name, value, expires, path, domain, secure) {
+	          var cookie = [];
+	          cookie.push(name + '=' + encodeURIComponent(value));
+
+	          if (utils.isNumber(expires)) {
+	            cookie.push('expires=' + new Date(expires).toGMTString());
+	          }
+
+	          if (utils.isString(path)) {
+	            cookie.push('path=' + path);
+	          }
+
+	          if (utils.isString(domain)) {
+	            cookie.push('domain=' + domain);
+	          }
+
+	          if (secure === true) {
+	            cookie.push('secure');
+	          }
+
+	          document.cookie = cookie.join('; ');
+	        },
+
+	        read: function read(name) {
+	          var match = document.cookie.match(new RegExp('(^|;\\s*)(' + name + ')=([^;]*)'));
+	          return (match ? decodeURIComponent(match[3]) : null);
+	        },
+
+	        remove: function remove(name) {
+	          this.write(name, '', Date.now() - 86400000);
+	        }
+	      };
+	    })() :
+
+	  // Non standard browser env (web workers, react-native) lack needed support.
+	    (function nonStandardBrowserEnv() {
+	      return {
+	        write: function write() {},
+	        read: function read() { return null; },
+	        remove: function remove() {}
+	      };
+	    })()
+	);
+
+	/**
+	 * Determines whether the specified URL is absolute
+	 *
+	 * @param {string} url The URL to test
+	 * @returns {boolean} True if the specified URL is absolute, otherwise false
+	 */
+	var isAbsoluteURL = function isAbsoluteURL(url) {
+	  // A URL is considered absolute if it begins with "<scheme>://" or "//" (protocol-relative URL).
+	  // RFC 3986 defines scheme name as a sequence of characters beginning with a letter and followed
+	  // by any combination of letters, digits, plus, period, or hyphen.
+	  return /^([a-z][a-z\d\+\-\.]*:)?\/\//i.test(url);
+	};
+
+	/**
+	 * Creates a new URL by combining the specified URLs
+	 *
+	 * @param {string} baseURL The base URL
+	 * @param {string} relativeURL The relative URL
+	 * @returns {string} The combined URL
+	 */
+	var combineURLs = function combineURLs(baseURL, relativeURL) {
+	  return relativeURL
+	    ? baseURL.replace(/\/+$/, '') + '/' + relativeURL.replace(/^\/+/, '')
+	    : baseURL;
+	};
+
+	/**
+	 * Creates a new URL by combining the baseURL with the requestedURL,
+	 * only when the requestedURL is not already an absolute URL.
+	 * If the requestURL is absolute, this function returns the requestedURL untouched.
+	 *
+	 * @param {string} baseURL The base URL
+	 * @param {string} requestedURL Absolute or relative URL to combine
+	 * @returns {string} The combined full path
+	 */
+	var buildFullPath = function buildFullPath(baseURL, requestedURL) {
+	  if (baseURL && !isAbsoluteURL(requestedURL)) {
+	    return combineURLs(baseURL, requestedURL);
+	  }
+	  return requestedURL;
+	};
+
+	// Headers whose duplicates are ignored by node
+	// c.f. https://nodejs.org/api/http.html#http_message_headers
+	var ignoreDuplicateOf = [
+	  'age', 'authorization', 'content-length', 'content-type', 'etag',
+	  'expires', 'from', 'host', 'if-modified-since', 'if-unmodified-since',
+	  'last-modified', 'location', 'max-forwards', 'proxy-authorization',
+	  'referer', 'retry-after', 'user-agent'
+	];
+
+	/**
+	 * Parse headers into an object
+	 *
+	 * ```
+	 * Date: Wed, 27 Aug 2014 08:58:49 GMT
+	 * Content-Type: application/json
+	 * Connection: keep-alive
+	 * Transfer-Encoding: chunked
+	 * ```
+	 *
+	 * @param {String} headers Headers needing to be parsed
+	 * @returns {Object} Headers parsed into an object
+	 */
+	var parseHeaders = function parseHeaders(headers) {
+	  var parsed = {};
+	  var key;
+	  var val;
+	  var i;
+
+	  if (!headers) { return parsed; }
+
+	  utils.forEach(headers.split('\n'), function parser(line) {
+	    i = line.indexOf(':');
+	    key = utils.trim(line.substr(0, i)).toLowerCase();
+	    val = utils.trim(line.substr(i + 1));
+
+	    if (key) {
+	      if (parsed[key] && ignoreDuplicateOf.indexOf(key) >= 0) {
+	        return;
+	      }
+	      if (key === 'set-cookie') {
+	        parsed[key] = (parsed[key] ? parsed[key] : []).concat([val]);
+	      } else {
+	        parsed[key] = parsed[key] ? parsed[key] + ', ' + val : val;
+	      }
+	    }
+	  });
+
+	  return parsed;
+	};
+
+	var isURLSameOrigin = (
+	  utils.isStandardBrowserEnv() ?
+
+	  // Standard browser envs have full support of the APIs needed to test
+	  // whether the request URL is of the same origin as current location.
+	    (function standardBrowserEnv() {
+	      var msie = /(msie|trident)/i.test(navigator.userAgent);
+	      var urlParsingNode = document.createElement('a');
+	      var originURL;
+
+	      /**
+	    * Parse a URL to discover it's components
+	    *
+	    * @param {String} url The URL to be parsed
+	    * @returns {Object}
+	    */
+	      function resolveURL(url) {
+	        var href = url;
+
+	        if (msie) {
+	        // IE needs attribute set twice to normalize properties
+	          urlParsingNode.setAttribute('href', href);
+	          href = urlParsingNode.href;
+	        }
+
+	        urlParsingNode.setAttribute('href', href);
+
+	        // urlParsingNode provides the UrlUtils interface - http://url.spec.whatwg.org/#urlutils
+	        return {
+	          href: urlParsingNode.href,
+	          protocol: urlParsingNode.protocol ? urlParsingNode.protocol.replace(/:$/, '') : '',
+	          host: urlParsingNode.host,
+	          search: urlParsingNode.search ? urlParsingNode.search.replace(/^\?/, '') : '',
+	          hash: urlParsingNode.hash ? urlParsingNode.hash.replace(/^#/, '') : '',
+	          hostname: urlParsingNode.hostname,
+	          port: urlParsingNode.port,
+	          pathname: (urlParsingNode.pathname.charAt(0) === '/') ?
+	            urlParsingNode.pathname :
+	            '/' + urlParsingNode.pathname
+	        };
+	      }
+
+	      originURL = resolveURL(window.location.href);
+
+	      /**
+	    * Determine if a URL shares the same origin as the current location
+	    *
+	    * @param {String} requestURL The URL to test
+	    * @returns {boolean} True if URL shares the same origin, otherwise false
+	    */
+	      return function isURLSameOrigin(requestURL) {
+	        var parsed = (utils.isString(requestURL)) ? resolveURL(requestURL) : requestURL;
+	        return (parsed.protocol === originURL.protocol &&
+	            parsed.host === originURL.host);
+	      };
+	    })() :
+
+	  // Non standard browser envs (web workers, react-native) lack needed support.
+	    (function nonStandardBrowserEnv() {
+	      return function isURLSameOrigin() {
+	        return true;
+	      };
+	    })()
+	);
+
+	var xhr = function xhrAdapter(config) {
+	  return new Promise(function dispatchXhrRequest(resolve, reject) {
+	    var requestData = config.data;
+	    var requestHeaders = config.headers;
+
+	    if (utils.isFormData(requestData)) {
+	      delete requestHeaders['Content-Type']; // Let the browser set it
+	    }
+
+	    var request = new XMLHttpRequest();
+
+	    // HTTP basic authentication
+	    if (config.auth) {
+	      var username = config.auth.username || '';
+	      var password = config.auth.password ? unescape(encodeURIComponent(config.auth.password)) : '';
+	      requestHeaders.Authorization = 'Basic ' + btoa(username + ':' + password);
+	    }
+
+	    var fullPath = buildFullPath(config.baseURL, config.url);
+	    request.open(config.method.toUpperCase(), buildURL(fullPath, config.params, config.paramsSerializer), true);
+
+	    // Set the request timeout in MS
+	    request.timeout = config.timeout;
+
+	    // Listen for ready state
+	    request.onreadystatechange = function handleLoad() {
+	      if (!request || request.readyState !== 4) {
+	        return;
+	      }
+
+	      // The request errored out and we didn't get a response, this will be
+	      // handled by onerror instead
+	      // With one exception: request that using file: protocol, most browsers
+	      // will return status as 0 even though it's a successful request
+	      if (request.status === 0 && !(request.responseURL && request.responseURL.indexOf('file:') === 0)) {
+	        return;
+	      }
+
+	      // Prepare the response
+	      var responseHeaders = 'getAllResponseHeaders' in request ? parseHeaders(request.getAllResponseHeaders()) : null;
+	      var responseData = !config.responseType || config.responseType === 'text' ? request.responseText : request.response;
+	      var response = {
+	        data: responseData,
+	        status: request.status,
+	        statusText: request.statusText,
+	        headers: responseHeaders,
+	        config: config,
+	        request: request
+	      };
+
+	      settle(resolve, reject, response);
+
+	      // Clean up request
+	      request = null;
+	    };
+
+	    // Handle browser request cancellation (as opposed to a manual cancellation)
+	    request.onabort = function handleAbort() {
+	      if (!request) {
+	        return;
+	      }
+
+	      reject(createError('Request aborted', config, 'ECONNABORTED', request));
+
+	      // Clean up request
+	      request = null;
+	    };
+
+	    // Handle low level network errors
+	    request.onerror = function handleError() {
+	      // Real errors are hidden from us by the browser
+	      // onerror should only fire if it's a network error
+	      reject(createError('Network Error', config, null, request));
+
+	      // Clean up request
+	      request = null;
+	    };
+
+	    // Handle timeout
+	    request.ontimeout = function handleTimeout() {
+	      var timeoutErrorMessage = 'timeout of ' + config.timeout + 'ms exceeded';
+	      if (config.timeoutErrorMessage) {
+	        timeoutErrorMessage = config.timeoutErrorMessage;
+	      }
+	      reject(createError(timeoutErrorMessage, config, 'ECONNABORTED',
+	        request));
+
+	      // Clean up request
+	      request = null;
+	    };
+
+	    // Add xsrf header
+	    // This is only done if running in a standard browser environment.
+	    // Specifically not if we're in a web worker, or react-native.
+	    if (utils.isStandardBrowserEnv()) {
+	      // Add xsrf header
+	      var xsrfValue = (config.withCredentials || isURLSameOrigin(fullPath)) && config.xsrfCookieName ?
+	        cookies.read(config.xsrfCookieName) :
+	        undefined;
+
+	      if (xsrfValue) {
+	        requestHeaders[config.xsrfHeaderName] = xsrfValue;
+	      }
+	    }
+
+	    // Add headers to the request
+	    if ('setRequestHeader' in request) {
+	      utils.forEach(requestHeaders, function setRequestHeader(val, key) {
+	        if (typeof requestData === 'undefined' && key.toLowerCase() === 'content-type') {
+	          // Remove Content-Type if data is undefined
+	          delete requestHeaders[key];
+	        } else {
+	          // Otherwise add header to the request
+	          request.setRequestHeader(key, val);
+	        }
+	      });
+	    }
+
+	    // Add withCredentials to request if needed
+	    if (!utils.isUndefined(config.withCredentials)) {
+	      request.withCredentials = !!config.withCredentials;
+	    }
+
+	    // Add responseType to request if needed
+	    if (config.responseType) {
+	      try {
+	        request.responseType = config.responseType;
+	      } catch (e) {
+	        // Expected DOMException thrown by browsers not compatible XMLHttpRequest Level 2.
+	        // But, this can be suppressed for 'json' type as it can be parsed by default 'transformResponse' function.
+	        if (config.responseType !== 'json') {
+	          throw e;
+	        }
+	      }
+	    }
+
+	    // Handle progress if needed
+	    if (typeof config.onDownloadProgress === 'function') {
+	      request.addEventListener('progress', config.onDownloadProgress);
+	    }
+
+	    // Not all browsers support upload events
+	    if (typeof config.onUploadProgress === 'function' && request.upload) {
+	      request.upload.addEventListener('progress', config.onUploadProgress);
+	    }
+
+	    if (config.cancelToken) {
+	      // Handle cancellation
+	      config.cancelToken.promise.then(function onCanceled(cancel) {
+	        if (!request) {
+	          return;
+	        }
+
+	        request.abort();
+	        reject(cancel);
+	        // Clean up request
+	        request = null;
+	      });
+	    }
+
+	    if (!requestData) {
+	      requestData = null;
+	    }
+
+	    // Send the request
+	    request.send(requestData);
+	  });
+	};
+
+	var DEFAULT_CONTENT_TYPE = {
+	  'Content-Type': 'application/x-www-form-urlencoded'
+	};
+
+	function setContentTypeIfUnset(headers, value) {
+	  if (!utils.isUndefined(headers) && utils.isUndefined(headers['Content-Type'])) {
+	    headers['Content-Type'] = value;
+	  }
+	}
+
+	function getDefaultAdapter() {
+	  var adapter;
+	  if (typeof XMLHttpRequest !== 'undefined') {
+	    // For browsers use XHR adapter
+	    adapter = xhr;
+	  } else if (typeof process !== 'undefined' && Object.prototype.toString.call(process) === '[object process]') {
+	    // For node use HTTP adapter
+	    adapter = xhr;
+	  }
+	  return adapter;
+	}
+
+	var defaults = {
+	  adapter: getDefaultAdapter(),
+
+	  transformRequest: [function transformRequest(data, headers) {
+	    normalizeHeaderName(headers, 'Accept');
+	    normalizeHeaderName(headers, 'Content-Type');
+	    if (utils.isFormData(data) ||
+	      utils.isArrayBuffer(data) ||
+	      utils.isBuffer(data) ||
+	      utils.isStream(data) ||
+	      utils.isFile(data) ||
+	      utils.isBlob(data)
+	    ) {
+	      return data;
+	    }
+	    if (utils.isArrayBufferView(data)) {
+	      return data.buffer;
+	    }
+	    if (utils.isURLSearchParams(data)) {
+	      setContentTypeIfUnset(headers, 'application/x-www-form-urlencoded;charset=utf-8');
+	      return data.toString();
+	    }
+	    if (utils.isObject(data)) {
+	      setContentTypeIfUnset(headers, 'application/json;charset=utf-8');
+	      return JSON.stringify(data);
+	    }
+	    return data;
+	  }],
+
+	  transformResponse: [function transformResponse(data) {
+	    /*eslint no-param-reassign:0*/
+	    if (typeof data === 'string') {
+	      try {
+	        data = JSON.parse(data);
+	      } catch (e) { /* Ignore */ }
+	    }
+	    return data;
+	  }],
+
+	  /**
+	   * A timeout in milliseconds to abort a request. If set to 0 (default) a
+	   * timeout is not created.
+	   */
+	  timeout: 0,
+
+	  xsrfCookieName: 'XSRF-TOKEN',
+	  xsrfHeaderName: 'X-XSRF-TOKEN',
+
+	  maxContentLength: -1,
+	  maxBodyLength: -1,
+
+	  validateStatus: function validateStatus(status) {
+	    return status >= 200 && status < 300;
+	  }
+	};
+
+	defaults.headers = {
+	  common: {
+	    'Accept': 'application/json, text/plain, */*'
+	  }
+	};
+
+	utils.forEach(['delete', 'get', 'head'], function forEachMethodNoData(method) {
+	  defaults.headers[method] = {};
+	});
+
+	utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
+	  defaults.headers[method] = utils.merge(DEFAULT_CONTENT_TYPE);
+	});
+
+	var defaults_1 = defaults;
+
+	/**
+	 * Throws a `Cancel` if cancellation has been requested.
+	 */
+	function throwIfCancellationRequested(config) {
+	  if (config.cancelToken) {
+	    config.cancelToken.throwIfRequested();
+	  }
+	}
+
+	/**
+	 * Dispatch a request to the server using the configured adapter.
+	 *
+	 * @param {object} config The config that is to be used for the request
+	 * @returns {Promise} The Promise to be fulfilled
+	 */
+	var dispatchRequest = function dispatchRequest(config) {
+	  throwIfCancellationRequested(config);
+
+	  // Ensure headers exist
+	  config.headers = config.headers || {};
+
+	  // Transform request data
+	  config.data = transformData(
+	    config.data,
+	    config.headers,
+	    config.transformRequest
+	  );
+
+	  // Flatten headers
+	  config.headers = utils.merge(
+	    config.headers.common || {},
+	    config.headers[config.method] || {},
+	    config.headers
+	  );
+
+	  utils.forEach(
+	    ['delete', 'get', 'head', 'post', 'put', 'patch', 'common'],
+	    function cleanHeaderConfig(method) {
+	      delete config.headers[method];
+	    }
+	  );
+
+	  var adapter = config.adapter || defaults_1.adapter;
+
+	  return adapter(config).then(function onAdapterResolution(response) {
+	    throwIfCancellationRequested(config);
+
+	    // Transform response data
+	    response.data = transformData(
+	      response.data,
+	      response.headers,
+	      config.transformResponse
+	    );
+
+	    return response;
+	  }, function onAdapterRejection(reason) {
+	    if (!isCancel(reason)) {
+	      throwIfCancellationRequested(config);
+
+	      // Transform response data
+	      if (reason && reason.response) {
+	        reason.response.data = transformData(
+	          reason.response.data,
+	          reason.response.headers,
+	          config.transformResponse
+	        );
+	      }
+	    }
+
+	    return Promise.reject(reason);
+	  });
+	};
+
+	/**
+	 * Config-specific merge-function which creates a new config-object
+	 * by merging two configuration objects together.
+	 *
+	 * @param {Object} config1
+	 * @param {Object} config2
+	 * @returns {Object} New object resulting from merging config2 to config1
+	 */
+	var mergeConfig = function mergeConfig(config1, config2) {
+	  // eslint-disable-next-line no-param-reassign
+	  config2 = config2 || {};
+	  var config = {};
+
+	  var valueFromConfig2Keys = ['url', 'method', 'data'];
+	  var mergeDeepPropertiesKeys = ['headers', 'auth', 'proxy', 'params'];
+	  var defaultToConfig2Keys = [
+	    'baseURL', 'transformRequest', 'transformResponse', 'paramsSerializer',
+	    'timeout', 'timeoutMessage', 'withCredentials', 'adapter', 'responseType', 'xsrfCookieName',
+	    'xsrfHeaderName', 'onUploadProgress', 'onDownloadProgress', 'decompress',
+	    'maxContentLength', 'maxBodyLength', 'maxRedirects', 'transport', 'httpAgent',
+	    'httpsAgent', 'cancelToken', 'socketPath', 'responseEncoding'
+	  ];
+	  var directMergeKeys = ['validateStatus'];
+
+	  function getMergedValue(target, source) {
+	    if (utils.isPlainObject(target) && utils.isPlainObject(source)) {
+	      return utils.merge(target, source);
+	    } else if (utils.isPlainObject(source)) {
+	      return utils.merge({}, source);
+	    } else if (utils.isArray(source)) {
+	      return source.slice();
+	    }
+	    return source;
+	  }
+
+	  function mergeDeepProperties(prop) {
+	    if (!utils.isUndefined(config2[prop])) {
+	      config[prop] = getMergedValue(config1[prop], config2[prop]);
+	    } else if (!utils.isUndefined(config1[prop])) {
+	      config[prop] = getMergedValue(undefined, config1[prop]);
+	    }
+	  }
+
+	  utils.forEach(valueFromConfig2Keys, function valueFromConfig2(prop) {
+	    if (!utils.isUndefined(config2[prop])) {
+	      config[prop] = getMergedValue(undefined, config2[prop]);
+	    }
+	  });
+
+	  utils.forEach(mergeDeepPropertiesKeys, mergeDeepProperties);
+
+	  utils.forEach(defaultToConfig2Keys, function defaultToConfig2(prop) {
+	    if (!utils.isUndefined(config2[prop])) {
+	      config[prop] = getMergedValue(undefined, config2[prop]);
+	    } else if (!utils.isUndefined(config1[prop])) {
+	      config[prop] = getMergedValue(undefined, config1[prop]);
+	    }
+	  });
+
+	  utils.forEach(directMergeKeys, function merge(prop) {
+	    if (prop in config2) {
+	      config[prop] = getMergedValue(config1[prop], config2[prop]);
+	    } else if (prop in config1) {
+	      config[prop] = getMergedValue(undefined, config1[prop]);
+	    }
+	  });
+
+	  var axiosKeys = valueFromConfig2Keys
+	    .concat(mergeDeepPropertiesKeys)
+	    .concat(defaultToConfig2Keys)
+	    .concat(directMergeKeys);
+
+	  var otherKeys = Object
+	    .keys(config1)
+	    .concat(Object.keys(config2))
+	    .filter(function filterAxiosKeys(key) {
+	      return axiosKeys.indexOf(key) === -1;
+	    });
+
+	  utils.forEach(otherKeys, mergeDeepProperties);
+
+	  return config;
+	};
+
+	/**
+	 * Create a new instance of Axios
+	 *
+	 * @param {Object} instanceConfig The default config for the instance
+	 */
+	function Axios(instanceConfig) {
+	  this.defaults = instanceConfig;
+	  this.interceptors = {
+	    request: new InterceptorManager_1(),
+	    response: new InterceptorManager_1()
+	  };
+	}
+
+	/**
+	 * Dispatch a request
+	 *
+	 * @param {Object} config The config specific for this request (merged with this.defaults)
+	 */
+	Axios.prototype.request = function request(config) {
+	  /*eslint no-param-reassign:0*/
+	  // Allow for axios('example/url'[, config]) a la fetch API
+	  if (typeof config === 'string') {
+	    config = arguments[1] || {};
+	    config.url = arguments[0];
+	  } else {
+	    config = config || {};
+	  }
+
+	  config = mergeConfig(this.defaults, config);
+
+	  // Set config.method
+	  if (config.method) {
+	    config.method = config.method.toLowerCase();
+	  } else if (this.defaults.method) {
+	    config.method = this.defaults.method.toLowerCase();
+	  } else {
+	    config.method = 'get';
+	  }
+
+	  // Hook up interceptors middleware
+	  var chain = [dispatchRequest, undefined];
+	  var promise = Promise.resolve(config);
+
+	  this.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
+	    chain.unshift(interceptor.fulfilled, interceptor.rejected);
+	  });
+
+	  this.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
+	    chain.push(interceptor.fulfilled, interceptor.rejected);
+	  });
+
+	  while (chain.length) {
+	    promise = promise.then(chain.shift(), chain.shift());
+	  }
+
+	  return promise;
+	};
+
+	Axios.prototype.getUri = function getUri(config) {
+	  config = mergeConfig(this.defaults, config);
+	  return buildURL(config.url, config.params, config.paramsSerializer).replace(/^\?/, '');
+	};
+
+	// Provide aliases for supported request methods
+	utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData(method) {
+	  /*eslint func-names:0*/
+	  Axios.prototype[method] = function(url, config) {
+	    return this.request(mergeConfig(config || {}, {
+	      method: method,
+	      url: url,
+	      data: (config || {}).data
+	    }));
+	  };
+	});
+
+	utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
+	  /*eslint func-names:0*/
+	  Axios.prototype[method] = function(url, data, config) {
+	    return this.request(mergeConfig(config || {}, {
+	      method: method,
+	      url: url,
+	      data: data
+	    }));
+	  };
+	});
+
+	var Axios_1 = Axios;
+
+	/**
+	 * A `Cancel` is an object that is thrown when an operation is canceled.
+	 *
+	 * @class
+	 * @param {string=} message The message.
+	 */
+	function Cancel(message) {
+	  this.message = message;
+	}
+
+	Cancel.prototype.toString = function toString() {
+	  return 'Cancel' + (this.message ? ': ' + this.message : '');
+	};
+
+	Cancel.prototype.__CANCEL__ = true;
+
+	var Cancel_1 = Cancel;
+
+	/**
+	 * A `CancelToken` is an object that can be used to request cancellation of an operation.
+	 *
+	 * @class
+	 * @param {Function} executor The executor function.
+	 */
+	function CancelToken(executor) {
+	  if (typeof executor !== 'function') {
+	    throw new TypeError('executor must be a function.');
+	  }
+
+	  var resolvePromise;
+	  this.promise = new Promise(function promiseExecutor(resolve) {
+	    resolvePromise = resolve;
+	  });
+
+	  var token = this;
+	  executor(function cancel(message) {
+	    if (token.reason) {
+	      // Cancellation has already been requested
+	      return;
+	    }
+
+	    token.reason = new Cancel_1(message);
+	    resolvePromise(token.reason);
+	  });
+	}
+
+	/**
+	 * Throws a `Cancel` if cancellation has been requested.
+	 */
+	CancelToken.prototype.throwIfRequested = function throwIfRequested() {
+	  if (this.reason) {
+	    throw this.reason;
+	  }
+	};
+
+	/**
+	 * Returns an object that contains a new `CancelToken` and a function that, when called,
+	 * cancels the `CancelToken`.
+	 */
+	CancelToken.source = function source() {
+	  var cancel;
+	  var token = new CancelToken(function executor(c) {
+	    cancel = c;
+	  });
+	  return {
+	    token: token,
+	    cancel: cancel
+	  };
+	};
+
+	var CancelToken_1 = CancelToken;
+
+	/**
+	 * Syntactic sugar for invoking a function and expanding an array for arguments.
+	 *
+	 * Common use case would be to use `Function.prototype.apply`.
+	 *
+	 *  ```js
+	 *  function f(x, y, z) {}
+	 *  var args = [1, 2, 3];
+	 *  f.apply(null, args);
+	 *  ```
+	 *
+	 * With `spread` this example can be re-written.
+	 *
+	 *  ```js
+	 *  spread(function(x, y, z) {})([1, 2, 3]);
+	 *  ```
+	 *
+	 * @param {Function} callback
+	 * @returns {Function}
+	 */
+	var spread = function spread(callback) {
+	  return function wrap(arr) {
+	    return callback.apply(null, arr);
+	  };
+	};
+
+	/**
+	 * Determines whether the payload is an error thrown by Axios
+	 *
+	 * @param {*} payload The value to test
+	 * @returns {boolean} True if the payload is an error thrown by Axios, otherwise false
+	 */
+	var isAxiosError = function isAxiosError(payload) {
+	  return (typeof payload === 'object') && (payload.isAxiosError === true);
+	};
+
+	/**
+	 * Create an instance of Axios
+	 *
+	 * @param {Object} defaultConfig The default config for the instance
+	 * @return {Axios} A new instance of Axios
+	 */
+	function createInstance(defaultConfig) {
+	  var context = new Axios_1(defaultConfig);
+	  var instance = bind(Axios_1.prototype.request, context);
+
+	  // Copy axios.prototype to instance
+	  utils.extend(instance, Axios_1.prototype, context);
+
+	  // Copy context to instance
+	  utils.extend(instance, context);
+
+	  return instance;
+	}
+
+	// Create the default instance to be exported
+	var axios$1 = createInstance(defaults_1);
+
+	// Expose Axios class to allow class inheritance
+	axios$1.Axios = Axios_1;
+
+	// Factory for creating new instances
+	axios$1.create = function create(instanceConfig) {
+	  return createInstance(mergeConfig(axios$1.defaults, instanceConfig));
+	};
+
+	// Expose Cancel & CancelToken
+	axios$1.Cancel = Cancel_1;
+	axios$1.CancelToken = CancelToken_1;
+	axios$1.isCancel = isCancel;
+
+	// Expose all/spread
+	axios$1.all = function all(promises) {
+	  return Promise.all(promises);
+	};
+	axios$1.spread = spread;
+
+	// Expose isAxiosError
+	axios$1.isAxiosError = isAxiosError;
+
+	var axios_1 = axios$1;
+
+	// Allow use of default import syntax in TypeScript
+	var _default = axios$1;
+	axios_1.default = _default;
+
+	var axios = axios_1;
+
+	class RTCEndpoint extends Event$1 {
+	  constructor(options) {
+	    super('RTCPusherPlayer');
+	    this.TAG = '[RTCPusherPlayer]';
+	    let defaults = {
+	      element: '',
+	      // html video element
+	      debug: false,
+	      // if output debug log
+	      zlmsdpUrl: '',
+	      simulecast: false,
+	      useCamera: true,
+	      audioEnable: true,
+	      videoEnable: true,
+	      recvOnly: false
+	    };
+	    this.options = Object.assign({}, defaults, options);
+
+	    if (this.options.debug) {
+	      setLogger();
+	    }
+
+	    this.e = {
+	      onicecandidate: this._onIceCandidate.bind(this),
+	      ontrack: this._onTrack.bind(this),
+	      onicecandidateerror: this._onIceCandidateError.bind(this)
+	    };
+	    this._remoteStream = null;
+	    this._localStream = null;
+	    this.pc = new RTCPeerConnection(null);
+	    this.pc.onicecandidate = this.e.onicecandidate;
+	    this.pc.onicecandidateerror = this.e.onicecandidateerror;
+	    this.pc.ontrack = this.e.ontrack;
+	    if (!this.options.recvOnly && (this.options.audioEnable || this.options.videoEnable)) this.start();else this.receive();
+	  }
+
+	  receive() {
+
+	    const AudioTransceiverInit = {
+	      direction: 'recvonly',
+	      sendEncodings: []
+	    };
+	    const VideoTransceiverInit = {
+	      direction: 'recvonly',
+	      sendEncodings: []
+	    };
+	    this.pc.addTransceiver('audio', AudioTransceiverInit);
+	    this.pc.addTransceiver('video', VideoTransceiverInit);
+	    this.pc.createOffer().then(desc => {
+	      log(this.TAG, 'offer:', desc.sdp);
+	      this.pc.setLocalDescription(desc).then(() => {
+	        axios({
+	          method: 'post',
+	          url: this.options.zlmsdpUrl,
+	          responseType: 'json',
+	          data: desc.sdp,
+	          headers: {
+	            'Content-Type': 'text/plain;charset=utf-8'
+	          }
+	        }).then(response => {
+	          let ret = response.data; //JSON.parse(response.data);
+
+	          if (ret.code != 0) {
+	            // mean failed for offer/anwser exchange 
+	            this.dispatch(Events$1.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED, ret);
+	            return;
+	          }
+
+	          let anwser = {};
+	          anwser.sdp = ret.sdp;
+	          anwser.type = 'answer';
+	          log(this.TAG, 'answer:', ret.sdp);
+	          this.pc.setRemoteDescription(anwser).then(() => {
+	            log(this.TAG, 'set remote sucess');
+	          }).catch(e => {
+	            error(this.TAG, e);
+	          });
+	        });
+	      });
+	    }).catch(e => {
+	      error(this.TAG, e);
+	    });
+	  }
+
+	  start() {
+	    let videoConstraints = false;
+	    let audioConstraints = false;
+
+	    if (this.options.useCamera) {
+	      if (this.options.videoEnable) videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA);
+	      if (this.options.audioEnable) audioConstraints = new AudioTrackConstraints(AudioSourceInfo.MIC);
+	    } else {
+	      if (this.options.videoEnable) {
+	        videoConstraints = new VideoTrackConstraints(VideoSourceInfo.SCREENCAST);
+	        if (this.options.audioEnable) audioConstraints = new AudioTrackConstraints(AudioSourceInfo.SCREENCAST);
+	      } else {
+	        if (this.options.audioEnable) audioConstraints = new AudioTrackConstraints(AudioSourceInfo.MIC);else {
+	          // error shared display media not only audio
+	          error(this.TAG, 'error paramter');
+	        }
+	      }
+	    }
+
+	    MediaStreamFactory.createMediaStream(new StreamConstraints(audioConstraints, videoConstraints)).then(stream => {
+	      this._localStream = stream;
+	      this.dispatch(Events$1.WEBRTC_ON_LOCAL_STREAM, stream);
+	      const AudioTransceiverInit = {
+	        direction: 'sendrecv',
+	        sendEncodings: []
+	      };
+	      const VideoTransceiverInit = {
+	        direction: 'sendrecv',
+	        sendEncodings: []
+	      };
+
+	      if (this.options.simulecast && stream.getVideoTracks().length > 0) {
+	        VideoTransceiverInit.sendEncodings = [{
+	          rid: 'q',
+	          active: true,
+	          scaleResolutionDownBy: 4.0
+	        }, {
+	          rid: 'h',
+	          active: true,
+	          scaleResolutionDownBy: 2.0
+	        }, {
+	          rid: 'f',
+	          active: true
+	        }];
+	      }
+
+	      if (stream.getAudioTracks().length > 0) {
+	        this.pc.addTransceiver(stream.getAudioTracks()[0], AudioTransceiverInit);
+	      } else {
+	        AudioTransceiverInit.direction = 'recvonly';
+	        this.pc.addTransceiver('audio', AudioTransceiverInit);
+	      }
+
+	      if (stream.getVideoTracks().length > 0) {
+	        this.pc.addTransceiver(stream.getVideoTracks()[0], VideoTransceiverInit);
+	      } else {
+	        VideoTransceiverInit.direction = 'recvonly';
+	        this.pc.addTransceiver('video', VideoTransceiverInit);
+	      }
+	      /*
+	      stream.getTracks().forEach((track,idx)=>{
+	          debug.log(this.TAG,track);
+	          this.pc.addTrack(track);
+	      });
+	      */
+
+
+	      this.pc.createOffer().then(desc => {
+	        log(this.TAG, 'offer:', desc.sdp);
+	        this.pc.setLocalDescription(desc).then(() => {
+	          axios({
+	            method: 'post',
+	            url: this.options.zlmsdpUrl,
+	            responseType: 'json',
+	            data: desc.sdp,
+	            headers: {
+	              'Content-Type': 'text/plain;charset=utf-8'
+	            }
+	          }).then(response => {
+	            let ret = response.data; //JSON.parse(response.data);
+
+	            if (ret.code != 0) {
+	              // mean failed for offer/anwser exchange 
+	              this.dispatch(Events$1.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED, ret);
+	              return;
+	            }
+
+	            let anwser = {};
+	            anwser.sdp = ret.sdp;
+	            anwser.type = 'answer';
+	            log(this.TAG, 'answer:', ret.sdp);
+	            this.pc.setRemoteDescription(anwser).then(() => {
+	              log(this.TAG, 'set remote sucess');
+	            }).catch(e => {
+	              error(this.TAG, e);
+	            });
+	          });
+	        });
+	      }).catch(e => {
+	        error(this.TAG, e);
+	      });
+	    }).catch(e => {
+	      error(this.TAG, e);
+	    }); //const offerOptions = {};
+
+	    /*
+	    if (typeof this.pc.addTransceiver === 'function') {
+	        // |direction| seems not working on Safari.
+	        this.pc.addTransceiver('audio', { direction: 'recvonly' });
+	        this.pc.addTransceiver('video', { direction: 'recvonly' });
+	    } else {
+	        offerOptions.offerToReceiveAudio = true;
+	        offerOptions.offerToReceiveVideo = true;
+	    }
+	    */
+	  }
+
+	  _onIceCandidate(event) {
+	    if (event.candidate) {
+	      log('Remote ICE candidate: \n ' + event.candidate.candidate); // Send the candidate to the remote peer
+	    }
+	  }
+
+	  _onTrack(event) {
+	    if (this.options.element && event.streams && event.streams.length > 0) {
+	      this.options.element.srcObject = event.streams[0];
+	      this._remoteStream = event.streams[0];
+	      this.dispatch(Events$1.WEBRTC_ON_REMOTE_STREAMS, event);
+	    } else {
+	      error('element pararm is failed');
+	    }
+	  }
+
+	  _onIceCandidateError(event) {
+	    this.dispatch(Events$1.WEBRTC_ICE_CANDIDATE_ERROR, event);
+	  }
+
+	  close() {
+	    if (this.pc) {
+	      this.pc.close();
+	      this.pc = null;
+	    }
+
+	    if (this.options) {
+	      this.options = null;
+	    }
+
+	    if (this._localStream) {
+	      this._localStream.getTracks().forEach((track, idx) => {
+	        track.stop();
+	      });
+	    }
+
+	    if (this._remoteStream) {
+	      this._remoteStream.getTracks().forEach((track, idx) => {
+	        track.stop();
+	      });
+	    }
+	  }
+
+	  get remoteStream() {
+	    return this._remoteStream;
+	  }
+
+	  get localStream() {
+	    return this._localStream;
+	  }
+
+	}
+
+	console.log('build date:', BUILD_DATE);
+	console.log('version:', VERSION);
+	const Events = Events$1;
+	const Media = media;
+	const Endpoint = RTCEndpoint;
+
+	exports.Endpoint = Endpoint;
+	exports.Events = Events;
+	exports.Media = Media;
+
+	Object.defineProperty(exports, '__esModule', { value: true });
+
+	return exports;
+
+}({}));
+//# sourceMappingURL=ZLMRTCClient.js.map