android-cloud-H5/static/webRtcYJ/rtcEngine.min.js

(function (global, factory) {
	typeof exports === 'object' && typeof module !== 'undefined' ? module.exports = factory() :
	typeof define === 'function' && define.amd ? define(factory) :
	(global = typeof globalThis !== 'undefined' ? globalThis : global || self, global.RtcEngine = factory());
})(this, (function () { 'use strict';

	//此文件实现将控制命令封装成协议，具体协议内容请看：
	//链接：http://note.youdao.com/noteshare?id=dabda6c613adef7a416bd2625cd770a1

	 //bcc校验码计算
	 //arry: 要计算的数组
	 //返回计算协议中校验位的校验码
	 function calBcc(arry)
	 {
		var bcc = 0;
		for(let i = 0;i < arry.length;i++)
		{
			bcc ^= arry[i];
		}
		return bcc;
	 }

	 function makeFrameExtend(sn, dataType, body)
	 {
		 var index = 0;
		 var dataLen  = body.length;
		 var frameLen = dataLen + 26;
		 var outPut = new Uint8Array(frameLen);
		 outPut[index++] = 0x68;
		 outPut[index++] = (dataLen & 0xff000000) >> 24;
		 outPut[index++] = (dataLen & 0x00ff0000) >> 16;
		 outPut[index++] = (dataLen & 0x0000ff00) >> 8;
		 outPut[index++] =  dataLen & 0x000000ff;
		 outPut[index++] = 0;//类型为client

		 //sn号赋值，string转ascii
		 for(let i = 0;i< sn.length;i++)
		 {
			 outPut[index++] = sn[i].charCodeAt();
		 }

		 outPut[index++] = dataType;//指定数据类型为json
		 //json string转ascii
		 for(let i = 0;i < body.length;i++)
		 {
			 outPut[index++] = body[i];
		 }

		 var bccBuffer = outPut.slice(1, frameLen-3 + 1);//忽略协议头和协议尾
		 outPut[index++] = calBcc(bccBuffer);
		 outPut[index++] = 0x16;
		 //var str = PrintArry(outPut);
		 //console.log("打印数组:%s", PrintArry(outPut));
		 //return PrintArry(outPut);
		 return outPut;
	 }

	 //根据报文识别屏幕方向, 0横屏，1竖屏
	 function CheckScreenDirection(data)
	 {
		if (data[0] == 0 && data[1] == 0 && data[2] == 0 &&data[3] == 1)
		{
			if (data[4] == 1 && data[5] == 1)
			{
				if (data[6] == 1)
				{
					screen = data[7];
					return screen;
				}
			}
		}
	 }

	 //查询屏幕方向
	 function GetScreenState()
	 {
		var sn = "RK3923C1201900139";
		var outPut = new Uint8Array([0x00,0x00,0x00,0x01,0x01,0x01,0x01,0x02]);
		return makeFrameExtend(sn,  5, outPut);
	 }

	//生成鉴权报文
	function VerifyCode(sn, code)
	{
		var len = code.length + 1;
		var codeBuffer = new TextEncoder("utf-8").encode(code);//获取字符串ascii码
		var buffer = new Uint8Array(len);
		buffer[0] = 0x04;

		for(let i = 0;i < codeBuffer.length;i++)
		{
			buffer[i + 1] = codeBuffer[i];
		}

		return makeFrameExtend(sn, 6, buffer);
	}

	//
	function CheckVerifyCode(data)
	{
		var dataLen = data.length - 26;
		var body = data.slice(24, 24 + dataLen);

		if(body[3] == 0x03)
		{
			return true;
		}

		return false;
	}

	//通道配置
	function ConfigChannel(sn, channelName)
	{
		var chanelBuffer = new TextEncoder("utf-8").encode(channelName);
		var outPut = [];
		outPut.push(0x07);

		for(let i = 0;i < chanelBuffer.length;i++) {
			outPut.push(chanelBuffer[i]);
		}
		return makeFrameExtend(sn, 6, outPut);
	}

	//切换清晰度
	function makeSharpness(level)
	{
		 var sn = "RK3923C1201900139";
		 var jsonObj =
		 {"type":2,"data":{"definition":level,
			"clientType": "h5",
			"sceneType": "cloudPhone"
		 }};
		 var jsonStr = JSON.stringify(jsonObj);
		 var outPut = new TextEncoder("utf-8").encode(jsonStr);
		 return makeFrameExtend(sn, 0xD, outPut);
	}

	 //I 帧请求报文生成
	 function RequestIFrame()
	 {
		 var sn = "RK3923C1201900139";
		 var outPut = new Uint8Array([0x20]);
		 return makeFrameExtend(sn, 6, outPut);
	 }

	 function setFps(frameRate) {
		let sn = "RK3923C1201900139";
		let jsonObj = { "type": 1, "data": { "frame_rate": frameRate } };
	    let jsonStr = JSON.stringify(jsonObj);
		let outPut = new TextEncoder("utf-8").encode(jsonStr);
		return makeFrameExtend(sn, 0xD, outPut);
	 }

	const Authen_ID	  	    = 0x5C;//鉴权标识
	const MultiLogin_ID      = 0x0B;//多端登录标识
	const ScreenDirection_ID = 0x05;//横竖屏状态
	const Audio_ID 		    = 0xFF;//音频标识
	const Porto_Header_ID    = 0x68;//协议头标识
	const Landscape_ID       = 0x00;//横屏标识
	const Vertica_ID         = 0X01;//竖屏标识
	const SPS_ID             = 0X07;//SPD标识
	const PPS_ID             = 0X08;//PPS标识
	const verify_Failed      = -1001;//鉴权失败
	const OPEN_SUCCESS       = 0;//拉流成功，正常显示

	function PCMPlayer(option) {
	    this.init(option);
	}

	PCMPlayer.prototype.init = function(option) {
	    var defaults = {
	        encoding: '16bitInt',
	        channels: 1,
	        sampleRate: 8000,
	        flushingTime: 1000
	    };
	    this.option = Object.assign({}, defaults, option);
	    this.samples = new Float32Array();
	    this.flush = this.flush.bind(this);
	    this.interval = setInterval(this.flush, this.option.flushingTime);
	    this.maxValue = this.getMaxValue();
	    this.typedArray = this.getTypedArray();
	    this.createContext();
	};

	PCMPlayer.prototype.getMaxValue = function () {
	    var encodings = {
	        '8bitInt': 128,
	        '16bitInt': 32768,
	        '32bitInt': 2147483648,
	        '32bitFloat': 1
	    };

	    return encodings[this.option.encoding] ? encodings[this.option.encoding] : encodings['16bitInt'];
	};

	PCMPlayer.prototype.getTypedArray = function () {
	    var typedArrays = {
	        '8bitInt': Int8Array,
	        '16bitInt': Int16Array,
	        '32bitInt': Int32Array,
	        '32bitFloat': Float32Array
	    };

	    return typedArrays[this.option.encoding] ? typedArrays[this.option.encoding] : typedArrays['16bitInt'];
	};

	PCMPlayer.prototype.createContext = function() {
	    this.audioCtx = new (window.AudioContext || window.webkitAudioContext)();
	    this.gainNode = this.audioCtx.createGain();
	    this.gainNode.gain.value = 1;
	    this.gainNode.connect(this.audioCtx.destination);
	    this.startTime = this.audioCtx.currentTime;
	};

	PCMPlayer.prototype.isTypedArray = function(data) {
	    return (data.byteLength && data.buffer && data.buffer.constructor == ArrayBuffer);
	};

	PCMPlayer.prototype.feed = function(data) {
	    if (!this.isTypedArray(data)) return;
	    data = this.getFormatedValue(data);
	    var tmp = new Float32Array(this.samples.length + data.length);
	    tmp.set(this.samples, 0);
	    tmp.set(data, this.samples.length);
	    this.samples = tmp;
	};

	PCMPlayer.prototype.getFormatedValue = function(data) {
	    var data = new this.typedArray(data.buffer),
	        float32 = new Float32Array(data.length),
	        i;

	    for (i = 0; i < data.length; i++) {
	        float32[i] = data[i] / this.maxValue;
	    }
	    return float32;
	};

	PCMPlayer.prototype.volume = function(volume) {
	    this.gainNode.gain.value = volume;
	};

	PCMPlayer.prototype.destroy = function() {
	    if (this.interval) {
	        clearInterval(this.interval);
	    }
	    this.samples = null;
	    this.audioCtx.close();
	    this.audioCtx = null;
	};

	PCMPlayer.prototype.flush = function() {
	    if (!this.samples.length) return;
	    var bufferSource = this.audioCtx.createBufferSource(),
	        length = this.samples.length / this.option.channels,
	        audioBuffer = this.audioCtx.createBuffer(this.option.channels, length, this.option.sampleRate),
	        audioData,
	        channel,
	        offset,
	        i,
	        decrement;

	    for (channel = 0; channel < this.option.channels; channel++) {
	        audioData = audioBuffer.getChannelData(channel);
	        offset = channel;
	        decrement = 50;
	        for (i = 0; i < length; i++) {
	            audioData[i] = this.samples[offset];
	            /* fadein */
	            if (i < 50) {
	                audioData[i] =  (audioData[i] * i) / 50;
	            }
	            /* fadeout*/
	            if (i >= (length - 51)) {
	                audioData[i] =  (audioData[i] * decrement--) / 50;
	            }
	            offset += this.option.channels;
	        }
	    }

	    if (this.startTime < this.audioCtx.currentTime) {
	        this.startTime = this.audioCtx.currentTime;
	    }
	    //console.log('start vs current '+this.startTime+' vs '+this.audioCtx.currentTime+' duration: '+audioBuffer.duration);
	    bufferSource.buffer = audioBuffer;
	    bufferSource.connect(this.gainNode);
	    bufferSource.start(this.startTime);
	    this.startTime += audioBuffer.duration;
	    this.samples = new Float32Array();
	};

	class AACPlayer {
	    constructor() {
	        this.pcmPlayer = new PCMPlayer({
				encoding: '16bitInt',
				channels: 2,
				sampleRate: 44100,
				flushingTime: 22,
				debug: false
			});

			this.decodeWorker = new Worker("decodeAACWorker.js");
			this.onDecodeFinished = this.onDecodeFinished.bind(this);
			this.decodeWorker.onmessage = this.onDecodeFinished;
	    }

		onDecodeFinished(event) {
			let data = event.data;
			if(data.type == "pcmData") {
				this.pcmPlayer.feed(data.data);
			}
		}

	    feed(data) {
			let info = {
				type:"aacData",
				data:data
			};
			this.decodeWorker.postMessage(info);
	    }

		stop() {
			this.decodeWorker.terminate();
			this.pcmPlayer.destroy();
		}

	}

	//import JMuxer from 'jmuxer';

	class MseConnect {

		constructor(option) {
			this.token 	        = option.token;
			this.callback       = option.callback;
			this.url            = option.url;
			this.videoId        = option.videoId;
			this.fps            = 60;

			this.wsOnMessage    = this.wsOnMessage.bind(this);
			this.wsOnClose      = this.wsOnClose.bind(this);
			this.wsOpen         = this.wsOpen.bind(this);
			this.heartBeat      = this.heartBeat.bind(this);
			this.startPlay      = this.startPlay.bind(this);
			this.wasmFinish     = false;
			this.isFeed         = true;
			this.lastRequseTime = 0;
			this.netFps			= 0;
			this.lastCalTime    = 0;
			this.videoNum		= 0;
		}

		heartBeat() {
			this.ws.send("ping");
			let interval = new Date().getTime() - this.lastRequseTime;

			if(interval >= 3000*10 && this.isFeed) {
				this.doReqesuIFrame();
				this.lastRequseTime = new Date().getTime();
			}
		}

		pause() {
			this.isFeed = false;
		}

		resume() {
			this.doReqesuIFrame();
		}

		doReqesuIFrame() {
			let buffer = RequestIFrame();
			this.ws.send(buffer);
		}

		stateCallBack(eventName, value, desc) {
			let info = {
				type:eventName,
				val: value,
				description:desc
			};
			this.callback(info);
		}

		setFps() {
			let buffer = setFps(this.fps);
			this.ws.send(buffer);
		}

		connect() {

			this.ws.onmessage   = this.wsOnMessage;
			this.ws.onopen      = this.wsOpen;
			this.ws.onclose     = this.wsOnClose;
			this.ws             = new WebSocket(this.url);
			this.ws.binaryType  = 'arraybuffer';


			this.jmuxer = new JMuxer({
				node: this.videoId,
				flushingTime:0 ,
				fps: this.fps,
				mode:'video',
				debug: false
			 });

			this.aacPlayer = new AACPlayer();
			this.videoTag = document.getElementById(this.videoId);
			let videoElement = document.getElementById(this.videoId);

	        videoElement.onplay = this.startPlay;
		}

		startPlay() {
	        this.stateCallBack("open", OPEN_SUCCESS, "拉流成功");
	    }

		parseProto (data) {
			let input = new Uint8Array(data);
			var duration, video, audio, frameType;

			if(input[0] == 0 && input[1] == 0 && input[2] == 0 && input[3] == 1) {
				video = input;
				frameType = input[4] & 0x1f;
			}

			if(input[0] == Audio_ID) {
				audio = input;
			}

			if(input[0] == Porto_Header_ID) {
				if(input[23] == MultiLogin_ID) ;

				if(input[23] == Authen_ID) {
					if(CheckVerifyCode(input)) {
						this.configChannel();
						this.setFps();
					}
					else {
						this.stateCallBack("verifyFailed", verify_Failed, "鉴权失败");
					}
				}

				if(input[23] == ScreenDirection_ID) {
					let direction = CheckScreenDirection(input.slice(24, 24 + 8));

					if(direction == Vertica_ID) {
						this.stateCallBack("screenChange", direction, "安卓卡竖屏");
					}

					if(direction == Landscape_ID) {
						this.stateCallBack("screenChange", direction, "安卓卡横屏");
					}
				}
			}

			duration = 1000/this.fps;

			return {
				audio:audio,
				video:video,
				duration:duration,
				frameType:frameType
			}
		}

		configChannel() {
			let sn = "RK3923C1201900139";
		 	this.ws.send(ConfigChannel(sn, "chaohang"));//chaohang ??
			this.ws.send(GetScreenState());
		}

		switchShapness(sharpnessLevel) {
			let buffer = makeSharpness(sharpnessLevel);
			this.ws.send(buffer);
		}

		wsOnMessage(event) {
			let data = this.parseProto(event.data);
			if(data.audio != null) {
				this.aacPlayer.feed(data.audio);
			}

			if(data.video != null) {
				if(data.frameType == SPS_ID || data.frameType == PPS_ID){
					this.isFeed = true;
				}

				if(this.isFeed)
				this.jmuxer.feed(data);
			}
		}

		wsOpen(event) {
			let sn = "RK3923C1201900139";
			let verifyBuffer = VerifyCode(sn, this.token);
			this.ws.send(verifyBuffer);
			this.heartBeatFlag = setInterval(this.heartBeat, 2000);
		}

		wsOnClose(event) {
			this.stateCallBack("closeEvent", event.code, "WS关闭事件");
		}

		disconnect() {
			clearInterval(this.heartBeatFlag);
			this.aacPlayer.stop();
			this.jmuxer.destroy();
			this.ws.close();
			this.onclose = undefined;
		}

	}

	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',
		WEBRTC_ON_CONNECTION_STATE_CHANGE: 'WEBRTC_ON_CONNECTION_STATE_CHANGE',
		WEBRTC_ON_DATA_CHANNEL_OPEN: 'WEBRTC_ON_DATA_CHANNEL_OPEN',
		WEBRTC_ON_DATA_CHANNEL_CLOSE: 'WEBRTC_ON_DATA_CHANNEL_CLOSE',
		WEBRTC_ON_DATA_CHANNEL_ERR: 'WEBRTC_ON_DATA_CHANNEL_ERR',
		WEBRTC_ON_DATA_CHANNEL_MSG: 'WEBRTC_ON_DATA_CHANNEL_MSG',
		CAPTURE_STREAM_FAILED: 'CAPTURE_STREAM_FAILED'
	};

	const VERSION$1 = '1.0.1';
	const BUILD_DATE = 'Fri Aug 26 2022 15:21:07 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 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);
			}
		}

	}

	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);
		};
	};

	// utils is a library of generic helper functions non-specific to axios

	var toString = Object.prototype.toString;

	// eslint-disable-next-line func-names
	var kindOf = (function(cache) {
		// eslint-disable-next-line func-names
		return function(thing) {
			var str = toString.call(thing);
			return cache[str] || (cache[str] = str.slice(8, -1).toLowerCase());
		};
	})(Object.create(null));

	function kindOfTest(type) {
		type = type.toLowerCase();
		return function isKindOf(thing) {
			return kindOf(thing) === type;
		};
	}

	/**
	 * 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 Array.isArray(val);
	}

	/**
	 * 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
	 *
	 * @function
	 * @param {Object} val The value to test
	 * @returns {boolean} True if value is an ArrayBuffer, otherwise false
	 */
	var isArrayBuffer = kindOfTest('ArrayBuffer');


	/**
	 * 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) && (isArrayBuffer(val.buffer));
		}
		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 (kindOf(val) !== 'object') {
			return false;
		}

		var prototype = Object.getPrototypeOf(val);
		return prototype === null || prototype === Object.prototype;
	}

	/**
	 * Determine if a value is a Date
	 *
	 * @function
	 * @param {Object} val The value to test
	 * @returns {boolean} True if value is a Date, otherwise false
	 */
	var isDate = kindOfTest('Date');

	/**
	 * Determine if a value is a File
	 *
	 * @function
	 * @param {Object} val The value to test
	 * @returns {boolean} True if value is a File, otherwise false
	 */
	var isFile = kindOfTest('File');

	/**
	 * Determine if a value is a Blob
	 *
	 * @function
	 * @param {Object} val The value to test
	 * @returns {boolean} True if value is a Blob, otherwise false
	 */
	var isBlob = kindOfTest('Blob');

	/**
	 * Determine if a value is a FileList
	 *
	 * @function
	 * @param {Object} val The value to test
	 * @returns {boolean} True if value is a File, otherwise false
	 */
	var isFileList = kindOfTest('FileList');

	/**
	 * 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 FormData
	 *
	 * @param {Object} thing The value to test
	 * @returns {boolean} True if value is an FormData, otherwise false
	 */
	function isFormData(thing) {
		var pattern = '[object FormData]';
		return thing && (
			(typeof FormData === 'function' && thing instanceof FormData) ||
			toString.call(thing) === pattern ||
			(isFunction(thing.toString) && thing.toString() === pattern)
		);
	}

	/**
	 * Determine if a value is a URLSearchParams object
	 * @function
	 * @param {Object} val The value to test
	 * @returns {boolean} True if value is a URLSearchParams object, otherwise false
	 */
	var isURLSearchParams = kindOfTest('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.trim ? str.trim() : str.replace(/^\s+|\s+$/g, '');
	}

	/**
	 * 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;
	}

	/**
	 * Inherit the prototype methods from one constructor into another
	 * @param {function} constructor
	 * @param {function} superConstructor
	 * @param {object} [props]
	 * @param {object} [descriptors]
	 */

	function inherits(constructor, superConstructor, props, descriptors) {
		constructor.prototype = Object.create(superConstructor.prototype, descriptors);
		constructor.prototype.constructor = constructor;
		props && Object.assign(constructor.prototype, props);
	}

	/**
	 * Resolve object with deep prototype chain to a flat object
	 * @param {Object} sourceObj source object
	 * @param {Object} [destObj]
	 * @param {Function} [filter]
	 * @returns {Object}
	 */

	function toFlatObject(sourceObj, destObj, filter) {
		var props;
		var i;
		var prop;
		var merged = {};

		destObj = destObj || {};

		do {
			props = Object.getOwnPropertyNames(sourceObj);
			i = props.length;
			while (i-- > 0) {
				prop = props[i];
				if (!merged[prop]) {
					destObj[prop] = sourceObj[prop];
					merged[prop] = true;
				}
			}
			sourceObj = Object.getPrototypeOf(sourceObj);
		} while (sourceObj && (!filter || filter(sourceObj, destObj)) && sourceObj !== Object.prototype);

		return destObj;
	}

	/*
	 * determines whether a string ends with the characters of a specified string
	 * @param {String} str
	 * @param {String} searchString
	 * @param {Number} [position= 0]
	 * @returns {boolean}
	 */
	function endsWith(str, searchString, position) {
		str = String(str);
		if (position === undefined || position > str.length) {
			position = str.length;
		}
		position -= searchString.length;
		var lastIndex = str.indexOf(searchString, position);
		return lastIndex !== -1 && lastIndex === position;
	}


	/**
	 * Returns new array from array like object
	 * @param {*} [thing]
	 * @returns {Array}
	 */
	function toArray(thing) {
		if (!thing) return null;
		var i = thing.length;
		if (isUndefined(i)) return null;
		var arr = new Array(i);
		while (i-- > 0) {
			arr[i] = thing[i];
		}
		return arr;
	}

	// eslint-disable-next-line func-names
	var isTypedArray = (function(TypedArray) {
		// eslint-disable-next-line func-names
		return function(thing) {
			return TypedArray && thing instanceof TypedArray;
		};
	})(typeof Uint8Array !== 'undefined' && Object.getPrototypeOf(Uint8Array));

	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,
		inherits: inherits,
		toFlatObject: toFlatObject,
		kindOf: kindOf,
		kindOfTest: kindOfTest,
		endsWith: endsWith,
		toArray: toArray,
		isTypedArray: isTypedArray,
		isFileList: isFileList
	};

	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, options) {
		this.handlers.push({
			fulfilled: fulfilled,
			rejected: rejected,
			synchronous: options ? options.synchronous : false,
			runWhen: options ? options.runWhen : null
		});
		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;

	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];
			}
		});
	};

	/**
	 * Create an Error with the specified message, config, error code, request and response.
	 *
	 * @param {string} message The error message.
	 * @param {string} [code] The error code (for example, 'ECONNABORTED').
	 * @param {Object} [config] The config.
	 * @param {Object} [request] The request.
	 * @param {Object} [response] The response.
	 * @returns {Error} The created error.
	 */
	function AxiosError(message, code, config, request, response) {
		Error.call(this);
		this.message = message;
		this.name = 'AxiosError';
		code && (this.code = code);
		config && (this.config = config);
		request && (this.request = request);
		response && (this.response = response);
	}

	utils.inherits(AxiosError, 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,
				status: this.response && this.response.status ? this.response.status : null
			};
		}
	});

	var prototype = AxiosError.prototype;
	var descriptors = {};

	[
		'ERR_BAD_OPTION_VALUE',
		'ERR_BAD_OPTION',
		'ECONNABORTED',
		'ETIMEDOUT',
		'ERR_NETWORK',
		'ERR_FR_TOO_MANY_REDIRECTS',
		'ERR_DEPRECATED',
		'ERR_BAD_RESPONSE',
		'ERR_BAD_REQUEST',
		'ERR_CANCELED'
		// eslint-disable-next-line func-names
	].forEach(function(code) {
		descriptors[code] = {
			value: code
		};
	});

	Object.defineProperties(AxiosError, descriptors);
	Object.defineProperty(prototype, 'isAxiosError', {
		value: true
	});

	// eslint-disable-next-line func-names
	AxiosError.from = function(error, code, config, request, response, customProps) {
		var axiosError = Object.create(prototype);

		utils.toFlatObject(error, axiosError, function filter(obj) {
			return obj !== Error.prototype;
		});

		AxiosError.call(axiosError, error.message, code, config, request, response);

		axiosError.name = error.name;

		customProps && Object.assign(axiosError, customProps);

		return axiosError;
	};

	var AxiosError_1 = AxiosError;

	var transitional = {
		silentJSONParsing: true,
		forcedJSONParsing: true,
		clarifyTimeoutError: false
	};

	/**
	 * Convert a data object to FormData
	 * @param {Object} obj
	 * @param {?Object} [formData]
	 * @returns {Object}
	 **/

	function toFormData(obj, formData) {
		// eslint-disable-next-line no-param-reassign
		formData = formData || new FormData();

		var stack = [];

		function convertValue(value) {
			if (value === null) return '';

			if (utils.isDate(value)) {
				return value.toISOString();
			}

			if (utils.isArrayBuffer(value) || utils.isTypedArray(value)) {
				return typeof Blob === 'function' ? new Blob([value]) : Buffer.from(value);
			}

			return value;
		}

		function build(data, parentKey) {
			if (utils.isPlainObject(data) || utils.isArray(data)) {
				if (stack.indexOf(data) !== -1) {
					throw Error('Circular reference detected in ' + parentKey);
				}

				stack.push(data);

				utils.forEach(data, function each(value, key) {
					if (utils.isUndefined(value)) return;
					var fullKey = parentKey ? parentKey + '.' + key : key;
					var arr;

					if (value && !parentKey && typeof value === 'object') {
						if (utils.endsWith(key, '{}')) {
							// eslint-disable-next-line no-param-reassign
							value = JSON.stringify(value);
						} else if (utils.endsWith(key, '[]') && (arr = utils.toArray(value))) {
							// eslint-disable-next-line func-names
							arr.forEach(function(el) {
								!utils.isUndefined(el) && formData.append(fullKey, convertValue(el));
							});
							return;
						}
					}

					build(value, fullKey);
				});

				stack.pop();
			} else {
				formData.append(parentKey, convertValue(data));
			}
		}

		build(obj);

		return formData;
	}

	var toFormData_1 = toFormData;

	/**
	 * 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(new AxiosError_1(
				'Request failed with status code ' + response.status,
				[AxiosError_1.ERR_BAD_REQUEST, AxiosError_1.ERR_BAD_RESPONSE][Math.floor(response.status /
					100) - 4],
				response.config,
				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;
			};
		})()
	);

	/**
	 * A `CanceledError` is an object that is thrown when an operation is canceled.
	 *
	 * @class
	 * @param {string=} message The message.
	 */
	function CanceledError(message) {
		// eslint-disable-next-line no-eq-null,eqeqeq
		AxiosError_1.call(this, message == null ? 'canceled' : message, AxiosError_1.ERR_CANCELED);
		this.name = 'CanceledError';
	}

	utils.inherits(CanceledError, AxiosError_1, {
		__CANCEL__: true
	});

	var CanceledError_1 = CanceledError;

	var parseProtocol = function parseProtocol(url) {
		var match = /^([-+\w]{1,25})(:?\/\/|:)/.exec(url);
		return match && match[1] || '';
	};

	var xhr = function xhrAdapter(config) {
		return new Promise(function dispatchXhrRequest(resolve, reject) {
			var requestData = config.data;
			var requestHeaders = config.headers;
			var responseType = config.responseType;
			var onCanceled;

			function done() {
				if (config.cancelToken) {
					config.cancelToken.unsubscribe(onCanceled);
				}

				if (config.signal) {
					config.signal.removeEventListener('abort', onCanceled);
				}
			}

			if (utils.isFormData(requestData) && utils.isStandardBrowserEnv()) {
				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;

			function onloadend() {
				if (!request) {
					return;
				}
				// Prepare the response
				var responseHeaders = 'getAllResponseHeaders' in request ? parseHeaders(request
					.getAllResponseHeaders()) : null;
				var responseData = !responseType || responseType === 'text' || responseType === 'json' ?
					request.responseText : request.response;
				var response = {
					data: responseData,
					status: request.status,
					statusText: request.statusText,
					headers: responseHeaders,
					config: config,
					request: request
				};

				settle(function _resolve(value) {
					resolve(value);
					done();
				}, function _reject(err) {
					reject(err);
					done();
				}, response);

				// Clean up request
				request = null;
			}

			if ('onloadend' in request) {
				// Use onloadend if available
				request.onloadend = onloadend;
			} else {
				// Listen for ready state to emulate onloadend
				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;
					}
					// readystate handler is calling before onerror or ontimeout handlers,
					// so we should call onloadend on the next 'tick'
					setTimeout(onloadend);
				};
			}

			// Handle browser request cancellation (as opposed to a manual cancellation)
			request.onabort = function handleAbort() {
				if (!request) {
					return;
				}

				reject(new AxiosError_1('Request aborted', AxiosError_1.ECONNABORTED, config, 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(new AxiosError_1('Network Error', AxiosError_1.ERR_NETWORK, config, request,
					request));

				// Clean up request
				request = null;
			};

			// Handle timeout
			request.ontimeout = function handleTimeout() {
				var timeoutErrorMessage = config.timeout ? 'timeout of ' + config.timeout + 'ms exceeded' :
					'timeout exceeded';
				var transitional$1 = config.transitional || transitional;
				if (config.timeoutErrorMessage) {
					timeoutErrorMessage = config.timeoutErrorMessage;
				}
				reject(new AxiosError_1(
					timeoutErrorMessage,
					transitional$1.clarifyTimeoutError ? AxiosError_1.ETIMEDOUT : AxiosError_1
					.ECONNABORTED,
					config,
					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 (responseType && responseType !== 'json') {
				request.responseType = config.responseType;
			}

			// 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 || config.signal) {
				// Handle cancellation
				// eslint-disable-next-line func-names
				onCanceled = function(cancel) {
					if (!request) {
						return;
					}
					reject(!cancel || (cancel && cancel.type) ? new CanceledError_1() : cancel);
					request.abort();
					request = null;
				};

				config.cancelToken && config.cancelToken.subscribe(onCanceled);
				if (config.signal) {
					config.signal.aborted ? onCanceled() : config.signal.addEventListener('abort', onCanceled);
				}
			}

			if (!requestData) {
				requestData = null;
			}

			var protocol = parseProtocol(fullPath);

			if (protocol && ['http', 'https', 'file'].indexOf(protocol) === -1) {
				reject(new AxiosError_1('Unsupported protocol ' + protocol + ':', AxiosError_1.ERR_BAD_REQUEST,
					config));
				return;
			}


			// Send the request
			request.send(requestData);
		});
	};

	// eslint-disable-next-line strict
	var _null = null;

	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;
	}

	function stringifySafely(rawValue, parser, encoder) {
		if (utils.isString(rawValue)) {
			try {
				(parser || JSON.parse)(rawValue);
				return utils.trim(rawValue);
			} catch (e) {
				if (e.name !== 'SyntaxError') {
					throw e;
				}
			}
		}

		return (encoder || JSON.stringify)(rawValue);
	}

	var defaults = {

		transitional: transitional,

		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();
			}

			var isObjectPayload = utils.isObject(data);
			var contentType = headers && headers['Content-Type'];

			var isFileList;

			if ((isFileList = utils.isFileList(data)) || (isObjectPayload && contentType ===
					'multipart/form-data')) {
				var _FormData = this.env && this.env.FormData;
				return toFormData_1(isFileList ? {
					'files[]': data
				} : data, _FormData && new _FormData());
			} else if (isObjectPayload || contentType === 'application/json') {
				setContentTypeIfUnset(headers, 'application/json');
				return stringifySafely(data);
			}

			return data;
		}],

		transformResponse: [function transformResponse(data) {
			var transitional = this.transitional || defaults.transitional;
			var silentJSONParsing = transitional && transitional.silentJSONParsing;
			var forcedJSONParsing = transitional && transitional.forcedJSONParsing;
			var strictJSONParsing = !silentJSONParsing && this.responseType === 'json';

			if (strictJSONParsing || (forcedJSONParsing && utils.isString(data) && data.length)) {
				try {
					return JSON.parse(data);
				} catch (e) {
					if (strictJSONParsing) {
						if (e.name === 'SyntaxError') {
							throw AxiosError_1.from(e, AxiosError_1.ERR_BAD_RESPONSE, this, null, this
								.response);
						}
						throw e;
					}
				}
			}

			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,

		env: {
			FormData: _null
		},

		validateStatus: function validateStatus(status) {
			return status >= 200 && status < 300;
		},

		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;

	/**
	 * 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) {
		var context = this || defaults_1;
		/*eslint no-param-reassign:0*/
		utils.forEach(fns, function transform(fn) {
			data = fn.call(context, data, headers);
		});

		return data;
	};

	var isCancel = function isCancel(value) {
		return !!(value && value.__CANCEL__);
	};

	/**
	 * Throws a `CanceledError` if cancellation has been requested.
	 */
	function throwIfCancellationRequested(config) {
		if (config.cancelToken) {
			config.cancelToken.throwIfRequested();
		}

		if (config.signal && config.signal.aborted) {
			throw new CanceledError_1();
		}
	}

	/**
	 * 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.call(
			config,
			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.call(
				config,
				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.call(
						config,
						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 = {};

		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;
		}

		// eslint-disable-next-line consistent-return
		function mergeDeepProperties(prop) {
			if (!utils.isUndefined(config2[prop])) {
				return getMergedValue(config1[prop], config2[prop]);
			} else if (!utils.isUndefined(config1[prop])) {
				return getMergedValue(undefined, config1[prop]);
			}
		}

		// eslint-disable-next-line consistent-return
		function valueFromConfig2(prop) {
			if (!utils.isUndefined(config2[prop])) {
				return getMergedValue(undefined, config2[prop]);
			}
		}

		// eslint-disable-next-line consistent-return
		function defaultToConfig2(prop) {
			if (!utils.isUndefined(config2[prop])) {
				return getMergedValue(undefined, config2[prop]);
			} else if (!utils.isUndefined(config1[prop])) {
				return getMergedValue(undefined, config1[prop]);
			}
		}

		// eslint-disable-next-line consistent-return
		function mergeDirectKeys(prop) {
			if (prop in config2) {
				return getMergedValue(config1[prop], config2[prop]);
			} else if (prop in config1) {
				return getMergedValue(undefined, config1[prop]);
			}
		}

		var mergeMap = {
			'url': valueFromConfig2,
			'method': valueFromConfig2,
			'data': valueFromConfig2,
			'baseURL': defaultToConfig2,
			'transformRequest': defaultToConfig2,
			'transformResponse': defaultToConfig2,
			'paramsSerializer': defaultToConfig2,
			'timeout': defaultToConfig2,
			'timeoutMessage': defaultToConfig2,
			'withCredentials': defaultToConfig2,
			'adapter': defaultToConfig2,
			'responseType': defaultToConfig2,
			'xsrfCookieName': defaultToConfig2,
			'xsrfHeaderName': defaultToConfig2,
			'onUploadProgress': defaultToConfig2,
			'onDownloadProgress': defaultToConfig2,
			'decompress': defaultToConfig2,
			'maxContentLength': defaultToConfig2,
			'maxBodyLength': defaultToConfig2,
			'beforeRedirect': defaultToConfig2,
			'transport': defaultToConfig2,
			'httpAgent': defaultToConfig2,
			'httpsAgent': defaultToConfig2,
			'cancelToken': defaultToConfig2,
			'socketPath': defaultToConfig2,
			'responseEncoding': defaultToConfig2,
			'validateStatus': mergeDirectKeys
		};

		utils.forEach(Object.keys(config1).concat(Object.keys(config2)), function computeConfigValue(prop) {
			var merge = mergeMap[prop] || mergeDeepProperties;
			var configValue = merge(prop);
			(utils.isUndefined(configValue) && merge !== mergeDirectKeys) || (config[prop] = configValue);
		});

		return config;
	};

	var data = {
		"version": "0.27.2"
	};

	var VERSION = data.version;


	var validators$1 = {};

	// eslint-disable-next-line func-names
	['object', 'boolean', 'number', 'function', 'string', 'symbol'].forEach(function(type, i) {
		validators$1[type] = function validator(thing) {
			return typeof thing === type || 'a' + (i < 1 ? 'n ' : ' ') + type;
		};
	});

	var deprecatedWarnings = {};

	/**
	 * Transitional option validator
	 * @param {function|boolean?} validator - set to false if the transitional option has been removed
	 * @param {string?} version - deprecated version / removed since version
	 * @param {string?} message - some message with additional info
	 * @returns {function}
	 */
	validators$1.transitional = function transitional(validator, version, message) {
		function formatMessage(opt, desc) {
			return '[Axios v' + VERSION + '] Transitional option \'' + opt + '\'' + desc + (message ? '. ' + message :
				'');
		}

		// eslint-disable-next-line func-names
		return function(value, opt, opts) {
			if (validator === false) {
				throw new AxiosError_1(
					formatMessage(opt, ' has been removed' + (version ? ' in ' + version : '')),
					AxiosError_1.ERR_DEPRECATED
				);
			}

			if (version && !deprecatedWarnings[opt]) {
				deprecatedWarnings[opt] = true;
				// eslint-disable-next-line no-console
				console.warn(
					formatMessage(
						opt,
						' has been deprecated since v' + version + ' and will be removed in the near future'
					)
				);
			}

			return validator ? validator(value, opt, opts) : true;
		};
	};

	/**
	 * Assert object's properties type
	 * @param {object} options
	 * @param {object} schema
	 * @param {boolean?} allowUnknown
	 */

	function assertOptions(options, schema, allowUnknown) {
		if (typeof options !== 'object') {
			throw new AxiosError_1('options must be an object', AxiosError_1.ERR_BAD_OPTION_VALUE);
		}
		var keys = Object.keys(options);
		var i = keys.length;
		while (i-- > 0) {
			var opt = keys[i];
			var validator = schema[opt];
			if (validator) {
				var value = options[opt];
				var result = value === undefined || validator(value, opt, options);
				if (result !== true) {
					throw new AxiosError_1('option ' + opt + ' must be ' + result, AxiosError_1.ERR_BAD_OPTION_VALUE);
				}
				continue;
			}
			if (allowUnknown !== true) {
				throw new AxiosError_1('Unknown option ' + opt, AxiosError_1.ERR_BAD_OPTION);
			}
		}
	}

	var validator = {
		assertOptions: assertOptions,
		validators: validators$1
	};

	var validators = validator.validators;
	/**
	 * 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(configOrUrl, config) {
		/*eslint no-param-reassign:0*/
		// Allow for axios('example/url'[, config]) a la fetch API
		if (typeof configOrUrl === 'string') {
			config = config || {};
			config.url = configOrUrl;
		} else {
			config = configOrUrl || {};
		}

		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';
		}

		var transitional = config.transitional;

		if (transitional !== undefined) {
			validator.assertOptions(transitional, {
				silentJSONParsing: validators.transitional(validators.boolean),
				forcedJSONParsing: validators.transitional(validators.boolean),
				clarifyTimeoutError: validators.transitional(validators.boolean)
			}, false);
		}

		// filter out skipped interceptors
		var requestInterceptorChain = [];
		var synchronousRequestInterceptors = true;
		this.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
			if (typeof interceptor.runWhen === 'function' && interceptor.runWhen(config) === false) {
				return;
			}

			synchronousRequestInterceptors = synchronousRequestInterceptors && interceptor.synchronous;

			requestInterceptorChain.unshift(interceptor.fulfilled, interceptor.rejected);
		});

		var responseInterceptorChain = [];
		this.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
			responseInterceptorChain.push(interceptor.fulfilled, interceptor.rejected);
		});

		var promise;

		if (!synchronousRequestInterceptors) {
			var chain = [dispatchRequest, undefined];

			Array.prototype.unshift.apply(chain, requestInterceptorChain);
			chain = chain.concat(responseInterceptorChain);

			promise = Promise.resolve(config);
			while (chain.length) {
				promise = promise.then(chain.shift(), chain.shift());
			}

			return promise;
		}


		var newConfig = config;
		while (requestInterceptorChain.length) {
			var onFulfilled = requestInterceptorChain.shift();
			var onRejected = requestInterceptorChain.shift();
			try {
				newConfig = onFulfilled(newConfig);
			} catch (error) {
				onRejected(error);
				break;
			}
		}

		try {
			promise = dispatchRequest(newConfig);
		} catch (error) {
			return Promise.reject(error);
		}

		while (responseInterceptorChain.length) {
			promise = promise.then(responseInterceptorChain.shift(), responseInterceptorChain.shift());
		}

		return promise;
	};

	Axios.prototype.getUri = function getUri(config) {
		config = mergeConfig(this.defaults, config);
		var fullPath = buildFullPath(config.baseURL, config.url);
		return buildURL(fullPath, config.params, config.paramsSerializer);
	};

	// 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*/

		function generateHTTPMethod(isForm) {
			return function httpMethod(url, data, config) {
				return this.request(mergeConfig(config || {}, {
					method: method,
					headers: isForm ? {
						'Content-Type': 'multipart/form-data'
					} : {},
					url: url,
					data: data
				}));
			};
		}

		Axios.prototype[method] = generateHTTPMethod();

		Axios.prototype[method + 'Form'] = generateHTTPMethod(true);
	});

	var Axios_1 = Axios;

	/**
	 * 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;

		// eslint-disable-next-line func-names
		this.promise.then(function(cancel) {
			if (!token._listeners) return;

			var i;
			var l = token._listeners.length;

			for (i = 0; i < l; i++) {
				token._listeners[i](cancel);
			}
			token._listeners = null;
		});

		// eslint-disable-next-line func-names
		this.promise.then = function(onfulfilled) {
			var _resolve;
			// eslint-disable-next-line func-names
			var promise = new Promise(function(resolve) {
				token.subscribe(resolve);
				_resolve = resolve;
			}).then(onfulfilled);

			promise.cancel = function reject() {
				token.unsubscribe(_resolve);
			};

			return promise;
		};

		executor(function cancel(message) {
			if (token.reason) {
				// Cancellation has already been requested
				return;
			}

			token.reason = new CanceledError_1(message);
			resolvePromise(token.reason);
		});
	}

	/**
	 * Throws a `CanceledError` if cancellation has been requested.
	 */
	CancelToken.prototype.throwIfRequested = function throwIfRequested() {
		if (this.reason) {
			throw this.reason;
		}
	};

	/**
	 * Subscribe to the cancel signal
	 */

	CancelToken.prototype.subscribe = function subscribe(listener) {
		if (this.reason) {
			listener(this.reason);
			return;
		}

		if (this._listeners) {
			this._listeners.push(listener);
		} else {
			this._listeners = [listener];
		}
	};

	/**
	 * Unsubscribe from the cancel signal
	 */

	CancelToken.prototype.unsubscribe = function unsubscribe(listener) {
		if (!this._listeners) {
			return;
		}
		var index = this._listeners.indexOf(listener);
		if (index !== -1) {
			this._listeners.splice(index, 1);
		}
	};

	/**
	 * 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 utils.isObject(payload) && (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);

		// Factory for creating new instances
		instance.create = function create(instanceConfig) {
			return createInstance(mergeConfig(defaultConfig, instanceConfig));
		};

		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;

	// Expose Cancel & CancelToken
	axios$1.CanceledError = CanceledError_1;
	axios$1.CancelToken = CancelToken_1;
	axios$1.isCancel = isCancel;
	axios$1.VERSION = data.version;
	axios$1.toFormData = toFormData_1;

	// Expose AxiosError class
	axios$1.AxiosError = AxiosError_1;

	// alias for CanceledError for backward compatibility
	axios$1.Cancel = axios$1.CanceledError;

	// 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: '',
				simulcast: false,
				useCamera: true,
				audioEnable: true,
				videoEnable: true,
				recvOnly: false,
				resolution: {
					w: 0,
					h: 0
				},
				usedatachannel: 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),
				onconnectionstatechange: this._onconnectionstatechange.bind(this),
				ondatachannelopen: this._onDataChannelOpen.bind(this),
				ondatachannelmsg: this._onDataChannelMsg.bind(this),
				ondatachannelerr: this._onDataChannelErr.bind(this),
				ondatachannelclose: this._onDataChannelClose.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;
			this.pc.onconnectionstatechange = this.e.onconnectionstatechange;
			this.datachannel = null;

			if (this.options.usedatachannel) {
				this.datachannel = this.pc.createDataChannel('chat');
				this.datachannel.onclose = this.e.ondatachannelclose;
				this.datachannel.onerror = this.e.ondatachannelerr;
				this.datachannel.onmessage = this.e.ondatachannelmsg;
				this.datachannel.onopen = this.e.ondatachannelopen;
			}

			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: []
			};

			if (this.options.videoEnable) {
				this.pc.addTransceiver('video', VideoTransceiverInit);
			}

			if (this.options.audioEnable) {
				this.pc.addTransceiver('audio', AudioTransceiverInit);
			}

			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 = {};
						var re = this.replaceCandidate(ret.sdp);
						anwser.sdp = re;
						anwser.type = 'answer';
						log(this.TAG, 'answer:', ret.sdp);
						this.pc.setRemoteDescription(anwser).then(() => {
							this.options.successCallback()
							log(this.TAG, 'set remote sucess');
						}).catch(e => {
							error(this.TAG, e);
						});
					});
				});
			}).catch(e => {
				error(this.TAG, e);
			});
		}

		splitSections(blob) {
			var parts = blob.split('\nm=');
			return parts.map(function(part, index) {
				return (index > 0 ? 'm=' + part : part).trim() + '\r\n';
			});
		}

		splitLines(blob) {
			return blob.trim().split('\n').map(function(line) {
				return line.trim();
			});
		}

		matchPrefixExt(blob, prefix) {
			return this.splitLines(blob).filter(function(line) {
				return line.indexOf(prefix) === 0;
			});
		}
		replaceCandidate(sdp) {
			var sections = this.splitSections(sdp);
			var cands;
			sections.forEach(e => {
				// console.log('==========eee',e)
				cands = this.matchPrefixExt(e, 'a=candidate:');
				// console.log(cands[0]);
			});
			// console.log("=======ip---------", window.cloudgame_sdk.extraData.remainingTimeData.data.extranetIp, window.cloudgame_sdk.extraData.remainingTimeData.data.extranetPort);
			let aaa =
				`a=candidate:udpcandidate 1 udp 120 ${extranetIp} ${extranetPort} typ host`;

      var data = '';
			// const deviceInline = CLOUD_GAME_SDK.getQueryVariable("deviceInline")
			if (window.location.protocol === 'http:') {
				data = sdp;
			} else {
				// data = sdp.replaceAll(cands[0], aaa);
				// data = sdp.replace(/cands[0]/g, aaa);
				data = sdp.replace(new RegExp(cands[0], 'g'), aaa);
			}


			// const data = sdp
			return data
			// console.log(sections);
		}

		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');
					}
				}
			}

			if (this.options.resolution.w != 0 && this.options.resolution.h != 0 && typeof videoConstraints ==
				'object') {
				videoConstraints.resolution = new Resolution(this.options.resolution.w, this.options.resolution.h);
			}

			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.simulcast && stream.getVideoTracks().length > 0) {
						VideoTransceiverInit.sendEncodings = [{
							rid: 'h',
							active: true,
							maxBitrate: 1000000
						}, {
							rid: 'm',
							active: true,
							maxBitrate: 500000,
							scaleResolutionDownBy: 2
						}, {
							rid: 'l',
							active: true,
							maxBitrate: 200000,
							scaleResolutionDownBy: 4
						}];
					}

					if (this.options.audioEnable) {
						if (stream.getAudioTracks().length > 0) {
							this.pc.addTransceiver(stream.getAudioTracks()[0], AudioTransceiverInit);
						} else {
							AudioTransceiverInit.direction = 'recvonly';
							this.pc.addTransceiver('audio', AudioTransceiverInit);
						}
					}

					if (this.options.videoEnable) {
						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 => {
				this.dispatch(Events$1.CAPTURE_STREAM_FAILED); //debug.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);
		}

		_onconnectionstatechange(event) {
			this.dispatch(Events$1.WEBRTC_ON_CONNECTION_STATE_CHANGE, this.pc.connectionState);
		}

		_onDataChannelOpen(event) {
			log(this.TAG, 'ondatachannel open:', event);
			this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_OPEN, event);
		}

		_onDataChannelMsg(event) {
			log(this.TAG, 'ondatachannel msg:', event);
			this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_MSG, event);
		}

		_onDataChannelErr(event) {
			log(this.TAG, 'ondatachannel err:', event);
			this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_ERR, event);
		}

		_onDataChannelClose(event) {
			log(this.TAG, 'ondatachannel close:', event);
			this.dispatch(Events$1.WEBRTC_ON_DATA_CHANNEL_CLOSE, event);
		}

		sendMsg(data) {
			if (this.datachannel != null) {
				this.datachannel.send(data);
			} else {
				error(this.TAG, 'data channel is null');
			}
		}

		closeDataChannel() {
			if (this.datachannel) {
				this.datachannel.close();
				this.datachannel = null;
			}
		}

		close() {
			this.closeDataChannel();

			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$1);
	const Events = Events$1;
	const Endpoint = RTCEndpoint;

	//连接webrtc

	class ZLMConnect {

	    constructor(option) {
	        this.token 	        = option.token;
			this.callback       = option.callback;
	        this.url            = option.url;
	        this.videoId        = option.videoId;
	        this.rtcUrl         = option.rtcUrl;
			this.successCallback = option.successCallback;
	    }

	    stateCallBack(eventName, value, desc) {
			let info = {
				type:eventName,
				val: value,
				description:desc
			};
			this.callback(info);
		}

	    connect() {
	        this.wsOnMessage    = this.wsOnMessage.bind(this);
			this.wsOnClose      = this.wsOnClose.bind(this);
			this.wsOpen         = this.wsOpen.bind(this);
	        this.heartBeat      = this.heartBeat.bind(this);
	        this.startPlay      = this.startPlay.bind(this);

	        this.ws             = new WebSocket(this.url);
			this.ws.binaryType  = 'arraybuffer';
			this.ws.onmessage   = this.wsOnMessage;
			this.ws.onopen      = this.wsOpen;
			this.ws.onclose     = this.wsOnClose;

	        //this.connectRtc();
	    }

	    pause() {
	        let videoElement = document.getElementById(this.videoId);
	        videoElement.pause();
	        console.log("webrtc暂停");
	    }

	    resume() {
	        let videoElement = document.getElementById(this.videoId);
	        videoElement.play();
	        console.log("webrtc继续播放");
	    }

	    connectRtc() {
	        this.player = new Endpoint(
	        {
	            element: document.getElementById(this.videoId),// video 标签
	            debug: true,// 是否打印日志
	            zlmsdpUrl:this.rtcUrl,//流地址
	            simulcast:false,
	            useCamera:false,
	            audioEnable:true,
	            videoEnable:true,
	            recvOnly:true,
	            usedatachannel:false,
				successCallback: this.successCallback
	        });

	        this.player.on(Events.WEBRTC_ON_REMOTE_STREAMS,function(e)
	        {//获取到了远端流，可以播放
	            console.log('播放成功',e.streams);
	        });

	        this.player.on(Events.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED,function(e)
	        {// offer anwser 交换失败
	            console.log('offer anwser 交换失败',e);
	            stop();
	        });

	        this.player.on(Events.WEBRTC_ON_CONNECTION_STATE_CHANGE,function(state)
	        {// RTC 状态变化 ,详情参考 https://developer.mozilla.org/en-US/docs/Web/API/RTCPeerConnection/connectionState
	            console.log('当前状态==>',state);
	        });

	        this.player.on(Events.WEBRTC_ON_DATA_CHANNEL_OPEN,function(event)
	        {
	            console.log('rtc datachannel 打开 :',event);
	        });

	        this.player.on(Events.WEBRTC_ON_DATA_CHANNEL_MSG,function(event)
	        {
	            console.log('rtc datachannel 消息 :',event.data);
	            document.getElementById('msgrecv').value = event.data;
	        });

	        this.player.on(Events.WEBRTC_ON_DATA_CHANNEL_ERR,function(event)
	        {
	            console.log('rtc datachannel 错误 :',event);
	        });

	        this.player.on(Events.WEBRTC_ON_DATA_CHANNEL_CLOSE,function(event)
	        {
	            console.log('rtc datachannel 关闭 :',event);
	        });

	        let videoElement = document.getElementById(this.videoId);
	        videoElement.onplay = this.startPlay;
		}

	    startPlay() {
	        this.stateCallBack("open", OPEN_SUCCESS, "拉流成功");
	    }

	    wsOnMessage(event) {
			this.parseProto(event.data);
		}

	    switchShapness(level) {
	        this.ws.send(makeSharpness(level));
	    }

	    parseProto (data) {
			let input = new Uint8Array(data);

			if(input[0] == Porto_Header_ID) {
				if(input[23] == MultiLogin_ID) ;

				if(input[23] == Authen_ID) {
					if(CheckVerifyCode(input)) {
	                    this.connectRtc();
					}
					else {
						console.log("鉴权失败:" + input);
						this.stateCallBack("verifyFailed", verify_Failed, "鉴权失败");
					}
				}

				if(input[23] == ScreenDirection_ID) {
					let direction = CheckScreenDirection(input.slice(24, 24 + 8));

					if(direction == Vertica_ID) {
						this.stateCallBack("screenChange", direction, "安卓卡竖屏");
					}

					if(direction == Landscape_ID) {
						this.stateCallBack("screenChange", direction, "安卓卡横屏");
					}
				}
			}
		}

	    heartBeat() {
			this.ws.send("ping");
		}

		wsOpen(event) {
			let sn = "RK3923C1201900139";
			let verifyBuffer = VerifyCode(sn, this.token);
			this.ws.send(verifyBuffer);
			this.heartBeatFlag = setInterval(this.heartBeat, 2000);
		}

		wsOnClose(event) {
			this.stateCallBack("closeEvent", event.code, "WS关闭事件");
		}

	    disconnect() {
	        if(this.player) {
	            this.player.close();
	            this.player = null;
	        }

	        clearInterval(this.heartBeatFlag);
	        this.ws.close();
	        let videoElement = document.getElementById(this.videoId);
	        videoElement.srcObject = null;
	        videoElement.load();
	    }

	}

	class RtcEngine {
		constructor(options) {
			this.callback = options.callback;
			this.url = options.url;
			this.token = options.token;
			this.videoId = options.videoId;
			this.rtcUrl = options.rtcUrl;
			this.mode = options.mode;
			this.debug = options.debug;
			this.successCallback = options.successCallback;
		}

		checkSupportLevel() {
			let isWebrtcSupported = DetectRTC.isWebRTCSupported;
			let isMseSupported = !!window.MediaSource;
			let isWasmSupported = false;

			if(isWebrtcSupported) {
				console.log("支持webrtc--yes");
			}

			if(isMseSupported) {
				console.log("支持MSE--yes");
			}

			return {
				webrtcSupported:isWebrtcSupported,
				mseSupported:isMseSupported,
				webCodecSupported:isMseSupported,
				wasmSupported:isWasmSupported
			}

		}

		getMode() {
			return this.mode;
		}

		switchShapness(level) {
			if(this.connector != undefined) {
				this.connector.switchShapness(level);
			}
		}

		//优先级webrtc > webcodec > mse > wasm
		checkAndConnect() {
			let supportLevel = this.checkSupportLevel();

			if(supportLevel.webrtcSupported) {
				this.connector = new ZLMConnect(this.rtcOption);
				this.mode = "webrtc";
			}
			else
			if(supportLevel.mseSupported) {
				this.connector = new MseConnect(this.rtcOption);
				this.mode = "mse";
			}
			else
			if(supportLevel.webCodecSupported) {
				this.mode = "webcodec";
				console.log("暂时不支持webcodec");
			}
			else
			if(supportLevel.wasmSupported) {
				this.mode = "wasm";
				console.log("暂时不支持wasm");
			}

			if(this.connector != undefined)
				this.connector.connect();
		}

		connect() {
			this.rtcOption = {
				url:this.url,
				token:this.token,
				videoId:this.videoId,
				callback:this.callback,
				rtcUrl:this.rtcUrl,
				debug:this.debug,
				successCallback: this.successCallback

			};

			if(this.mode != undefined) {
				switch(this.mode) {
					case "mse":this.connector = new MseConnect(this.rtcOption);break;
					case "webrtc":this.connector = new ZLMConnect(this.rtcOption);break;
					default:console.log("暂时不支持的流媒体协议:" + this.mode);break;
				}

				if(this.connector != undefined)
					this.connector.connect();
			}
			else {
				this.checkAndConnect();
			}

		}

		pause() {
			if(this.connector.pause != undefined) {
				this.connector.pause();
			}
		}

		resume() {
			if(this.connector.resume != undefined) {
				this.connector.resume();
			}
		}

		disconnect() {
			this.connector.disconnect();
		}
	}

	return RtcEngine;

}));