File: source/stream-sdp.js

                      /**
                       * Function that modifies the session description to configure settings for OPUS audio codec.
                       * @method _setSDPCodecParams
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._setSDPCodecParams = function(targetMid, sessionDescription) {
                        var self = this;
                      
                        var parseFn = function (type, codecName, samplingRate, settings) {
                          var mLine = sessionDescription.sdp.match(new RegExp('m=' + type + '\ .*\r\n', 'gi'));
                          // Find the m= line
                          if (Array.isArray(mLine) && mLine.length > 0) {
                            var codecsList = sessionDescription.sdp.match(new RegExp('a=rtpmap:.*\ ' + codecName + '\/' +
                              (samplingRate ? samplingRate + (type === 'audio' ? '[\/]*.*' : '.*') : '.*') + '\r\n', 'gi'));
                            // Get the list of codecs related to it
                            if (Array.isArray(codecsList) && codecsList.length > 0) {
                              for (var i = 0; i < codecsList.length; i++) {
                                var payload = (codecsList[i].split('a=rtpmap:')[1] || '').split(' ')[0];
                                if (!payload) {
                                  continue;
                                }
                                var fmtpLine = sessionDescription.sdp.match(new RegExp('a=fmtp:' + payload + '\ .*\r\n', 'gi'));
                                var updatedFmtpLine = 'a=fmtp:' + payload + ' ';
                                var addedKeys = [];
                                // Check if a=fmtp: line exists
                                if (Array.isArray(fmtpLine) && fmtpLine.length > 0) {
                                  var fmtpParts = (fmtpLine[0].split('a=fmtp:' + payload + ' ')[1] || '').replace(
                                    / /g, '').replace(/\r\n/g, '').split(';');
                                  for (var j = 0; j < fmtpParts.length; j++) {
                                    if (!fmtpParts[j]) {
                                      continue;
                                    }
                                    var keyAndValue = fmtpParts[j].split('=');
                                    if (settings.hasOwnProperty(keyAndValue[0])) {
                                      // Dont append parameter key+value if boolean and false
                                      updatedFmtpLine += typeof settings[keyAndValue[0]] === 'boolean' ? (settings[keyAndValue[0]] ?
                                        keyAndValue[0] + '=1;' : '') : keyAndValue[0] + '=' + settings[keyAndValue[0]] + ';';
                                    } else {
                                      updatedFmtpLine += fmtpParts[j] + ';';
                                    }
                                    addedKeys.push(keyAndValue[0]);
                                  }
                                  sessionDescription.sdp = sessionDescription.sdp.replace(fmtpLine[0], '');
                                }
                                for (var key in settings) {
                                  if (settings.hasOwnProperty(key) && addedKeys.indexOf(key) === -1) {
                                    // Dont append parameter key+value if boolean and false
                                    updatedFmtpLine += typeof settings[key] === 'boolean' ? (settings[key] ? key + '=1;' : '') :
                                      key + '=' + settings[key] + ';';
                                    addedKeys.push(key);
                                  }
                                }
                                if (updatedFmtpLine !== 'a=fmtp:' + payload + ' ') {
                                  sessionDescription.sdp = sessionDescription.sdp.replace(codecsList[i], codecsList[i] + updatedFmtpLine + '\r\n');
                                }
                              }
                            }
                          }
                        };
                      
                        // Set audio codecs -> OPUS
                        // RFC: https://tools.ietf.org/html/draft-ietf-payload-rtp-opus-11
                        parseFn('audio', self.AUDIO_CODEC.OPUS, 48000, (function () {
                          var opusOptions = {};
                          var audioSettings = self.getPeerInfo().settings.audio;
                          audioSettings = audioSettings && typeof audioSettings === 'object' ? audioSettings : {};
                          if (typeof self._codecParams.audio.opus.stereo === 'boolean') {
                            opusOptions.stereo = self._codecParams.audio.opus.stereo;
                          } else if (typeof audioSettings.stereo === 'boolean') {
                            opusOptions.stereo = audioSettings.stereo;
                          }
                          if (typeof self._codecParams.audio.opus.usedtx === 'boolean') {
                            opusOptions.usedtx = self._codecParams.audio.opus.usedtx;
                          } else if (typeof audioSettings.usedtx === 'boolean') {
                            opusOptions.usedtx = audioSettings.usedtx;
                          }
                          if (typeof self._codecParams.audio.opus.useinbandfec === 'boolean') {
                            opusOptions.useinbandfec = self._codecParams.audio.opus.useinbandfec;
                          } else if (typeof audioSettings.useinbandfec === 'boolean') {
                            opusOptions.useinbandfec = audioSettings.useinbandfec;
                          }
                          if (typeof self._codecParams.audio.opus.maxplaybackrate === 'number') {
                            opusOptions.maxplaybackrate = self._codecParams.audio.opus.maxplaybackrate;
                          } else if (typeof audioSettings.maxplaybackrate === 'number') {
                            opusOptions.maxplaybackrate = audioSettings.maxplaybackrate;
                          }
                          if (typeof self._codecParams.audio.opus.minptime === 'number') {
                            opusOptions.minptime = self._codecParams.audio.opus.minptime;
                          } else if (typeof audioSettings.minptime === 'number') {
                            opusOptions.minptime = audioSettings.minptime;
                          }
                          // Possible future params: sprop-maxcapturerate, maxaveragebitrate, sprop-stereo, cbr
                          // NOT recommended: maxptime, ptime, rate, minptime
                          return opusOptions;
                        })());
                      
                        // RFC: https://tools.ietf.org/html/rfc4733
                        // Future: Set telephone-event: 100 0-15,66,70
                      
                        // RFC: https://tools.ietf.org/html/draft-ietf-payload-vp8-17
                        // Set video codecs -> VP8
                        parseFn('video', self.VIDEO_CODEC.VP8, null, (function () {
                          var vp8Options = {};
                          // NOT recommended: max-fr, max-fs (all are codec decoder capabilities)
                          if (typeof self._codecParams.video.vp8.maxFr === 'number') {
                            vp8Options['max-fr'] = self._codecParams.video.vp8.maxFr;
                          }
                          if (typeof self._codecParams.video.vp8.maxFs === 'number') {
                            vp8Options['max-fs'] = self._codecParams.video.vp8.maxFs;
                          }
                          return vp8Options;
                        })());
                      
                        // RFC: https://tools.ietf.org/html/draft-ietf-payload-vp9-02
                        // Set video codecs -> VP9
                        parseFn('video', self.VIDEO_CODEC.VP9, null, (function () {
                          var vp9Options = {};
                          // NOT recommended: max-fr, max-fs (all are codec decoder capabilities)
                          if (typeof self._codecParams.video.vp9.maxFr === 'number') {
                            vp9Options['max-fr'] = self._codecParams.video.vp9.maxFr;
                          }
                          if (typeof self._codecParams.video.vp9.maxFs === 'number') {
                            vp9Options['max-fs'] = self._codecParams.video.vp9.maxFs;
                          }
                          return vp9Options;
                        })());
                      
                        // RFC: https://tools.ietf.org/html/rfc6184
                        // Set the video codecs -> H264
                        parseFn('video', self.VIDEO_CODEC.H264, null, (function () {
                          var h264Options = {};
                          if (typeof self._codecParams.video.h264.levelAsymmetryAllowed === 'string') {
                            h264Options['profile-level-id'] = self._codecParams.video.h264.profileLevelId;
                          }
                          if (typeof self._codecParams.video.h264.levelAsymmetryAllowed === 'boolean') {
                            h264Options['level-asymmetry-allowed'] = self._codecParams.video.h264.levelAsymmetryAllowed;
                          }
                          if (typeof self._codecParams.video.h264.packetizationMode === 'boolean') {
                            h264Options['packetization-mode'] = self._codecParams.video.h264.packetizationMode;
                          }
                          // Possible future params (remove if they are decoder/encoder capabilities or info):
                          //   max-recv-level, max-mbps, max-smbps, max-fs, max-cpb, max-dpb, max-br,
                          //   max-mbps, max-smbps, max-fs, max-cpb, max-dpb, max-br, redundant-pic-cap, sprop-parameter-sets,
                          //   sprop-level-parameter-sets, use-level-src-parameter-sets, in-band-parameter-sets,
                          //   sprop-interleaving-depth, sprop-deint-buf-req, deint-buf-cap, sprop-init-buf-time,
                          //   sprop-max-don-diff, max-rcmd-nalu-size, sar-understood, sar-supported
                          //   NOT recommended: profile-level-id (WebRTC uses "42e00a" for the moment)
                          //   https://bugs.chromium.org/p/chromium/issues/detail?id=645599
                          return h264Options;
                        })());
                      
                        return sessionDescription.sdp;
                      };
                      
                      /**
                       * Function that modifies the session description to limit the maximum sending bandwidth.
                       * Setting this may not necessarily work in Firefox.
                       * @method _setSDPBitrate
                       * @private
                       * @for Skylink
                       * @since 0.5.10
                       */
                      Skylink.prototype._setSDPBitrate = function(targetMid, sessionDescription) {
                        var sdpLines = sessionDescription.sdp.split('\r\n');
                        var parseFn = function (type, bw) {
                          var mLineType = type;
                          var mLineIndex = -1;
                          var cLineIndex = -1;
                      
                          if (type === 'data') {
                            mLineType = 'application';
                          }
                      
                          for (var i = 0; i < sdpLines.length; i++) {
                            if (sdpLines[i].indexOf('m=' + mLineType) === 0) {
                              mLineIndex = i;
                            } else if (mLineIndex > 0) {
                              if (sdpLines[i].indexOf('m=') === 0) {
                                break;
                              }
                      
                              if (sdpLines[i].indexOf('c=') === 0) {
                                cLineIndex = i;
                              // Remove previous b:AS settings
                              } else if (sdpLines[i].indexOf('b=AS:') === 0 || sdpLines[i].indexOf('b:TIAS:') === 0) {
                                sdpLines.splice(i, 1);
                                i--;
                              }
                            }
                          }
                      
                          if (!(typeof bw === 'number' && bw > 0)) {
                            log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Not limiting "' + type + '" bandwidth']);
                            return;
                          }
                      
                          if (cLineIndex === -1) {
                            log.error([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Failed setting "' +
                              type + '" bandwidth as c-line is missing.']);
                            return;
                          }
                      
                          // Follow RFC 4566, that the b-line should follow after c-line.
                          log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Limiting maximum sending "' + type + '" bandwidth ->'], bw);
                          sdpLines.splice(cLineIndex + 1, 0, window.webrtcDetectedBrowser === 'firefox' ? 'b=TIAS:' + (bw * 1024) : 'b=AS:' + bw);
                        };
                      
                        var bASAudioBw = this._streamsBandwidthSettings.bAS.audio;
                        var bASVideoBw = this._streamsBandwidthSettings.bAS.video;
                        var bASDataBw = this._streamsBandwidthSettings.bAS.data;
                        var googleXMinBw = this._streamsBandwidthSettings.googleX.min;
                        var googleXMaxBw = this._streamsBandwidthSettings.googleX.max;
                      
                        if (this._peerCustomConfigs[targetMid]) {
                          if (this._peerCustomConfigs[targetMid].bandwidth &&
                            typeof this._peerCustomConfigs[targetMid].bandwidth === 'object') {
                            if (typeof this._peerCustomConfigs[targetMid].bandwidth.audio === 'number') {
                              bASAudioBw = this._peerCustomConfigs[targetMid].bandwidth.audio;
                            }
                            if (typeof this._peerCustomConfigs[targetMid].bandwidth.video === 'number') {
                              bASVideoBw = this._peerCustomConfigs[targetMid].bandwidth.video;
                            }
                            if (typeof this._peerCustomConfigs[targetMid].bandwidth.data === 'number') {
                              bASDataBw = this._peerCustomConfigs[targetMid].bandwidth.data;
                            }
                          }
                          if (this._peerCustomConfigs[targetMid].googleXBandwidth &&
                            typeof this._peerCustomConfigs[targetMid].googleXBandwidth === 'object') {
                            if (typeof this._peerCustomConfigs[targetMid].googleXBandwidth.min === 'number') {
                              googleXMinBw = this._peerCustomConfigs[targetMid].googleXBandwidth.min;
                            }
                            if (typeof this._peerCustomConfigs[targetMid].googleXBandwidth.max === 'number') {
                              googleXMaxBw = this._peerCustomConfigs[targetMid].googleXBandwidth.max;
                            }
                          }
                        }
                      
                        parseFn('audio', bASAudioBw);
                        parseFn('video', bASVideoBw);
                        parseFn('data', bASDataBw);
                      
                        // Sets the experimental google bandwidth
                        if ((typeof googleXMinBw === 'number') || (typeof googleXMaxBw === 'number')) {
                          var codec = null;
                          var codecRtpMapLineIndex = -1;
                          var codecFmtpLineIndex = -1;
                      
                          for (var j = 0; j < sdpLines.length; j++) {
                            if (sdpLines[j].indexOf('m=video') === 0) {
                              codec = sdpLines[j].split(' ')[3];
                            } else if (codec) {
                              if (sdpLines[j].indexOf('m=') === 0) {
                                break;
                              }
                      
                              if (sdpLines[j].indexOf('a=rtpmap:' + codec + ' ') === 0) {
                                codecRtpMapLineIndex = j;
                              } else if (sdpLines[j].indexOf('a=fmtp:' + codec + ' ') === 0) {
                                sdpLines[j] = sdpLines[j].replace(/x-google-(min|max)-bitrate=[0-9]*[;]*/gi, '');
                                codecFmtpLineIndex = j;
                                break;
                              }
                            }
                          }
                      
                          if (codecRtpMapLineIndex > -1) {
                            var xGoogleParams = '';
                      
                            if (typeof googleXMinBw === 'number') {
                              xGoogleParams += 'x-google-min-bitrate=' + googleXMinBw + ';';
                            }
                      
                            if (typeof googleXMaxBw === 'number') {
                              xGoogleParams += 'x-google-max-bitrate=' + googleXMaxBw + ';';
                            }
                      
                            log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Limiting x-google-bitrate ->'], xGoogleParams);
                      
                            if (codecFmtpLineIndex > -1) {
                              sdpLines[codecFmtpLineIndex] += (sdpLines[codecFmtpLineIndex].split(' ')[1] ? ';' : '') + xGoogleParams;
                            } else {
                              sdpLines.splice(codecRtpMapLineIndex + 1, 0, 'a=fmtp:' + codec + ' ' + xGoogleParams);
                            }
                          }
                        }
                      
                        return sdpLines.join('\r\n');
                      };
                      
                      /**
                       * Function that modifies the session description to set the preferred audio/video codec.
                       * @method _setSDPCodec
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._setSDPCodec = function(targetMid, sessionDescription, overrideSettings) {
                        var self = this;
                        var parseFn = function (type, codecSettings) {
                          var codec = typeof codecSettings === 'object' ? codecSettings.codec : codecSettings;
                          var samplingRate = typeof codecSettings === 'object' ? codecSettings.samplingRate : null;
                          var channels = typeof codecSettings === 'object' ? codecSettings.channels : null;
                      
                          if (codec === self[type === 'audio' ? 'AUDIO_CODEC' : 'VIDEO_CODEC'].AUTO) {
                            log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Not preferring any codec for "' + type + '" streaming. Using browser selection.']);
                            return;
                          }
                      
                          var mLine = sessionDescription.sdp.match(new RegExp('m=' + type + ' .*\r\n', 'gi'));
                      
                          if (!(Array.isArray(mLine) && mLine.length > 0)) {
                            log.error([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Not preferring any codec for "' + type + '" streaming as m= line is not found.']);
                            return;
                          }
                      
                          var setLineFn = function (codecsList, isSROk, isChnlsOk) {
                            if (Array.isArray(codecsList) && codecsList.length > 0) {
                              if (!isSROk) {
                                samplingRate = null;
                              }
                              if (!isChnlsOk) {
                                channels = null;
                              }
                              log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Preferring "' +
                                codec + '" (samplingRate: ' + (samplingRate || 'n/a') + ', channels: ' +
                                (channels || 'n/a') + ') for "' + type + '" streaming.']);
                      
                              var line = mLine[0];
                              var lineParts = line.replace('\r\n', '').split(' ');
                              // Set the m=x x UDP/xxx
                              line = lineParts[0] + ' ' + lineParts[1] + ' ' + lineParts[2] + ' ';
                              // Remove them to leave the codecs only
                              lineParts.splice(0, 3);
                              // Loop for the codecs list to append first
                              for (var i = 0; i < codecsList.length; i++) {
                                var parts = (codecsList[i].split('a=rtpmap:')[1] || '').split(' ');
                                if (parts.length < 2) {
                                  continue;
                                }
                                line += parts[0] + ' ';
                              }
                              // Loop for later fallback codecs to append
                              for (var j = 0; j < lineParts.length; j++) {
                                if (line.indexOf(' ' + lineParts[j]) > 0) {
                                  lineParts.splice(j, 1);
                                  j--;
                                } else if (sessionDescription.sdp.match(new RegExp('a=rtpmap:' + lineParts[j] +
                                  '\ ' + codec + '/.*\r\n', 'gi'))) {
                                  line += lineParts[j] + ' ';
                                  lineParts.splice(j, 1);
                                  j--;
                                }
                              }
                              // Append the rest of the codecs
                              line += lineParts.join(' ') + '\r\n';
                              sessionDescription.sdp = sessionDescription.sdp.replace(mLine[0], line);
                              return true;
                            }
                          };
                      
                          // If samplingRate & channels
                          if (samplingRate) {
                            if (type === 'audio' && channels && setLineFn(sessionDescription.sdp.match(new RegExp('a=rtpmap:.*\ ' +
                              codec + '\/' + samplingRate + (channels === 1 ? '[\/1]*' : '\/' + channels) + '\r\n', 'gi')), true, true)) {
                              return;
                            } else if (setLineFn(sessionDescription.sdp.match(new RegExp('a=rtpmap:.*\ ' + codec + '\/' +
                              samplingRate + '[\/]*.*\r\n', 'gi')), true)) {
                              return;
                            }
                          }
                          if (type === 'audio' && channels && setLineFn(sessionDescription.sdp.match(new RegExp('a=rtpmap:.*\ ' +
                            codec + '\/.*\/' + channels + '\r\n', 'gi')), false, true)) {
                            return;
                          }
                      
                          setLineFn(sessionDescription.sdp.match(new RegExp('a=rtpmap:.*\ ' + codec + '\/.*\r\n', 'gi')));
                        };
                      
                        parseFn('audio', overrideSettings ? overrideSettings.audio : self._selectedAudioCodec);
                        parseFn('video', overrideSettings ? overrideSettings.video : self._selectedVideoCodec);
                      
                        return sessionDescription.sdp;
                      };
                      
                      /**
                       * Function that modifies the session description to remove the previous experimental H264
                       * codec that is apparently breaking connections.
                       * NOTE: We should perhaps not remove it since H264 is supported?
                       * @method _removeSDPFirefoxH264Pref
                       * @private
                       * @for Skylink
                       * @since 0.5.2
                       */
                      Skylink.prototype._removeSDPFirefoxH264Pref = function(targetMid, sessionDescription) {
                        log.info([targetMid, 'RTCSessionDesription', sessionDescription.type,
                          'Removing Firefox experimental H264 flag to ensure interopability reliability']);
                      
                        return sessionDescription.sdp.replace(/a=fmtp:0 profile-level-id=0x42e00c;packetization-mode=1\r\n/g, '');
                      };
                      
                      /**
                       * Function that modifies the session description to append the MediaStream and MediaStreamTrack IDs that seems
                       * to be missing from Firefox answer session description to Chrome connection causing freezes in re-negotiation.
                       * @method _addSDPMediaStreamTrackIDs
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._addSDPMediaStreamTrackIDs = function (targetMid, sessionDescription) {
                        if (!(this._peerConnections[targetMid] && this._peerConnections[targetMid].getLocalStreams().length > 0)) {
                          log.log([targetMid, 'RTCSessionDesription', sessionDescription.type,
                            'Not enforcing MediaStream IDs as no Streams is sent.']);
                          return sessionDescription.sdp;
                        }
                      
                        var sessionDescriptionStr = sessionDescription.sdp;
                      
                        if (!this._enableIceTrickle) {
                          sessionDescriptionStr = sessionDescriptionStr.replace(/a=end-of-candidates\r\n/g, '');
                        }
                      
                        var sdpLines = sessionDescriptionStr.split('\r\n');
                        var agent = ((this._peerInformations[targetMid] || {}).agent || {}).name || '';
                        var localStream = this._peerConnections[targetMid].getLocalStreams()[0];
                        var localStreamId = localStream.id || localStream.label;
                      
                        var parseFn = function (type, tracks) {
                          if (tracks.length === 0) {
                            log.log([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Not enforcing "' + type + '" MediaStreamTrack IDs as no Stream "' + type + '" tracks is sent.']);
                            return;
                          }
                      
                          var trackId = tracks[0].id || tracks[0].label;
                          var trackLabel = tracks[0].label || 'Default';
                          var ssrcId = null;
                          var hasReachedType = false;
                      
                          // Get SSRC ID
                          for (var i = 0; i < sdpLines.length; i++) {
                            if (sdpLines[i].indexOf('m=' + type) === 0) {
                              if (!hasReachedType) {
                                hasReachedType = true;
                                continue;
                              } else {
                                break;
                              }
                            }
                      
                            if (hasReachedType && sdpLines[i].indexOf('a=ssrc:') === 0) {
                              if (!ssrcId) {
                                ssrcId = (sdpLines[i].split(':')[1] || '').split(' ')[0] || null;
                              }
                      
                              if (ssrcId && sdpLines[i].indexOf('a=ssrc:' + ssrcId + ' ') === 0) {
                                if (sdpLines[i].indexOf(' cname:') > 0) {
                                  log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Updating MediaStreamTrack ssrc (' +
                                    ssrcId + ') for "' + localStreamId + '" stream and "' + trackId + '" (label:"' + trackLabel + '")']);
                                  sdpLines.splice(i + 1, 0,
                                    'a=ssrc:' + ssrcId + ' msid:' + localStreamId + ' ' + trackId,
                                    'a=ssrc:' + ssrcId + ' mslabel:' + trackId,
                                    'a=ssrc:' + ssrcId + ' label:' + trackId);
                                  i += 3;
                                } else {
                                  sdpLines.splice(i, 1);
                                  i--;
                                }
                              }
                              break;
                            }
                          }
                        };
                      
                        parseFn('audio', localStream.getAudioTracks());
                        parseFn('video', localStream.getVideoTracks());
                      
                        // Append signaling of end-of-candidates
                        if (!this._enableIceTrickle){
                          log.info([targetMid, 'RTCSessionDesription', sessionDescription.type,
                            'Appending end-of-candidates signal for non-trickle ICE connection.']);
                          for (var i = 0; i < sdpLines.length; i++) {
                            if (sdpLines[i].indexOf('a=candidate:') === 0) {
                              if (sdpLines[i + 1] ? !(sdpLines[i + 1].indexOf('a=candidate:') === 0 ||
                                sdpLines[i + 1].indexOf('a=end-of-candidates') === 0) : true) {
                                sdpLines.splice(i + 1, 0, 'a=end-of-candidates');
                                i++;
                              }
                            }
                          }
                        }
                      
                        if (sessionDescription.type === this.HANDSHAKE_PROGRESS.ANSWER && this._sdpSessions[targetMid]) {
                          var bundleLineIndex = -1;
                          var mLineIndex = -1;
                      
                          for (var j = 0; j < sdpLines.length; j++) {
                            if (sdpLines[j].indexOf('a=group:BUNDLE') === 0 && this._sdpSessions[targetMid].remote.bundleLine &&
                              this._peerConnectionConfig.bundlePolicy === this.BUNDLE_POLICY.MAX_BUNDLE) {
                              sdpLines[j] = this._sdpSessions[targetMid].remote.bundleLine;
                            } else if (sdpLines[j].indexOf('m=') === 0) {
                              mLineIndex++;
                              var compareA = sdpLines[j].split(' ');
                              var compareB = (this._sdpSessions[targetMid].remote.mLines[mLineIndex] || '').split(' ');
                      
                              if (compareA[0] && compareB[0] && compareA[0] !== compareB[0]) {
                                compareB[1] = 0;
                                log.info([targetMid, 'RTCSessionDesription', sessionDescription.type,
                                  'Appending middle rejected m= line ->'], compareB.join(' '));
                                sdpLines.splice(j, 0, compareB.join(' '));
                                j++;
                                mLineIndex++;
                              }
                            }
                          }
                      
                          while (this._sdpSessions[targetMid].remote.mLines[mLineIndex + 1]) {
                            mLineIndex++;
                            var appendIndex = sdpLines.length;
                            if (!sdpLines[appendIndex - 1].replace(/\s/gi, '')) {
                              appendIndex -= 1;
                            }
                            var parts = (this._sdpSessions[targetMid].remote.mLines[mLineIndex] || '').split(' ');
                            parts[1] = 0;
                            log.info([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Appending later rejected m= line ->'], parts.join(' '));
                            sdpLines.splice(appendIndex, 0, parts.join(' '));
                          }
                        }
                      
                        if (window.webrtcDetectedBrowser === 'edge' && sessionDescription.type === this.HANDSHAKE_PROGRESS.OFFER &&
                          !sdpLines[sdpLines.length - 1].replace(/\s/gi, '')) {
                          log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Removing last empty space for Edge browsers']);
                          sdpLines.splice(sdpLines.length - 1, 1);
                        }
                      
                        var outputStr = sdpLines.join('\r\n');
                      
                        /*if (window.webrtcDetectedBrowser === 'edge' && this._streams.userMedia && this._streams.userMedia.stream) {
                          var correctStreamId = this._streams.userMedia.stream.id || this._streams.userMedia.stream.label;
                          outputStr = outputStr.replace(new RegExp('a=msid:.*\ ', 'gi'), 'a=msid:' + correctStreamId + ' ');
                          outputStr = outputStr.replace(new RegExp('\ msid:.*\ ', 'gi'), ' msid:' + correctStreamId + ' ');
                        }*/
                      
                        return outputStr;
                      };
                      
                      /**
                       * Function that modifies the session description to remove apt/rtx lines that does exists.
                       * @method _removeSDPUnknownAptRtx
                       * @private
                       * @for Skylink
                       * @since 0.6.18
                       */
                      Skylink.prototype._removeSDPUnknownAptRtx = function (targetMid, sessionDescription) {
                        var codecsPayload = []; // Payload numbers as the keys
                        var sdpLines = sessionDescription.sdp.split('\r\n');
                        var hasVideo = false;
                        var rtxs = {};
                        var parts = [];
                      
                        // Remove rtx or apt= lines that prevent connections for browsers without VP8 or VP9 support
                        // See: https://bugs.chromium.org/p/webrtc/issues/detail?id=3962
                        for (var i = 0; i < sdpLines.length; i++) {
                          if (sdpLines[i].indexOf('m=') === 0) {
                            if (hasVideo) {
                              for (var r in rtxs) {
                                if (rtxs.hasOwnProperty(r) && rtxs[r] && codecsPayload.indexOf(rtxs[r].codec) === -1) {
                                  for (var l = 0; l < rtxs[r].lines.length; l++) {
                                    sdpLines.splice(sdpLines.indexOf(rtxs[r].lines[l]), 1);
                                    i--;
                                  }
                                }
                              }
                            }
                            hasVideo = sdpLines[i].indexOf('m=video ') === 0;
                            codecsPayload = [];
                            rtxs = {};
                          }
                          if (sdpLines[i].toLowerCase().indexOf('a=rtpmap:') === 0) {
                            parts = (sdpLines[i].split('a=rtpmap:')[1] || '').split(' ');
                            if (parts[1].toLowerCase().indexOf('rtx') === 0) {
                              if (!rtxs[parts[0]]) {
                                rtxs[parts[0]] = { lines:[], codec: null };
                              }
                              rtxs[parts[0]].lines.push(sdpLines[i]);
                            } else {
                              codecsPayload.push(parts[0]);
                            }
                          } else if (sdpLines[i].indexOf('a=fmtp:') === 0 && sdpLines[i].indexOf(' apt=') > 0) {
                            parts = (sdpLines[i].split('a=fmtp:')[1] || '').split(' ');
                            if (parts[0] && !rtxs[parts[0]]) {
                              rtxs[parts[0]] = { lines:[], codec: null };
                            }
                            rtxs[parts[0]].codec = parts[1].split('apt=')[1];
                            rtxs[parts[0]].lines.push(sdpLines[i]);
                          }
                        }
                      
                        return sdpLines.join('\r\n');
                      };
                      
                      /**
                       * Function that modifies the session description to remove codecs.
                       * @method _removeSDPCodecs
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._removeSDPCodecs = function (targetMid, sessionDescription) {
                        var audioSettings = this.getPeerInfo().settings.audio;
                      
                        var parseFn = function (type, codec) {
                          var payloadList = sessionDescription.sdp.match(new RegExp('a=rtpmap:(\\d*)\\ ' + codec + '.*', 'gi'));
                      
                          if (!(Array.isArray(payloadList) && payloadList.length > 0)) {
                            log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Not removing "' + codec + '" as it does not exists.']);
                            return;
                          }
                      
                          for (var i = 0; i < payloadList.length; i++) {
                            var payload = payloadList[i].split(' ')[0].split(':')[1];
                      
                            log.info([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Removing "' + codec + '" payload ->'], payload);
                      
                            sessionDescription.sdp = sessionDescription.sdp.replace(
                              new RegExp('a=rtpmap:' + payload + '\\ .*\\r\\n', 'g'), '');
                            sessionDescription.sdp = sessionDescription.sdp.replace(
                              new RegExp('a=fmtp:' + payload + '\\ .*\\r\\n', 'g'), '');
                            sessionDescription.sdp = sessionDescription.sdp.replace(
                              new RegExp('a=rtpmap:\\d+ rtx\\/\\d+\\r\\na=fmtp:\\d+ apt=' + payload + '\\r\\n', 'g'), '');
                      
                            // Remove the m-line codec
                            var sdpLines = sessionDescription.sdp.split('\r\n');
                      
                            for (var j = 0; j < sdpLines.length; j++) {
                              if (sdpLines[j].indexOf('m=' + type) === 0) {
                                var parts = sdpLines[j].split(' ');
                      
                                if (parts.indexOf(payload) >= 3) {
                                  parts.splice(parts.indexOf(payload), 1);
                                }
                      
                                sdpLines[j] = parts.join(' ');
                                break;
                              }
                            }
                      
                            sessionDescription.sdp = sdpLines.join('\r\n');
                          }
                        };
                      
                        if (this._disableVideoFecCodecs) {
                          if (this._hasMCU) {
                            log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type,
                              'Not removing "ulpfec" or "red" codecs as connected to MCU to prevent connectivity issues.']);
                          } else {
                            parseFn('video', 'red');
                            parseFn('video', 'ulpfec');
                          }
                        }
                      
                        if (this._disableComfortNoiseCodec && audioSettings && typeof audioSettings === 'object' && audioSettings.stereo) {
                          parseFn('audio', 'CN');
                        }
                      
                        if (window.webrtcDetectedBrowser === 'edge' &&
                          (((this._peerInformations[targetMid] || {}).agent || {}).name || 'unknown').name !== 'edge') {
                          sessionDescription.sdp = sessionDescription.sdp.replace(/a=rtcp-fb:.*\ x-message\ .*\r\n/gi, '');
                        }
                      
                        return sessionDescription.sdp;
                      };
                      
                      /**
                       * Function that modifies the session description to remove REMB packets fb.
                       * @method _removeSDPREMBPackets
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._removeSDPREMBPackets = function (targetMid, sessionDescription) {
                        if (!this._disableREMB) {
                          return sessionDescription.sdp;
                        }
                      
                        log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Removing REMB packets.']);
                        return sessionDescription.sdp.replace(/a=rtcp-fb:\d+ goog-remb\r\n/g, '');
                      };
                      
                      /**
                       * Function that retrieves the session description selected codec.
                       * @method _getSDPSelectedCodec
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._getSDPSelectedCodec = function (targetMid, sessionDescription, type, beSilentOnLogs) {
                        if (!(sessionDescription && sessionDescription.sdp)) {
                          return null;
                        }
                      
                        var sdpLines = sessionDescription.sdp.split('\r\n');
                        var selectedCodecInfo = {
                          name: null,
                          implementation: null,
                          clockRate: null,
                          channels: null,
                          payloadType: null,
                          params: null
                        };
                      
                        for (var i = 0; i < sdpLines.length; i++) {
                          if (sdpLines[i].indexOf('m=' + type) === 0) {
                            var parts = sdpLines[i].split(' ');
                      
                            if (parts.length < 4) {
                              break;
                            }
                      
                            selectedCodecInfo.payloadType = parseInt(parts[3], 10);
                      
                          } else if (selectedCodecInfo.payloadType !== null) {
                            if (sdpLines[i].indexOf('m=') === 0) {
                              break;
                            }
                      
                            if (sdpLines[i].indexOf('a=rtpmap:' + selectedCodecInfo.payloadType + ' ') === 0) {
                              var params = (sdpLines[i].split(' ')[1] || '').split('/');
                              selectedCodecInfo.name = params[0] || '';
                              selectedCodecInfo.clockRate = params[1] ? parseInt(params[1], 10) : null;
                              selectedCodecInfo.channels = params[2] ? parseInt(params[2], 10) : null;
                      
                            } else if (sdpLines[i].indexOf('a=fmtp:' + selectedCodecInfo.payloadType + ' ') === 0) {
                              selectedCodecInfo.params = sdpLines[i].split('a=fmtp:' + selectedCodecInfo.payloadType + ' ')[1] || null;
                            }
                          }
                        }
                      
                        if (!beSilentOnLogs) {
                          log.debug([targetMid, 'RTCSessionDesription', sessionDescription.type,
                            'Parsing session description "' + type + '" codecs ->'], selectedCodecInfo);
                        }
                      
                        return selectedCodecInfo;
                      };
                      
                      /**
                       * Function that modifies the session description to remove non-relay ICE candidates.
                       * @method _removeSDPFilteredCandidates
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._removeSDPFilteredCandidates = function (targetMid, sessionDescription) {
                        // Handle Firefox MCU Peer ICE candidates
                        if (targetMid === 'MCU' && sessionDescription.type === this.HANDSHAKE_PROGRESS.ANSWER &&
                          window.webrtcDetectedBrowser === 'firefox') {
                          sessionDescription.sdp = sessionDescription.sdp.replace(/ generation 0/g, '');
                          sessionDescription.sdp = sessionDescription.sdp.replace(/ udp /g, ' UDP ');
                        }
                      
                        if (this._forceTURN && this._hasMCU) {
                          log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Not filtering ICE candidates as ' +
                            'TURN connections are enforced as MCU is present (and act as a TURN itself) so filtering of ICE candidate ' +
                            'flags are not honoured']);
                          return sessionDescription.sdp;
                        }
                      
                        if (this._filterCandidatesType.host) {
                          log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Removing "host" ICE candidates.']);
                          sessionDescription.sdp = sessionDescription.sdp.replace(/a=candidate:.*host.*\r\n/g, '');
                        }
                      
                        if (this._filterCandidatesType.srflx) {
                          log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Removing "srflx" ICE candidates.']);
                          sessionDescription.sdp = sessionDescription.sdp.replace(/a=candidate:.*srflx.*\r\n/g, '');
                        }
                      
                        if (this._filterCandidatesType.relay) {
                          log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Removing "relay" ICE candidates.']);
                          sessionDescription.sdp = sessionDescription.sdp.replace(/a=candidate:.*relay.*\r\n/g, '');
                        }
                      
                        // sessionDescription.sdp = sessionDescription.sdp.replace(/a=candidate:(?!.*relay.*).*\r\n/g, '');
                      
                        return sessionDescription.sdp;
                      };
                      
                      /**
                       * Function that retrieves the current list of support codecs.
                       * @method _getCodecsSupport
                       * @private
                       * @for Skylink
                       * @since 0.6.18
                       */
                      Skylink.prototype._getCodecsSupport = function (callback) {
                        var self = this;
                      
                        if (self._currentCodecSupport) {
                          callback(null);
                        }
                      
                        self._currentCodecSupport = { audio: {}, video: {} };
                      
                        try {
                          if (window.webrtcDetectedBrowser === 'edge') {
                            var codecs = RTCRtpSender.getCapabilities().codecs;
                      
                            for (var i = 0; i < codecs.length; i++) {
                              if (['audio','video'].indexOf(codecs[i].kind) > -1 && codecs[i].name) {
                                var codec = codecs[i].name.toLowerCase();
                                self._currentCodecSupport[codecs[i].kind][codec] = codecs[i].clockRate +
                                  (codecs[i].numChannels > 1 ? '/' + codecs[i].numChannels : '');
                              }
                            }
                            // Ignore .fecMechanisms for now
                            callback(null);
                      
                          } else {
                            var pc = new RTCPeerConnection(null);
                            var offerConstraints = {
                              offerToReceiveAudio: true,
                              offerToReceiveVideo: true
                            };
                      
                            if (['IE', 'safari'].indexOf(window.webrtcDetectedBrowser) > -1) {
                              offerConstraints = {
                                mandatory: {
                                  OfferToReceiveVideo: true,
                                  OfferToReceiveAudio: true
                                }
                              };
                            }
                      
                            // Prevent errors and proceed with create offer still...
                            try {
                              var channel = pc.createDataChannel('test');
                              self._binaryChunkType = channel.binaryType || self._binaryChunkType;
                              self._binaryChunkType = self._binaryChunkType.toLowerCase().indexOf('array') > -1 ?
                                self.DATA_TRANSFER_DATA_TYPE.ARRAY_BUFFER : self._binaryChunkType;
                              // Set the value according to the property
                              for (var prop in self.DATA_TRANSFER_DATA_TYPE) {
                                if (self.DATA_TRANSFER_DATA_TYPE.hasOwnProperty(prop) &&
                                  self._binaryChunkType.toLowerCase() === self.DATA_TRANSFER_DATA_TYPE[prop].toLowerCase()) {
                                  self._binaryChunkType = self.DATA_TRANSFER_DATA_TYPE[prop];
                                  break;
                                }
                              }
                            } catch (e) {}
                      
                            pc.createOffer(function (offer) {
                              var sdpLines = offer.sdp.split('\r\n');
                              var mediaType = '';
                      
                              for (var i = 0; i < sdpLines.length; i++) {
                                if (sdpLines[i].indexOf('m=') === 0) {
                                  mediaType = (sdpLines[i].split('m=')[1] || '').split(' ')[0];
                                } else if (sdpLines[i].indexOf('a=rtpmap:') === 0) {
                                  if (['audio', 'video'].indexOf(mediaType) === -1) {
                                    continue;
                                  }
                                  var parts = (sdpLines[i].split(' ')[1] || '').split('/');
                                  var codec = (parts[0] || '').toLowerCase();
                                  var info = parts[1] + (parts[2] ? '/' + parts[2] : '');
                      
                                  self._currentCodecSupport[mediaType][codec] = info;
                                }
                              }
                      
                              callback(null);
                      
                            }, function (error) {
                              callback(error);
                            }, offerConstraints);
                          }
                        } catch (error) {
                          callback(error);
                        }
                      };
                      
                      /**
                       * Function that modifies the session description to handle the connection settings.
                       * This is experimental and never recommended to end-users.
                       * @method _handleSDPConnectionSettings
                       * @private
                       * @for Skylink
                       * @since 0.6.16
                       */
                      Skylink.prototype._handleSDPConnectionSettings = function (targetMid, sessionDescription, direction) {
                        var self = this;
                      
                        if (!self._sdpSessions[targetMid]) {
                          return sessionDescription.sdp;
                        }
                      
                        var sessionDescriptionStr = sessionDescription.sdp;
                      
                        if (direction === 'remote' && !self.getPeerInfo(targetMid).config.enableIceTrickle) {
                          sessionDescriptionStr = sessionDescriptionStr.replace(/a=end-of-candidates\r\n/g, '');
                        }
                      
                        var sdpLines = sessionDescriptionStr.split('\r\n');
                        var peerAgent = ((self._peerInformations[targetMid] || {}).agent || {}).name || '';
                        var mediaType = '';
                        var bundleLineIndex = -1;
                        var bundleLineMids = [];
                        var mLineIndex = -1;
                        var settings = clone(self._sdpSettings);
                      
                        if (targetMid === 'MCU') {
                          settings.connection.audio = true;
                          settings.connection.video = true;
                          settings.connection.data = true;
                        }
                      
                        if (settings.connection.video) {
                          settings.connection.video = (window.webrtcDetectedBrowser === 'edge' && peerAgent !== 'edge') ||
                            (['IE', 'safari'].indexOf(window.webrtcDetectedBrowser) > -1 && peerAgent === 'edge') ?
                            !!self._currentCodecSupport.video.h264 : true;
                        }
                      
                        if (self._hasMCU) {
                          settings.direction.audio.receive = targetMid === 'MCU' ? false : true;
                          settings.direction.audio.send = targetMid === 'MCU' ? true : false;
                          settings.direction.video.receive = targetMid === 'MCU' ? false : true;
                          settings.direction.video.send = targetMid === 'MCU' ? true : false;
                        }
                      
                        // ANSWERER: Reject only the m= lines. Returned rejected m= lines as well.
                        // OFFERER: Remove m= lines
                      
                        self._sdpSessions[targetMid][direction].mLines = [];
                        self._sdpSessions[targetMid][direction].bundleLine = '';
                      
                        for (var i = 0; i < sdpLines.length; i++) {
                          // Cache the a=group:BUNDLE line used for remote answer from Edge later
                          if (sdpLines[i].indexOf('a=group:BUNDLE') === 0) {
                            self._sdpSessions[targetMid][direction].bundleLine = sdpLines[i];
                            bundleLineIndex = i;
                      
                          // Check if there's a need to reject m= line
                          } else if (sdpLines[i].indexOf('m=') === 0) {
                            mediaType = (sdpLines[i].split('m=')[1] || '').split(' ')[0] || '';
                            mediaType = mediaType === 'application' ? 'data' : mediaType;
                            mLineIndex++;
                      
                            self._sdpSessions[targetMid][direction].mLines[mLineIndex] = sdpLines[i];
                      
                            // Check if there is missing unsupported video codecs support and reject it regardles of MCU Peer or not
                            if (!settings.connection[mediaType]) {
                              log.log([targetMid, 'RTCSessionDesription', sessionDescription.type,
                                'Removing rejected m=' + mediaType + ' line ->'], sdpLines[i]);
                      
                              // Check if answerer and we do not have the power to remove the m line if index is 0
                              // Set as a=inactive because we do not have that power to reject it somehow..
                              // first m= line cannot be rejected for BUNDLE
                              if (self._peerConnectionConfig.bundlePolicy === self.BUNDLE_POLICY.MAX_BUNDLE &&
                                bundleLineIndex > -1 && mLineIndex === 0 && (direction === 'remote' ?
                                sessionDescription.type === this.HANDSHAKE_PROGRESS.OFFER :
                                sessionDescription.type === this.HANDSHAKE_PROGRESS.ANSWER)) {
                                log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type,
                                  'Not removing rejected m=' + mediaType + ' line ->'], sdpLines[i]);
                                settings.connection[mediaType] = true;
                                if (['audio', 'video'].indexOf(mediaType) > -1) {
                                  settings.direction[mediaType].send = false;
                                  settings.direction[mediaType].receive = false;
                                }
                                continue;
                              }
                      
                              if (window.webrtcDetectedBrowser === 'edge') {
                                sdpLines.splice(i, 1);
                                i--;
                                continue;
                              } else if (direction === 'remote' || sessionDescription.type === this.HANDSHAKE_PROGRESS.ANSWER) {
                                var parts = sdpLines[i].split(' ');
                                parts[1] = 0;
                                sdpLines[i] = parts.join(' ');
                                continue;
                              }
                            }
                          }
                      
                          if (direction === 'remote' && sdpLines[i].indexOf('a=candidate:') === 0 &&
                            !self.getPeerInfo(targetMid).config.enableIceTrickle) {
                            if (sdpLines[i + 1] ? !(sdpLines[i + 1].indexOf('a=candidate:') === 0 ||
                              sdpLines[i + 1].indexOf('a=end-of-candidates') === 0) : true) {
                              log.info([targetMid, 'RTCSessionDesription', sessionDescription.type,
                                'Appending end-of-candidates signal for non-trickle ICE connection.']);
                              sdpLines.splice(i + 1, 0, 'a=end-of-candidates');
                              i++;
                            }
                          }
                      
                          if (mediaType) {
                            // Remove lines if we are rejecting the media and ensure unless (rejectVideoMedia is true), MCU has to enable those m= lines
                            if (!settings.connection[mediaType]) {
                              sdpLines.splice(i, 1);
                              i--;
                      
                            // Store the mids session description
                            } else if (sdpLines[i].indexOf('a=mid:') === 0) {
                              bundleLineMids.push(sdpLines[i].split('a=mid:')[1] || '');
                      
                            // Configure direction a=sendonly etc for local sessiondescription
                            }  else if (direction === 'local' && mediaType && ['audio', 'video'].indexOf(mediaType) > -1 &&
                              ['a=sendrecv', 'a=sendonly', 'a=recvonly'].indexOf(sdpLines[i]) > -1) {
                      
                              if (settings.direction[mediaType].send && !settings.direction[mediaType].receive) {
                                sdpLines[i] = sdpLines[i].indexOf('send') > -1 ? 'a=sendonly' : 'a=inactive';
                              } else if (!settings.direction[mediaType].send && settings.direction[mediaType].receive) {
                                sdpLines[i] = sdpLines[i].indexOf('recv') > -1 ? 'a=recvonly' : 'a=inactive';
                              } else if (!settings.direction[mediaType].send && !settings.direction[mediaType].receive) {
                              // MCU currently does not support a=inactive flag.. what do we do here?
                                sdpLines[i] = 'a=inactive';
                              }
                      
                              // Handle Chrome bundle bug. - See: https://bugs.chromium.org/p/webrtc/issues/detail?id=6280
                              if (!self._hasMCU && window.webrtcDetectedBrowser !== 'firefox' && peerAgent === 'firefox' &&
                                sessionDescription.type === self.HANDSHAKE_PROGRESS.OFFER && sdpLines[i] === 'a=recvonly') {
                                log.warn([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Overriding any original settings ' +
                                  'to receive only to send and receive to resolve chrome BUNDLE errors.']);
                                sdpLines[i] = 'a=sendrecv';
                                settings.direction[mediaType].send = true;
                                settings.direction[mediaType].receive = true;
                              }
                            }
                          }
                      
                          // Remove weird empty characters for Edge case.. :(
                          if (!(sdpLines[i] || '').replace(/\n|\r|\s|\ /gi, '')) {
                            sdpLines.splice(i, 1);
                            i--;
                          }
                        }
                      
                        // Fix chrome "offerToReceiveAudio" local offer not removing audio BUNDLE
                        if (bundleLineIndex > -1) {
                          if (self._peerConnectionConfig.bundlePolicy === self.BUNDLE_POLICY.MAX_BUNDLE) {
                            sdpLines[bundleLineIndex] = 'a=group:BUNDLE ' + bundleLineMids.join(' ');
                          // Remove a=group:BUNDLE line
                          } else if (self._peerConnectionConfig.bundlePolicy === self.BUNDLE_POLICY.NONE) {
                            sdpLines.splice(bundleLineIndex, 1);
                          }
                        }
                      
                        // Append empty space below
                        if (window.webrtcDetectedBrowser !== 'edge') {
                          if (!sdpLines[sdpLines.length - 1].replace(/\n|\r|\s/gi, '')) {
                            sdpLines[sdpLines.length - 1] = '';
                          } else {
                            sdpLines.push('');
                          }
                        }
                      
                        log.info([targetMid, 'RTCSessionDesription', sessionDescription.type, 'Handling connection lines and direction ->'], settings);
                      
                        return sdpLines.join('\r\n');
                      };
                      
                      /**
                       * Function that parses and retrieves the session description fingerprint.
                       * @method _getSDPFingerprint
                       * @private
                       * @for Skylink
                       * @since 0.6.18
                       */
                      Skylink.prototype._getSDPFingerprint = function (targetMid, sessionDescription, beSilentOnLogs) {
                        var fingerprint = {
                          fingerprint: null,
                          fingerprintAlgorithm: null,
                          derBase64: null
                        };
                      
                        if (!(sessionDescription && sessionDescription.sdp)) {
                          return fingerprint;
                        }
                      
                        var sdpLines = sessionDescription.sdp.split('\r\n');
                      
                        for (var i = 0; i < sdpLines.length; i++) {
                          if (sdpLines[i].indexOf('a=fingerprint') === 0) {
                            var parts = sdpLines[i].replace('a=fingerprint:', '').split(' ');
                            fingerprint.fingerprint = parts[1];
                            fingerprint.fingerprintAlgorithm = parts[0];
                            break;
                          }
                        }
                      
                        if (!beSilentOnLogs) {
                          log.debug([targetMid, 'RTCSessionDesription', sessionDescription.type,
                            'Parsing session description fingerprint ->'], fingerprint);
                        }
                      
                        return fingerprint;
                      };