Refactors simulcast support.

app.js

         this.connectionquality = require("./modules/connectionquality/connectionquality");
         this.statistics = require("./modules/statistics/statistics");
         this.RTC = require("./modules/RTC/RTC");
-        this.simulcast = require("./modules/simulcast/simulcast");
         this.desktopsharing = require("./modules/desktopsharing/desktopsharing");
         this.xmpp = require("./modules/xmpp/xmpp");
         this.keyboardshortcut = require("./modules/keyboardshortcut/keyboardshortcut");

modules/RTC/DataChannels.js

                     eventEmitter.emit(RTCEvents.LASTN_ENDPOINT_CHANGED,
                         lastNEndpoints, endpointsEnteringLastN, obj);
                 }
-                else if ("SimulcastLayersChangedEvent" === colibriClass)
-                {
-                    eventEmitter.emit(RTCEvents.SIMULCAST_LAYER_CHANGED,
-                        obj.endpointSimulcastLayers);
-                }
-                else if ("SimulcastLayersChangingEvent" === colibriClass)
-                {
-                    eventEmitter.emit(RTCEvents.SIMULCAST_LAYER_CHANGING,
-                        obj.endpointSimulcastLayers);
-                }
-                else if ("StartSimulcastLayerEvent" === colibriClass)
-                {
-                    eventEmitter.emit(RTCEvents.SIMULCAST_START, obj.simulcastLayer);
-                }
-                else if ("StopSimulcastLayerEvent" === colibriClass)
-                {
-                    eventEmitter.emit(RTCEvents.SIMULCAST_STOP, obj.simulcastLayer);
-                }
                 else
                 {
                     console.debug("Data channel JSON-formatted message: ", obj);

modules/RTC/RTCUtils.js

         console.log('This appears to be Firefox');
         var version = parseInt(navigator.userAgent.match(/Firefox\/([0-9]+)\./)[1], 10);
         if (version >= 40
-            && !config.enableSimulcast && config.useBundle && config.useRtcpMux) {
+            && config.useBundle && config.useRtcpMux) {
             this.peerconnection = mozRTCPeerConnection;
             this.browser = RTCBrowserType.RTC_BROWSER_FIREFOX;
             this.getUserMedia = navigator.mozGetUserMedia.bind(navigator);
     var self = this;
 
     try {
-        if (config.enableSimulcast
-            && constraints.video
-            && constraints.video.chromeMediaSource !== 'screen'
-            && constraints.video.chromeMediaSource !== 'desktop'
-            && !isAndroid
-
-            // We currently do not support FF, as it doesn't have multistream support.
-            && !isFF) {
-            APP.simulcast.getUserMedia(constraints, function (stream) {
-                    console.log('onUserMediaSuccess');
-                    self.setAvailableDevices(um, true);
-                    success_callback(stream);
-                },
-                function (error) {
-                    console.warn('Failed to get access to local media. Error ', error);
-                    self.setAvailableDevices(um, false);
-                    if (failure_callback) {
-                        failure_callback(error);
-                    }
-                });
-        } else {
-
-            this.getUserMedia(constraints,
-                function (stream) {
-                    console.log('onUserMediaSuccess');
-                    self.setAvailableDevices(um, true);
-                    success_callback(stream);
-                },
-                function (error) {
-                    self.setAvailableDevices(um, false);
-                    console.warn('Failed to get access to local media. Error ',
-                        error, constraints);
-                    if (failure_callback) {
-                        failure_callback(error);
-                    }
-                });
-
-        }
+        this.getUserMedia(constraints,
+            function (stream) {
+                console.log('onUserMediaSuccess');
+                self.setAvailableDevices(um, true);
+                success_callback(stream);
+            },
+            function (error) {
+                self.setAvailableDevices(um, false);
+                console.warn('Failed to get access to local media. Error ',
+                    error, constraints);
+                if (failure_callback) {
+                    failure_callback(error);
+                }
+            });
     } catch (e) {
         console.error('GUM failed: ', e);
         if(failure_callback) {

modules/UI/UI.js

             VideoLayout.onLastNEndpointsChanged(lastNEndpoints,
                 endpointsEnteringLastN, stream);
         });
-    APP.RTC.addListener(RTCEvents.SIMULCAST_LAYER_CHANGED,
-        function (endpointSimulcastLayers) {
-           VideoLayout.onSimulcastLayersChanged(endpointSimulcastLayers);
-        });
-    APP.RTC.addListener(RTCEvents.SIMULCAST_LAYER_CHANGING,
-        function (endpointSimulcastLayers) {
-            VideoLayout.onSimulcastLayersChanging(endpointSimulcastLayers);
-        });
     APP.RTC.addListener(RTCEvents.AVAILABLE_DEVICES_CHANGED,
         function (devices) {
             VideoLayout.setDeviceAvailabilityIcons(null, devices);

modules/UI/videolayout/ConnectionIndicator.js

     if(this.resolution && this.jid != null)
     {
         var keys = Object.keys(this.resolution);
-        if(keys.length == 1)
+        for(var ssrc in this.resolution)
         {
-            for(var ssrc in this.resolution)
-            {
-                resolutionValue = this.resolution[ssrc];
-            }
-        }
-        else if(keys.length > 1)
-        {
-            var displayedSsrc = APP.simulcast.getReceivingSSRC(this.jid);
-            resolutionValue = this.resolution[displayedSsrc];
+            resolutionValue = this.resolution[ssrc];
         }
     }
 

modules/UI/videolayout/VideoLayout.js

     if (stream.id === 'mixedmslabel') return;
 
     if (selector[0].currentTime > 0) {
-        var videoStream = APP.simulcast.getReceivingVideoStream(stream);
-        APP.RTC.attachMediaStream(selector, videoStream); // FIXME: why do i have to do this for FF?
+        APP.RTC.attachMediaStream(selector, stream); // FIXME: why do i have to do this for FF?
         videoactive(selector);
     } else {
         setTimeout(function () {
         }
 
         // Attach WebRTC stream
-        var videoStream = APP.simulcast.getLocalVideoStream();
-        APP.RTC.attachMediaStream(localVideoSelector, videoStream);
+        APP.RTC.attachMediaStream(localVideoSelector, stream.getOriginalStream());
 
         // Add stream ended handler
         stream.getOriginalStream().onended = function () {
             // Screen stream is already rotated
             largeVideoState.flipX = (newSrc === localVideoSrc) && flipXLocalVideo;
 
-            var userChanged = false;
             if (largeVideoState.oldResourceJid !== largeVideoState.userResourceJid) {
-                userChanged = true;
                 // we want the notification to trigger even if userJid is undefined,
                 // or null.
                 eventEmitter.emit(UIEvents.SELECTED_ENDPOINT,
                     largeVideoState.userResourceJid);
             }
 
-            if (!largeVideoState.updateInProgress) {
-                largeVideoState.updateInProgress = true;
-
-                var doUpdate = function () {
-                    Avatar.updateActiveSpeakerAvatarSrc(
-                        APP.xmpp.findJidFromResource(
-                            largeVideoState.userResourceJid));
-
-                    if (!userChanged && largeVideoState.preload &&
-                        largeVideoState.preload !== null &&
-                        APP.RTC.getVideoSrc($(largeVideoState.preload)[0]) === newSrc)
-                    {
-
-                        console.info('Switching to preloaded video');
-                        var attributes = $('#largeVideo').prop("attributes");
-
-                        // loop through largeVideo attributes and apply them on
-                        // preload.
-                        $.each(attributes, function () {
-                            if (this.name !== 'id' && this.name !== 'src') {
-                                largeVideoState.preload.attr(this.name, this.value);
-                            }
-                        });
-
-                        largeVideoState.preload.appendTo($('#largeVideoContainer'));
-                        $('#largeVideo').attr('id', 'previousLargeVideo');
-                        largeVideoState.preload.attr('id', 'largeVideo');
-                        $('#previousLargeVideo').remove();
-
-                        largeVideoState.preload.on('loadedmetadata', function (e) {
-                            currentVideoWidth = this.videoWidth;
-                            currentVideoHeight = this.videoHeight;
-                            VideoLayout.positionLarge(currentVideoWidth, currentVideoHeight);
-                        });
-                        largeVideoState.preload = null;
-                        largeVideoState.preload_ssrc = 0;
-                    } else {
-                        APP.RTC.setVideoSrc($('#largeVideo')[0], largeVideoState.newSrc);
-                    }
-
-                    var videoTransform = document.getElementById('largeVideo')
-                        .style.webkitTransform;
-
-                    if (largeVideoState.flipX && videoTransform !== 'scaleX(-1)') {
-                        document.getElementById('largeVideo').style.webkitTransform
-                            = "scaleX(-1)";
-                    }
-                    else if (!largeVideoState.flipX && videoTransform === 'scaleX(-1)') {
-                        document.getElementById('largeVideo').style.webkitTransform
-                            = "none";
-                    }
+            $('#largeVideo').fadeOut(300, function () {
+                Avatar.updateActiveSpeakerAvatarSrc(
+                    APP.xmpp.findJidFromResource(
+                        largeVideoState.userResourceJid));
 
-                    // Change the way we'll be measuring and positioning large video
+                APP.RTC.setVideoSrc($('#largeVideo')[0], largeVideoState.newSrc);
 
-                    VideoLayout.getVideoSize = largeVideoState.isDesktop
-                        ? getDesktopVideoSize
-                        : getCameraVideoSize;
-                    VideoLayout.getVideoPosition = largeVideoState.isDesktop
-                        ? getDesktopVideoPosition
-                        : getCameraVideoPosition;
+                var videoTransform = document.getElementById('largeVideo')
+                    .style.webkitTransform;
 
+                if (largeVideoState.flipX && videoTransform !== 'scaleX(-1)') {
+                    document.getElementById('largeVideo').style.webkitTransform
+                        = "scaleX(-1)";
+                }
+                else if (!largeVideoState.flipX && videoTransform === 'scaleX(-1)') {
+                    document.getElementById('largeVideo').style.webkitTransform
+                        = "none";
+                }
 
-                    // Only if the large video is currently visible.
-                    // Disable previous dominant speaker video.
-                    if (largeVideoState.oldResourceJid) {
-                        VideoLayout.enableDominantSpeaker(
-                            largeVideoState.oldResourceJid,
-                            false);
-                    }
+                // Change the way we'll be measuring and positioning large video
 
-                    // Enable new dominant speaker in the remote videos section.
-                    if (largeVideoState.userResourceJid) {
-                        VideoLayout.enableDominantSpeaker(
-                            largeVideoState.userResourceJid,
-                            true);
-                    }
+                VideoLayout.getVideoSize = largeVideoState.isDesktop
+                    ? getDesktopVideoSize
+                    : getCameraVideoSize;
+                VideoLayout.getVideoPosition = largeVideoState.isDesktop
+                    ? getDesktopVideoPosition
+                    : getCameraVideoPosition;
 
-                    if (userChanged && largeVideoState.isVisible) {
-                        // using "this" should be ok because we're called
-                        // from within the fadeOut event.
-                        $(this).fadeIn(300);
-                    }
 
-                    if(userChanged) {
-                        Avatar.showUserAvatar(
-                            APP.xmpp.findJidFromResource(
-                                largeVideoState.oldResourceJid));
-                    }
+                // Only if the large video is currently visible.
+                // Disable previous dominant speaker video.
+                if (largeVideoState.oldResourceJid) {
+                    VideoLayout.enableDominantSpeaker(
+                        largeVideoState.oldResourceJid,
+                        false);
+                }
 
-                    largeVideoState.updateInProgress = false;
-                };
+                // Enable new dominant speaker in the remote videos section.
+                if (largeVideoState.userResourceJid) {
+                    VideoLayout.enableDominantSpeaker(
+                        largeVideoState.userResourceJid,
+                        true);
+                }
 
-                if (userChanged) {
-                    $('#largeVideo').fadeOut(300, doUpdate);
-                } else {
-                    doUpdate();
+                if (largeVideoState.isVisible) {
+                    // using "this" should be ok because we're called
+                    // from within the fadeOut event.
+                    $(this).fadeIn(300);
                 }
-            }
+
+                Avatar.showUserAvatar(
+                    APP.xmpp.findJidFromResource(
+                        largeVideoState.oldResourceJid));
+            });
         } else {
             Avatar.showUserAvatar(
                 APP.xmpp.findJidFromResource(
             // If the container is currently visible we attach the stream.
             if (!isVideo
                 || (container.offsetParent !== null && isVideo)) {
-                var videoStream = APP.simulcast.getReceivingVideoStream(stream);
-                APP.RTC.attachMediaStream(sel, videoStream);
+                APP.RTC.attachMediaStream(sel, stream);
 
                 if (isVideo)
                     waitForRemoteVideo(sel, thessrc, stream, peerJid);
                     var mediaStream = APP.RTC.remoteStreams[jid][MediaStreamType.VIDEO_TYPE];
                     var sel = $('#participant_' + resourceJid + '>video');
 
-                    var videoStream = APP.simulcast.getReceivingVideoStream(
-                        mediaStream.stream);
-                    APP.RTC.attachMediaStream(sel, videoStream);
+                    APP.RTC.attachMediaStream(sel, mediaStream.stream);
                     if (lastNPickupJid == mediaStream.peerjid) {
                         // Clean up the lastN pickup jid.
                         lastNPickupJid = null;
         }
     };
 
-    my.onSimulcastLayersChanging = function (endpointSimulcastLayers) {
-        endpointSimulcastLayers.forEach(function (esl) {
-
-            var resource = esl.endpoint;
-
-            // if lastN is enabled *and* the endpoint is *not* in the lastN set,
-            // then ignore the event (= do not preload anything).
-            //
-            // The bridge could probably stop sending this message if it's for
-            // an endpoint that's not in lastN.
-
-            if (lastNCount != -1
-                && (lastNCount < 1 || lastNEndpointsCache.indexOf(resource) === -1)) {
-                return;
-            }
-
-            var primarySSRC = esl.simulcastLayer.primarySSRC;
-
-            // Get session and stream from primary ssrc.
-            var res = APP.simulcast.getReceivingVideoStreamBySSRC(primarySSRC);
-            var sid = res.sid;
-            var electedStream = res.stream;
-
-            if (sid && electedStream) {
-                var msid = APP.simulcast.getRemoteVideoStreamIdBySSRC(primarySSRC);
-
-                console.info([esl, primarySSRC, msid, sid, electedStream]);
-
-                var preload = (Strophe.getResourceFromJid(APP.xmpp.getJidFromSSRC(primarySSRC)) == largeVideoState.userResourceJid);
-
-                if (preload) {
-                    if (largeVideoState.preload)
-                    {
-                        $(largeVideoState.preload).remove();
-                    }
-                    console.info('Preloading remote video');
-                    largeVideoState.preload = $('<video autoplay></video>');
-                    // ssrcs are unique in an rtp session
-                    largeVideoState.preload_ssrc = primarySSRC;
-
-                    APP.RTC.attachMediaStream(largeVideoState.preload, electedStream)
-                }
-
-            } else {
-                console.error('Could not find a stream or a session.', sid, electedStream);
-            }
-        });
-    };
-
-    /**
-     * On simulcast layers changed event.
-     */
-    my.onSimulcastLayersChanged = function (endpointSimulcastLayers) {
-        endpointSimulcastLayers.forEach(function (esl) {
-
-            var resource = esl.endpoint;
-
-            // if lastN is enabled *and* the endpoint is *not* in the lastN set,
-            // then ignore the event (= do not change large video/thumbnail
-            // SRCs).
-            //
-            // Note that even if we ignore the "changed" event in this event
-            // handler, the bridge must continue sending these events because
-            // the simulcast code in simulcast.js uses it to know what's going
-            // to be streamed by the bridge when/if the endpoint gets back into
-            // the lastN set.
-
-            if (lastNCount != -1
-                && (lastNCount < 1 || lastNEndpointsCache.indexOf(resource) === -1)) {
-                return;
-            }
-
-            var primarySSRC = esl.simulcastLayer.primarySSRC;
-
-            // Get session and stream from primary ssrc.
-            var res = APP.simulcast.getReceivingVideoStreamBySSRC(primarySSRC);
-            var sid = res.sid;
-            var electedStream = res.stream;
-
-            if (sid && electedStream) {
-                var msid = APP.simulcast.getRemoteVideoStreamIdBySSRC(primarySSRC);
-
-                console.info('Switching simulcast substream.');
-                console.info([esl, primarySSRC, msid, sid, electedStream]);
-
-                var msidParts = msid.split(' ');
-                var selRemoteVideo = $(['#', 'remoteVideo_', sid, '_', msidParts[0]].join(''));
-
-                var updateLargeVideo = (Strophe.getResourceFromJid(APP.xmpp.getJidFromSSRC(primarySSRC))
-                    == largeVideoState.userResourceJid);
-                var updateFocusedVideoSrc = (focusedVideoInfo && focusedVideoInfo.src && focusedVideoInfo.src != '' &&
-                    (APP.RTC.getVideoSrc(selRemoteVideo[0]) == focusedVideoInfo.src));
-
-                var electedStreamUrl;
-                if (largeVideoState.preload_ssrc == primarySSRC)
-                {
-                    APP.RTC.setVideoSrc(selRemoteVideo[0], APP.RTC.getVideoSrc(largeVideoState.preload[0]));
-                }
-                else
-                {
-                    if (largeVideoState.preload
-                        && largeVideoState.preload != null) {
-                        $(largeVideoState.preload).remove();
-                    }
-
-                    largeVideoState.preload_ssrc = 0;
-
-                    APP.RTC.attachMediaStream(selRemoteVideo, electedStream);
-                }
-
-                var jid = APP.xmpp.getJidFromSSRC(primarySSRC);
-
-                if (updateLargeVideo) {
-                    VideoLayout.updateLargeVideo(APP.RTC.getVideoSrc(selRemoteVideo[0]), null,
-                        Strophe.getResourceFromJid(jid));
-                }
-
-                if (updateFocusedVideoSrc) {
-                    focusedVideoInfo.src = APP.RTC.getVideoSrc(selRemoteVideo[0]);
-                }
-
-                var videoId;
-                if(resource == APP.xmpp.myResource())
-                {
-                    videoId = "localVideoContainer";
-                }
-                else
-                {
-                    videoId = "participant_" + resource;
-                }
-                var connectionIndicator = VideoLayout.connectionIndicators[videoId];
-                if(connectionIndicator)
-                    connectionIndicator.updatePopoverData();
-
-            } else {
-                console.error('Could not find a stream or a sid.', sid, electedStream);
-            }
-        });
-    };
-
     /**
      * Updates local stats
      * @param percent

modules/simulcast/SimulcastLogger.js

-/**
- *
- * @constructor
- */
-function SimulcastLogger(name, lvl) {
-    this.name = name;
-    this.lvl = lvl;
-}
-
-SimulcastLogger.prototype.log = function (text) {
-    if (this.lvl) {
-        console.log(text);
-    }
-};
-
-SimulcastLogger.prototype.info = function (text) {
-    if (this.lvl > 1) {
-        console.info(text);
-    }
-};
-
-SimulcastLogger.prototype.fine = function (text) {
-    if (this.lvl > 2) {
-        console.log(text);
-    }
-};
-
-SimulcastLogger.prototype.error = function (text) {
-    console.error(text);
-};
-
-module.exports = SimulcastLogger;

modules/simulcast/SimulcastReceiver.js

-var SimulcastLogger = require("./SimulcastLogger");
-var SimulcastUtils = require("./SimulcastUtils");
-var MediaStreamType = require("../../service/RTC/MediaStreamTypes");
-
-function SimulcastReceiver() {
-    this.simulcastUtils = new SimulcastUtils();
-    this.logger = new SimulcastLogger('SimulcastReceiver', 1);
-}
-
-SimulcastReceiver.prototype._remoteVideoSourceCache = '';
-SimulcastReceiver.prototype._remoteMaps = {
-    msid2Quality: {},
-    ssrc2Msid: {},
-    msid2ssrc: {},
-    receivingVideoStreams: {}
-};
-
-SimulcastReceiver.prototype._cacheRemoteVideoSources = function (lines) {
-    this._remoteVideoSourceCache = this.simulcastUtils._getVideoSources(lines);
-};
-
-SimulcastReceiver.prototype._restoreRemoteVideoSources = function (lines) {
-    this.simulcastUtils._replaceVideoSources(lines, this._remoteVideoSourceCache);
-};
-
-SimulcastReceiver.prototype._ensureGoogConference = function (lines) {
-    var sb;
-
-    this.logger.info('Ensuring x-google-conference flag...')
-
-    if (this.simulcastUtils._indexOfArray('a=x-google-flag:conference', lines) === this.simulcastUtils._emptyCompoundIndex) {
-        // TODO(gp) do that for the audio as well as suggested by fippo.
-        // Add the google conference flag
-        sb = this.simulcastUtils._getVideoSources(lines);
-        sb = ['a=x-google-flag:conference'].concat(sb);
-        this.simulcastUtils._replaceVideoSources(lines, sb);
-    }
-};
-
-SimulcastReceiver.prototype._restoreSimulcastGroups = function (sb) {
-    this._restoreRemoteVideoSources(sb);
-};
-
-/**
- * Restores the simulcast groups of the remote description. In
- * transformRemoteDescription we remove those in order for the set remote
- * description to succeed. The focus needs the signal the groups to new
- * participants.
- *
- * @param desc
- * @returns {*}
- */
-SimulcastReceiver.prototype.reverseTransformRemoteDescription = function (desc) {
-    var sb;
-
-    if (!this.simulcastUtils.isValidDescription(desc)) {
-        return desc;
-    }
-
-    if (config.enableSimulcast) {
-        sb = desc.sdp.split('\r\n');
-
-        this._restoreSimulcastGroups(sb);
-
-        desc = new RTCSessionDescription({
-            type: desc.type,
-            sdp: sb.join('\r\n')
-        });
-    }
-
-    return desc;
-};
-
-SimulcastUtils.prototype._ensureOrder = function (lines) {
-    var videoSources, sb;
-
-    videoSources = this.parseMedia(lines, ['video'])[0];
-    sb = this._compileVideoSources(videoSources);
-
-    this._replaceVideoSources(lines, sb);
-};
-
-SimulcastReceiver.prototype._updateRemoteMaps = function (lines) {
-    var remoteVideoSources = this.simulcastUtils.parseMedia(lines, ['video'])[0],
-        videoSource, quality;
-
-    // (re) initialize the remote maps.
-    this._remoteMaps.msid2Quality = {};
-    this._remoteMaps.ssrc2Msid = {};
-    this._remoteMaps.msid2ssrc = {};
-
-    var self = this;
-    if (remoteVideoSources.groups && remoteVideoSources.groups.length !== 0) {
-        remoteVideoSources.groups.forEach(function (group) {
-            if (group.semantics === 'SIM' && group.ssrcs && group.ssrcs.length !== 0) {
-                quality = 0;
-                group.ssrcs.forEach(function (ssrc) {
-                    videoSource = remoteVideoSources.sources[ssrc];
-                    self._remoteMaps.msid2Quality[videoSource.msid] = quality++;
-                    self._remoteMaps.ssrc2Msid[videoSource.ssrc] = videoSource.msid;
-                    self._remoteMaps.msid2ssrc[videoSource.msid] = videoSource.ssrc;
-                });
-            }
-        });
-    }
-};
-
-SimulcastReceiver.prototype._setReceivingVideoStream = function (resource, ssrc) {
-    this._remoteMaps.receivingVideoStreams[resource] = ssrc;
-};
-
-/**
- * Returns a stream with single video track, the one currently being
- * received by this endpoint.
- *
- * @param stream the remote simulcast stream.
- * @returns {webkitMediaStream}
- */
-SimulcastReceiver.prototype.getReceivingVideoStream = function (stream) {
-    var tracks, i, electedTrack, msid, quality = 0, receivingTrackId;
-
-    var self = this;
-    if (config.enableSimulcast) {
-
-        stream.getVideoTracks().some(function (track) {
-            return Object.keys(self._remoteMaps.receivingVideoStreams).some(function (resource) {
-                var ssrc = self._remoteMaps.receivingVideoStreams[resource];
-                var msid = self._remoteMaps.ssrc2Msid[ssrc];
-                if (msid == [stream.id, track.id].join(' ')) {
-                    electedTrack = track;
-                    return true;
-                }
-            });
-        });
-
-        if (!electedTrack) {
-            // we don't have an elected track, choose by initial quality.
-            tracks = stream.getVideoTracks();
-            for (i = 0; i < tracks.length; i++) {
-                msid = [stream.id, tracks[i].id].join(' ');
-                if (this._remoteMaps.msid2Quality[msid] === quality) {
-                    electedTrack = tracks[i];
-                    break;
-                }
-            }
-
-            // TODO(gp) if the initialQuality could not be satisfied, lower
-            // the requirement and try again.
-        }
-    }
-
-    return (electedTrack)
-        ? new webkitMediaStream([electedTrack])
-        : stream;
-};
-
-SimulcastReceiver.prototype.getReceivingSSRC = function (jid) {
-    var resource = Strophe.getResourceFromJid(jid);
-    var ssrc = this._remoteMaps.receivingVideoStreams[resource];
-
-    // If we haven't receiving a "changed" event yet, then we must be receiving
-    // low quality (that the sender always streams).
-    if(!ssrc)
-    {
-        var remoteStreamObject = APP.RTC.remoteStreams[jid][MediaStreamType.VIDEO_TYPE];
-        var remoteStream = remoteStreamObject.getOriginalStream();
-        var tracks = remoteStream.getVideoTracks();
-        if (tracks) {
-            for (var k = 0; k < tracks.length; k++) {
-                var track = tracks[k];
-                var msid = [remoteStream.id, track.id].join(' ');
-                var _ssrc = this._remoteMaps.msid2ssrc[msid];
-                var quality = this._remoteMaps.msid2Quality[msid];
-                if (quality == 0) {
-                    ssrc = _ssrc;
-                }
-            }
-        }
-    }
-
-    return ssrc;
-};
-
-SimulcastReceiver.prototype.getReceivingVideoStreamBySSRC = function (ssrc)
-{
-    var sid, electedStream;
-    var i, j, k;
-    var jid = APP.xmpp.getJidFromSSRC(ssrc);
-    if(jid && APP.RTC.remoteStreams[jid])
-    {
-        var remoteStreamObject = APP.RTC.remoteStreams[jid][MediaStreamType.VIDEO_TYPE];
-        var remoteStream = remoteStreamObject.getOriginalStream();
-        var tracks = remoteStream.getVideoTracks();
-        if (tracks) {
-            for (k = 0; k < tracks.length; k++) {
-                var track = tracks[k];
-                var msid = [remoteStream.id, track.id].join(' ');
-                var tmp = this._remoteMaps.msid2ssrc[msid];
-                if (tmp == ssrc) {
-                    electedStream = new webkitMediaStream([track]);
-                    sid = remoteStreamObject.sid;
-                    // stream found, stop.
-                    break;
-                }
-            }
-        }
-
-    }
-    else
-    {
-        console.debug(APP.RTC.remoteStreams, jid, ssrc);
-    }
-
-    return {
-        sid: sid,
-        stream: electedStream
-    };
-};
-
-/**
- * Gets the fully qualified msid (stream.id + track.id) associated to the
- * SSRC.
- *
- * @param ssrc
- * @returns {*}
- */
-SimulcastReceiver.prototype.getRemoteVideoStreamIdBySSRC = function (ssrc) {
-    return this._remoteMaps.ssrc2Msid[ssrc];
-};
-
-/**
- * Removes the ssrc-group:SIM from the remote description bacause Chrome
- * either gets confused and thinks this is an FID group or, if an FID group
- * is already present, it fails to set the remote description.
- *
- * @param desc
- * @returns {*}
- */
-SimulcastReceiver.prototype.transformRemoteDescription = function (desc) {
-
-    if (desc && desc.sdp) {
-        var sb = desc.sdp.split('\r\n');
-
-        this._updateRemoteMaps(sb);
-        this._cacheRemoteVideoSources(sb);
-
-        // NOTE(gp) this needs to be called after updateRemoteMaps because we
-        // need the simulcast group in the _updateRemoteMaps() method.
-        this.simulcastUtils._removeSimulcastGroup(sb);
-
-        if (desc.sdp.indexOf('a=ssrc-group:SIM') !== -1) {
-            // We don't need the goog conference flag if we're not doing
-            // simulcast.
-            this._ensureGoogConference(sb);
-        }
-
-        desc = new RTCSessionDescription({
-            type: desc.type,
-            sdp: sb.join('\r\n')
-        });
-
-        this.logger.fine(['Transformed remote description', desc.sdp].join(' '));
-    }
-
-    return desc;
-};
-
-module.exports = SimulcastReceiver;

modules/simulcast/SimulcastSender.js

-var SimulcastLogger = require("./SimulcastLogger");
-var SimulcastUtils = require("./SimulcastUtils");
-
-function SimulcastSender() {
-    this.simulcastUtils = new SimulcastUtils();
-    this.logger = new SimulcastLogger('SimulcastSender', 1);
-}
-
-SimulcastSender.prototype.displayedLocalVideoStream = null;
-
-SimulcastSender.prototype._generateGuid = (function () {
-    function s4() {
-        return Math.floor((1 + Math.random()) * 0x10000)
-            .toString(16)
-            .substring(1);
-    }
-
-    return function () {
-        return s4() + s4() + '-' + s4() + '-' + s4() + '-' +
-            s4() + '-' + s4() + s4() + s4();
-    };
-}());
-
-// Returns a random integer between min (included) and max (excluded)
-// Using Math.round() gives a non-uniform distribution!
-SimulcastSender.prototype._generateRandomSSRC = function () {
-    var min = 0, max = 0xffffffff;
-    return Math.floor(Math.random() * (max - min)) + min;
-};
-
-SimulcastSender.prototype.getLocalVideoStream = function () {
-    return (this.displayedLocalVideoStream != null)
-        ? this.displayedLocalVideoStream
-        // in case we have no simulcast at all, i.e. we didn't perform the GUM
-        : APP.RTC.localVideo.getOriginalStream();
-};
-
-function NativeSimulcastSender() {
-    SimulcastSender.call(this); // call the super constructor.
-}
-
-NativeSimulcastSender.prototype = Object.create(SimulcastSender.prototype);
-
-NativeSimulcastSender.prototype._localExplosionMap = {};
-NativeSimulcastSender.prototype._isUsingScreenStream = false;
-NativeSimulcastSender.prototype._localVideoSourceCache = '';
-
-NativeSimulcastSender.prototype.reset = function () {
-    this._localExplosionMap = {};
-    this._isUsingScreenStream = APP.desktopsharing.isUsingScreenStream();
-};
-
-NativeSimulcastSender.prototype._cacheLocalVideoSources = function (lines) {
-    this._localVideoSourceCache = this.simulcastUtils._getVideoSources(lines);
-};
-
-NativeSimulcastSender.prototype._restoreLocalVideoSources = function (lines) {
-    this.simulcastUtils._replaceVideoSources(lines, this._localVideoSourceCache);
-};
-
-NativeSimulcastSender.prototype._appendSimulcastGroup = function (lines) {
-    var videoSources, ssrcGroup, simSSRC, numOfSubs = 2, i, sb, msid;
-
-    this.logger.info('Appending simulcast group...');
-
-    // Get the primary SSRC information.
-    videoSources = this.simulcastUtils.parseMedia(lines, ['video'])[0];
-
-    // Start building the SIM SSRC group.
-    ssrcGroup = ['a=ssrc-group:SIM'];
-
-    // The video source buffer.
-    sb = [];
-
-    // Create the simulcast sub-streams.
-    for (i = 0; i < numOfSubs; i++) {
-        // TODO(gp) prevent SSRC collision.
-        simSSRC = this._generateRandomSSRC();
-        ssrcGroup.push(simSSRC);
-
-        if (videoSources.base) {
-            sb.splice.apply(sb, [sb.length, 0].concat(
-                [["a=ssrc:", simSSRC, " cname:", videoSources.base.cname].join(''),
-                    ["a=ssrc:", simSSRC, " msid:", videoSources.base.msid].join('')]
-            ));
-        }
-
-        this.logger.info(['Generated substream ', i, ' with SSRC ', simSSRC, '.'].join(''));
-
-    }
-
-    // Add the group sim layers.
-    sb.splice(0, 0, ssrcGroup.join(' '))
-
-    this.simulcastUtils._replaceVideoSources(lines, sb);
-};
-
-// Does the actual patching.
-NativeSimulcastSender.prototype._ensureSimulcastGroup = function (lines) {
-
-    this.logger.info('Ensuring simulcast group...');
-
-    if (this.simulcastUtils._indexOfArray('a=ssrc-group:SIM', lines) === this.simulcastUtils._emptyCompoundIndex) {
-        this._appendSimulcastGroup(lines);
-        this._cacheLocalVideoSources(lines);
-    } else {
-        // verify that the ssrcs participating in the SIM group are present
-        // in the SDP (needed for presence).
-        this._restoreLocalVideoSources(lines);
-    }
-};
-
-/**
- * Produces a single stream with multiple tracks for local video sources.
- *
- * @param lines
- * @private
- */
-NativeSimulcastSender.prototype._explodeSimulcastSenderSources = function (lines) {
-    var sb, msid, sid, tid, videoSources, self;
-
-    this.logger.info('Exploding local video sources...');
-
-    videoSources = this.simulcastUtils.parseMedia(lines, ['video'])[0];
-
-    self = this;
-    if (videoSources.groups && videoSources.groups.length !== 0) {
-        videoSources.groups.forEach(function (group) {
-            if (group.semantics === 'SIM') {
-                group.ssrcs.forEach(function (ssrc) {
-
-                    // Get the msid for this ssrc..
-                    if (self._localExplosionMap[ssrc]) {
-                        // .. either from the explosion map..
-                        msid = self._localExplosionMap[ssrc];
-                    } else {
-                        // .. or generate a new one (msid).
-                        sid = videoSources.sources[ssrc].msid
-                            .substring(0, videoSources.sources[ssrc].msid.indexOf(' '));
-
-                        tid = self._generateGuid();
-                        msid = [sid, tid].join(' ');
-                        self._localExplosionMap[ssrc] = msid;
-                    }
-
-                    // Assign it to the source object.
-                    videoSources.sources[ssrc].msid = msid;
-
-                    // TODO(gp) Change the msid of associated sources.
-                });
-            }
-        });
-    }
-
-    sb = this.simulcastUtils._compileVideoSources(videoSources);
-
-    this.simulcastUtils._replaceVideoSources(lines, sb);
-};
-
-/**
- * GUM for simulcast.
- *
- * @param constraints
- * @param success
- * @param err
- */
-NativeSimulcastSender.prototype.getUserMedia = function (constraints, success, err) {
-
-    // There's nothing special to do for native simulcast, so just do a normal GUM.
-    navigator.webkitGetUserMedia(constraints, function (hqStream) {
-        success(hqStream);
-    }, err);
-};
-
-/**
- * Prepares the local description for public usage (i.e. to be signaled
- * through Jingle to the focus).
- *
- * @param desc
- * @returns {RTCSessionDescription}
- */
-NativeSimulcastSender.prototype.reverseTransformLocalDescription = function (desc) {
-    var sb;
-
-    if (!this.simulcastUtils.isValidDescription(desc) || this._isUsingScreenStream) {
-        return desc;
-    }
-
-
-    sb = desc.sdp.split('\r\n');
-
-    this._explodeSimulcastSenderSources(sb);
-
-    desc = new RTCSessionDescription({
-        type: desc.type,
-        sdp: sb.join('\r\n')
-    });
-
-    this.logger.fine(['Exploded local video sources', desc.sdp].join(' '));
-
-    return desc;
-};
-
-/**
- * Ensures that the simulcast group is present in the answer, _if_ native
- * simulcast is enabled,
- *
- * @param desc
- * @returns {*}
- */
-NativeSimulcastSender.prototype.transformAnswer = function (desc) {
-
-    if (!this.simulcastUtils.isValidDescription(desc) || this._isUsingScreenStream) {
-        return desc;
-    }
-
-    var sb = desc.sdp.split('\r\n');
-
-    // Even if we have enabled native simulcasting previously
-    // (with a call to SLD with an appropriate SDP, for example),
-    // createAnswer seems to consistently generate incomplete SDP
-    // with missing SSRCS.
-    //
-    // So, subsequent calls to SLD will have missing SSRCS and presence
-    // won't have the complete list of SRCs.
-    this._ensureSimulcastGroup(sb);
-
-    desc = new RTCSessionDescription({
-        type: desc.type,
-        sdp: sb.join('\r\n')
-    });
-
-    this.logger.fine(['Transformed answer', desc.sdp].join(' '));
-
-    return desc;
-};
-
-
-/**
- *
- *
- * @param desc
- * @returns {*}
- */
-NativeSimulcastSender.prototype.transformLocalDescription = function (desc) {
-    return desc;
-};
-
-NativeSimulcastSender.prototype._setLocalVideoStreamEnabled = function (ssrc, enabled) {
-    // Nothing to do here, native simulcast does that auto-magically.
-};
-
-NativeSimulcastSender.prototype.constructor = NativeSimulcastSender;
-
-function SimpleSimulcastSender() {
-    SimulcastSender.call(this);
-}
-
-SimpleSimulcastSender.prototype = Object.create(SimulcastSender.prototype);
-
-SimpleSimulcastSender.prototype.localStream = null;
-SimpleSimulcastSender.prototype._localMaps = {
-    msids: [],
-    msid2ssrc: {}
-};
-
-/**
- * Groups local video sources together in the ssrc-group:SIM group.
- *
- * @param lines
- * @private
- */
-SimpleSimulcastSender.prototype._groupLocalVideoSources = function (lines) {
-    var sb, videoSources, ssrcs = [], ssrc;
-
-    this.logger.info('Grouping local video sources...');
-
-    videoSources = this.simulcastUtils.parseMedia(lines, ['video'])[0];
-
-    for (ssrc in videoSources.sources) {
-        // jitsi-meet destroys/creates streams at various places causing
-        // the original local stream ids to change. The only thing that
-        // remains unchanged is the trackid.
-        this._localMaps.msid2ssrc[videoSources.sources[ssrc].msid.split(' ')[1]] = ssrc;
-    }
-
-    var self = this;
-    // TODO(gp) add only "free" sources.
-    this._localMaps.msids.forEach(function (msid) {
-        ssrcs.push(self._localMaps.msid2ssrc[msid]);
-    });
-
-    if (!videoSources.groups) {
-        videoSources.groups = [];
-    }
-
-    videoSources.groups.push({
-        'semantics': 'SIM',
-        'ssrcs': ssrcs
-    });
-
-    sb = this.simulcastUtils._compileVideoSources(videoSources);
-
-    this.simulcastUtils._replaceVideoSources(lines, sb);
-};
-
-/**
- * GUM for simulcast.
- *
- * @param constraints
- * @param success
- * @param err
- */
-SimpleSimulcastSender.prototype.getUserMedia = function (constraints, success, err) {
-
-    // TODO(gp) what if we request a resolution not supported by the hardware?
-    // TODO(gp) make the lq stream configurable; although this wouldn't work with native simulcast
-    var lqConstraints = {
-        audio: false,
-        video: {
-            mandatory: {
-                maxWidth: 320,
-                maxHeight: 180,
-                maxFrameRate: 15
-            }
-        }
-    };
-
-    this.logger.info('HQ constraints: ', constraints);
-    this.logger.info('LQ constraints: ', lqConstraints);
-
-
-    // NOTE(gp) if we request the lq stream first webkitGetUserMedia
-    // fails randomly. Tested with Chrome 37. As fippo suggested, the
-    // reason appears to be that Chrome only acquires the cam once and
-    // then downscales the picture (https://code.google.com/p/chromium/issues/detail?id=346616#c11)
-
-    var self = this;
-    navigator.webkitGetUserMedia(constraints, function (hqStream) {
-
-        self.localStream = hqStream;
-
-        // reset local maps.
-        self._localMaps.msids = [];
-        self._localMaps.msid2ssrc = {};
-
-        // add hq trackid to local map
-        self._localMaps.msids.push(hqStream.getVideoTracks()[0].id);
-
-        navigator.webkitGetUserMedia(lqConstraints, function (lqStream) {
-
-            self.displayedLocalVideoStream = lqStream;
-
-            // NOTE(gp) The specification says Array.forEach() will visit
-            // the array elements in numeric order, and that it doesn't
-            // visit elements that don't exist.
-
-            // add lq trackid to local map
-            self._localMaps.msids.splice(0, 0, lqStream.getVideoTracks()[0].id);
-
-            self.localStream.addTrack(lqStream.getVideoTracks()[0]);
-            success(self.localStream);
-        }, err);
-    }, err);
-};
-
-/**
- * Prepares the local description for public usage (i.e. to be signaled
- * through Jingle to the focus).
- *
- * @param desc
- * @returns {RTCSessionDescription}
- */
-SimpleSimulcastSender.prototype.reverseTransformLocalDescription = function (desc) {
-    var sb;
-
-    if (!this.simulcastUtils.isValidDescription(desc)) {
-        return desc;
-    }
-
-    sb = desc.sdp.split('\r\n');
-
-    this._groupLocalVideoSources(sb);
-
-    desc = new RTCSessionDescription({
-        type: desc.type,
-        sdp: sb.join('\r\n')
-    });
-
-    this.logger.fine('Grouped local video sources');
-    this.logger.fine(desc.sdp);
-
-    return desc;
-};
-
-/**
- * Ensures that the simulcast group is present in the answer, _if_ native
- * simulcast is enabled,
- *
- * @param desc
- * @returns {*}
- */
-SimpleSimulcastSender.prototype.transformAnswer = function (desc) {
-    return desc;
-};
-
-
-/**
- *
- *
- * @param desc
- * @returns {*}
- */
-SimpleSimulcastSender.prototype.transformLocalDescription = function (desc) {
-
-    var sb = desc.sdp.split('\r\n');
-
-    this.simulcastUtils._removeSimulcastGroup(sb);
-
-    desc = new RTCSessionDescription({
-        type: desc.type,
-        sdp: sb.join('\r\n')
-    });
-
-    this.logger.fine('Transformed local description');
-    this.logger.fine(desc.sdp);
-
-    return desc;
-};
-
-SimpleSimulcastSender.prototype._setLocalVideoStreamEnabled = function (ssrc, enabled) {
-    var trackid;
-
-    var self = this;
-    this.logger.log(['Requested to', enabled ? 'enable' : 'disable', ssrc].join(' '));
-    if (Object.keys(this._localMaps.msid2ssrc).some(function (tid) {
-        // Search for the track id that corresponds to the ssrc
-        if (self._localMaps.msid2ssrc[tid] == ssrc) {
-            trackid = tid;
-            return true;
-        }
-    }) && self.localStream.getVideoTracks().some(function (track) {
-        // Start/stop the track that corresponds to the track id
-        if (track.id === trackid) {
-            track.enabled = enabled;
-            return true;
-        }
-    })) {
-        this.logger.log([trackid, enabled ? 'enabled' : 'disabled'].join(' '));
-        $(document).trigger(enabled
-            ? 'simulcastlayerstarted'
-            : 'simulcastlayerstopped');
-    } else {
-        this.logger.error("I don't have a local stream with SSRC " + ssrc);
-    }
-};
-
-SimpleSimulcastSender.prototype.constructor = SimpleSimulcastSender;
-
-function NoSimulcastSender() {
-    SimulcastSender.call(this);
-}
-
-NoSimulcastSender.prototype = Object.create(SimulcastSender.prototype);
-
-/**
- * GUM for simulcast.
- *
- * @param constraints
- * @param success
- * @param err
- */
-NoSimulcastSender.prototype.getUserMedia = function (constraints, success, err) {
-    navigator.webkitGetUserMedia(constraints, function (hqStream) {
-        success(hqStream);
-    }, err);
-};
-
-/**
- * Prepares the local description for public usage (i.e. to be signaled
- * through Jingle to the focus).
- *
- * @param desc
- * @returns {RTCSessionDescription}
- */
-NoSimulcastSender.prototype.reverseTransformLocalDescription = function (desc) {
-    return desc;
-};
-
-/**
- * Ensures that the simulcast group is present in the answer, _if_ native
- * simulcast is enabled,
- *
- * @param desc
- * @returns {*}
- */
-NoSimulcastSender.prototype.transformAnswer = function (desc) {
-    return desc;
-};
-
-
-/**
- *
- *
- * @param desc
- * @returns {*}
- */
-NoSimulcastSender.prototype.transformLocalDescription = function (desc) {
-    return desc;
-};
-
-NoSimulcastSender.prototype._setLocalVideoStreamEnabled = function (ssrc, enabled) {
-
-};
-
-NoSimulcastSender.prototype.constructor = NoSimulcastSender;
-
-module.exports = {
-    "native": NativeSimulcastSender,
-    "no": NoSimulcastSender
-}

modules/simulcast/SimulcastUtils.js

-var SimulcastLogger = require("./SimulcastLogger");
-
-/**
- *
- * @constructor
- */
-function SimulcastUtils() {
-    this.logger = new SimulcastLogger("SimulcastUtils", 1);
-}
-
-/**
- *
- * @type {{}}
- * @private
- */
-SimulcastUtils.prototype._emptyCompoundIndex = {};
-
-/**
- *
- * @param lines
- * @param videoSources
- * @private
- */
-SimulcastUtils.prototype._replaceVideoSources = function (lines, videoSources) {
-    var i, inVideo = false, index = -1, howMany = 0;
-
-    this.logger.info('Replacing video sources...');
-
-    for (i = 0; i < lines.length; i++) {
-        if (inVideo && lines[i].substring(0, 'm='.length) === 'm=') {
-            // Out of video.
-            break;
-        }
-
-        if (!inVideo && lines[i].substring(0, 'm=video '.length) === 'm=video ') {
-            // In video.
-            inVideo = true;
-        }
-
-        if (inVideo && (lines[i].substring(0, 'a=ssrc:'.length) === 'a=ssrc:'
-            || lines[i].substring(0, 'a=ssrc-group:'.length) === 'a=ssrc-group:')) {
-
-            if (index === -1) {
-                index = i;
-            }
-
-            howMany++;
-        }
-    }
-
-    //  efficiency baby ;)
-    lines.splice.apply(lines,
-        [index, howMany].concat(videoSources));
-
-};
-
-SimulcastUtils.prototype.isValidDescription = function (desc)
-{
-    return desc && desc != null
-        && desc.type && desc.type != ''
-        && desc.sdp && desc.sdp != '';
-};
-
-SimulcastUtils.prototype._getVideoSources = function (lines) {
-    var i, inVideo = false, sb = [];
-
-    this.logger.info('Getting video sources...');
-
-    for (i = 0; i < lines.length; i++) {
-        if (inVideo && lines[i].substring(0, 'm='.length) === 'm=') {
-            // Out of video.
-            break;
-        }
-
-        if (!inVideo && lines[i].substring(0, 'm=video '.length) === 'm=video ') {
-            // In video.
-            inVideo = true;
-        }
-
-        if (inVideo && lines[i].substring(0, 'a=ssrc:'.length) === 'a=ssrc:') {
-            // In SSRC.
-            sb.push(lines[i]);
-        }
-
-        if (inVideo && lines[i].substring(0, 'a=ssrc-group:'.length) === 'a=ssrc-group:') {
-            sb.push(lines[i]);
-        }
-    }
-
-    return sb;
-};
-
-SimulcastUtils.prototype.parseMedia = function (lines, mediatypes) {
-    var i, res = [], type, cur_media, idx, ssrcs, cur_ssrc, ssrc,
-        ssrc_attribute, group, semantics, skip = true;
-
-    this.logger.info('Parsing media sources...');
-
-    for (i = 0; i < lines.length; i++) {
-        if (lines[i].substring(0, 'm='.length) === 'm=') {
-
-            type = lines[i]
-                .substr('m='.length, lines[i].indexOf(' ') - 'm='.length);
-            skip = mediatypes !== undefined && mediatypes.indexOf(type) === -1;
-
-            if (!skip) {
-                cur_media = {
-                    'type': type,
-                    'sources': {},
-                    'groups': []
-                };
-
-                res.push(cur_media);
-            }
-
-        } else if (!skip && lines[i].substring(0, 'a=ssrc:'.length) === 'a=ssrc:') {
-
-            idx = lines[i].indexOf(' ');
-            ssrc = lines[i].substring('a=ssrc:'.length, idx);
-            if (cur_media.sources[ssrc] === undefined) {
-                cur_ssrc = {'ssrc': ssrc};
-                cur_media.sources[ssrc] = cur_ssrc;
-            }
-
-            ssrc_attribute = lines[i].substr(idx + 1).split(':', 2)[0];
-            cur_ssrc[ssrc_attribute] = lines[i].substr(idx + 1).split(':', 2)[1];
-
-            if (cur_media.base === undefined) {
-                cur_media.base = cur_ssrc;
-            }
-
-        } else if (!skip && lines[i].substring(0, 'a=ssrc-group:'.length) === 'a=ssrc-group:') {
-            idx = lines[i].indexOf(' ');
-            semantics = lines[i].substr(0, idx).substr('a=ssrc-group:'.length);
-            ssrcs = lines[i].substr(idx).trim().split(' ');
-            group = {
-                'semantics': semantics,
-                'ssrcs': ssrcs
-            };
-            cur_media.groups.push(group);
-        } else if (!skip && (lines[i].substring(0, 'a=sendrecv'.length) === 'a=sendrecv' ||
-            lines[i].substring(0, 'a=recvonly'.length) === 'a=recvonly' ||
-            lines[i].substring(0, 'a=sendonly'.length) === 'a=sendonly' ||
-            lines[i].substring(0, 'a=inactive'.length) === 'a=inactive')) {
-
-            cur_media.direction = lines[i].substring('a='.length);
-        }
-    }
-
-    return res;
-};
-
-/**
- * The _indexOfArray() method returns the first a CompoundIndex at which a
- * given element can be found in the array, or _emptyCompoundIndex if it is
- * not present.
- *
- * Example:
- *
- * _indexOfArray('3', [ 'this is line 1', 'this is line 2', 'this is line 3' ])
- *
- * returns {row: 2, column: 14}
- *
- * @param needle
- * @param haystack
- * @param start
- * @returns {}
- * @private
- */
-SimulcastUtils.prototype._indexOfArray = function (needle, haystack, start) {
-    var length = haystack.length, idx, i;
-
-    if (!start) {
-        start = 0;
-    }
-
-    for (i = start; i < length; i++) {
-        idx = haystack[i].indexOf(needle);
-        if (idx !== -1) {
-            return {row: i, column: idx};
-        }
-    }
-    return this._emptyCompoundIndex;
-};
-
-SimulcastUtils.prototype._removeSimulcastGroup = function (lines) {
-    var i;
-
-    for (i = lines.length - 1; i >= 0; i--) {
-        if (lines[i].indexOf('a=ssrc-group:SIM') !== -1) {
-            lines.splice(i, 1);
-        }
-    }
-};
-
-SimulcastUtils.prototype._compileVideoSources = function (videoSources) {
-    var sb = [], ssrc, addedSSRCs = [];
-
-    this.logger.info('Compiling video sources...');
-
-    // Add the groups
-    if (videoSources.groups && videoSources.groups.length !== 0) {
-        videoSources.groups.forEach(function (group) {
-            if (group.ssrcs && group.ssrcs.length !== 0) {
-                sb.push([['a=ssrc-group:', group.semantics].join(''), group.ssrcs.join(' ')].join(' '));
-
-                // if (group.semantics !== 'SIM') {
-                group.ssrcs.forEach(function (ssrc) {
-                    addedSSRCs.push(ssrc);
-                    sb.splice.apply(sb, [sb.length, 0].concat([
-                        ["a=ssrc:", ssrc, " cname:", videoSources.sources[ssrc].cname].join(''),
-                        ["a=ssrc:", ssrc, " msid:", videoSources.sources[ssrc].msid].join('')]));
-                });
-                //}
-            }
-        });
-    }
-
-    // Then add any free sources.
-    if (videoSources.sources) {
-        for (ssrc in videoSources.sources) {
-            if (addedSSRCs.indexOf(ssrc) === -1) {
-                sb.splice.apply(sb, [sb.length, 0].concat([
-                    ["a=ssrc:", ssrc, " cname:", videoSources.sources[ssrc].cname].join(''),
-                    ["a=ssrc:", ssrc, " msid:", videoSources.sources[ssrc].msid].join('')]));
-            }
-        }
-    }
-
-    return sb;
-};
-
-module.exports = SimulcastUtils;

modules/simulcast/simulcast.js

-/*jslint plusplus: true */
-/*jslint nomen: true*/
-
-var SimulcastSender = require("./SimulcastSender");
-var NoSimulcastSender = SimulcastSender["no"];
-var NativeSimulcastSender = SimulcastSender["native"];
-var SimulcastReceiver = require("./SimulcastReceiver");
-var SimulcastUtils = require("./SimulcastUtils");
-var RTCEvents = require("../../service/RTC/RTCEvents");
-
-
-/**
- *
- * @constructor
- */
-function SimulcastManager() {
-
-    // Create the simulcast utilities.
-    this.simulcastUtils = new SimulcastUtils();
-
-    // Create remote simulcast.
-    this.simulcastReceiver = new SimulcastReceiver();
-
-    // Initialize local simulcast.
-
-    // TODO(gp) move into SimulcastManager.prototype.getUserMedia and take into
-    // account constraints.
-    if (!config.enableSimulcast) {
-        this.simulcastSender = new NoSimulcastSender();
-    } else {
-
-        var isChromium = window.chrome,
-            vendorName = window.navigator.vendor;
-        if(isChromium !== null && isChromium !== undefined
-            /* skip opera */
-            && vendorName === "Google Inc."
-            /* skip Chromium as suggested by fippo */
-            && !window.navigator.appVersion.match(/Chromium\//) ) {
-            var ver = parseInt(window.navigator.appVersion.match(/Chrome\/(\d+)\./)[1], 10);
-            if (ver > 37) {
-                this.simulcastSender = new NativeSimulcastSender();
-            } else {
-                this.simulcastSender = new NoSimulcastSender();
-            }
-        } else {
-            this.simulcastSender = new NoSimulcastSender();
-        }
-
-    }
-    APP.RTC.addListener(RTCEvents.SIMULCAST_LAYER_CHANGED,
-        function (endpointSimulcastLayers) {
-            endpointSimulcastLayers.forEach(function (esl) {
-                var ssrc = esl.simulcastLayer.primarySSRC;
-                simulcast._setReceivingVideoStream(esl.endpoint, ssrc);
-            });
-        });
-    APP.RTC.addListener(RTCEvents.SIMULCAST_START, function (simulcastLayer) {
-        var ssrc = simulcastLayer.primarySSRC;
-        simulcast._setLocalVideoStreamEnabled(ssrc, true);
-    });
-    APP.RTC.addListener(RTCEvents.SIMULCAST_STOP, function (simulcastLayer) {
-        var ssrc = simulcastLayer.primarySSRC;
-        simulcast._setLocalVideoStreamEnabled(ssrc, false);
-    });
-
-}
-
-/**
- * Restores the simulcast groups of the remote description. In
- * transformRemoteDescription we remove those in order for the set remote
- * description to succeed. The focus needs the signal the groups to new
- * participants.
- *
- * @param desc
- * @returns {*}
- */
-SimulcastManager.prototype.reverseTransformRemoteDescription = function (desc) {
-    return this.simulcastReceiver.reverseTransformRemoteDescription(desc);
-};
-
-/**
- * Removes the ssrc-group:SIM from the remote description bacause Chrome
- * either gets confused and thinks this is an FID group or, if an FID group
- * is already present, it fails to set the remote description.
- *
- * @param desc
- * @returns {*}
- */
-SimulcastManager.prototype.transformRemoteDescription = function (desc) {
-    return this.simulcastReceiver.transformRemoteDescription(desc);
-};
-
-/**
- * Gets the fully qualified msid (stream.id + track.id) associated to the
- * SSRC.
- *
- * @param ssrc
- * @returns {*}
- */
-SimulcastManager.prototype.getRemoteVideoStreamIdBySSRC = function (ssrc) {
-    return this.simulcastReceiver.getRemoteVideoStreamIdBySSRC(ssrc);
-};
-
-/**
- * Returns a stream with single video track, the one currently being
- * received by this endpoint.
- *
- * @param stream the remote simulcast stream.
- * @returns {webkitMediaStream}
- */
-SimulcastManager.prototype.getReceivingVideoStream = function (stream) {
-    return this.simulcastReceiver.getReceivingVideoStream(stream);
-};
-
-/**
- *
- *
- * @param desc
- * @returns {*}
- */
-SimulcastManager.prototype.transformLocalDescription = function (desc) {
-    return this.simulcastSender.transformLocalDescription(desc);
-};
-
-/**
- *
- * @returns {*}
- */
-SimulcastManager.prototype.getLocalVideoStream = function() {
-    return this.simulcastSender.getLocalVideoStream();
-};
-
-/**
- * GUM for simulcast.
- *
- * @param constraints
- * @param success
- * @param err
- */
-SimulcastManager.prototype.getUserMedia = function (constraints, success, err) {
-
-    this.simulcastSender.getUserMedia(constraints, success, err);
-};
-
-/**
- * Prepares the local description for public usage (i.e. to be signaled
- * through Jingle to the focus).
- *
- * @param desc
- * @returns {RTCSessionDescription}
- */
-SimulcastManager.prototype.reverseTransformLocalDescription = function (desc) {
-    return this.simulcastSender.reverseTransformLocalDescription(desc);
-};
-
-/**
- * Ensures that the simulcast group is present in the answer, _if_ native
- * simulcast is enabled,
- *
- * @param desc
- * @returns {*}
- */
-SimulcastManager.prototype.transformAnswer = function (desc) {
-    return this.simulcastSender.transformAnswer(desc);
-};
-
-SimulcastManager.prototype.getReceivingSSRC = function (jid) {
-    return this.simulcastReceiver.getReceivingSSRC(jid);
-};
-
-SimulcastManager.prototype.getReceivingVideoStreamBySSRC = function (msid) {
-    return this.simulcastReceiver.getReceivingVideoStreamBySSRC(msid);
-};
-
-/**
- *
- * @param lines
- * @param mediatypes
- * @returns {*}
- */
-SimulcastManager.prototype.parseMedia = function(lines, mediatypes) {
-    var sb = lines.sdp.split('\r\n');
-    return this.simulcastUtils.parseMedia(sb, mediatypes);
-};
-
-SimulcastManager.prototype._setReceivingVideoStream = function(resource, ssrc) {
-    this.simulcastReceiver._setReceivingVideoStream(resource, ssrc);
-};
-
-SimulcastManager.prototype._setLocalVideoStreamEnabled = function(ssrc, enabled) {
-    this.simulcastSender._setLocalVideoStreamEnabled(ssrc, enabled);
-};
-
-SimulcastManager.prototype.resetSender = function() {
-    if (typeof this.simulcastSender.reset === 'function'){
-        this.simulcastSender.reset();
-    }
-};
-
-var simulcast = new SimulcastManager();
-
-module.exports = simulcast;

modules/transform/transform.js

-var transform = require('sdp-transform');
-
-exports.write = function(session, opts) {
-
-    if (typeof session !== 'undefined' &&
-        typeof session.media !== 'undefined' &&
-        Array.isArray(session.media)) {
-
-        session.media.forEach(function (mLine) {
-            // expand sources to ssrcs
-            if (typeof mLine.sources !== 'undefined' &&
-                Object.keys(mLine.sources).length !== 0) {
-                mLine.ssrcs = [];
-                Object.keys(mLine.sources).forEach(function (ssrc) {
-                    var source = mLine.sources[ssrc];
-                    Object.keys(source).forEach(function (attribute) {
-                        mLine.ssrcs.push({
-                            id: ssrc,
-                            attribute: attribute,
-                            value: source[attribute]
-                        });
-                    });
-                });
-                delete mLine.sources;
-            }
-
-            // join ssrcs in ssrc groups
-            if (typeof mLine.ssrcGroups !== 'undefined' &&
-                Array.isArray(mLine.ssrcGroups)) {
-                mLine.ssrcGroups.forEach(function (ssrcGroup) {
-                    if (typeof ssrcGroup.ssrcs !== 'undefined' &&
-                        Array.isArray(ssrcGroup.ssrcs)) {
-                        ssrcGroup.ssrcs = ssrcGroup.ssrcs.join(' ');
-                    }
-                });
-            }
-        });
-    }
-
-    // join group mids
-    if (typeof session !== 'undefined' &&
-        typeof session.groups !== 'undefined' && Array.isArray(session.groups)) {
-
-        session.groups.forEach(function (g) {
-            if (typeof g.mids !== 'undefined' && Array.isArray(g.mids)) {
-                g.mids = g.mids.join(' ');
-            }
-        });
-    }
-
-    return transform.write(session, opts);
-};
-
-exports.parse = function(sdp) {
-    var session = transform.parse(sdp);
-
-    if (typeof session !== 'undefined' && typeof session.media !== 'undefined' &&
-        Array.isArray(session.media)) {
-
-        session.media.forEach(function (mLine) {
-            // group sources attributes by ssrc
-            if (typeof mLine.ssrcs !== 'undefined' && Array.isArray(mLine.ssrcs)) {
-                mLine.sources = {};
-                mLine.ssrcs.forEach(function (ssrc) {
-                    if (!mLine.sources[ssrc.id])
-                        mLine.sources[ssrc.id] = {};
-                    mLine.sources[ssrc.id][ssrc.attribute] = ssrc.value;
-                });
-
-                delete mLine.ssrcs;
-            }
-
-            // split ssrcs in ssrc groups
-            if (typeof mLine.ssrcGroups !== 'undefined' &&
-                Array.isArray(mLine.ssrcGroups)) {
-                mLine.ssrcGroups.forEach(function (ssrcGroup) {
-                    if (typeof ssrcGroup.ssrcs === 'string') {
-                        ssrcGroup.ssrcs = ssrcGroup.ssrcs.split(' ');
-                    }
-                });
-            }
-        });
-    }
-    // split group mids
-    if (typeof session !== 'undefined' &&
-        typeof session.groups !== 'undefined' && Array.isArray(session.groups)) {
-
-        session.groups.forEach(function (g) {
-            if (typeof g.mids === 'string') {
-                g.mids = g.mids.split(' ');
-            }
-        });
-    }
-
-    return session;
-};
-

modules/xmpp/JingleSession.js

 var SDP = require("./SDP");
 var RTCBrowserType = require("../../service/RTC/RTCBrowserType");
 var async = require("async");
+var transform = require("sdp-transform");
 
 // Jingle stuff
 function JingleSession(me, sid, connection, service) {
     };
     this.peerconnection.onaddstream = function (event) {
         if (event.stream.id !== 'default') {
-            console.log("REMOTE STREAM ADDED: " + event.stream + " - " + event.stream.id);
-            self.remoteStreamAdded(event);
+        console.log("REMOTE STREAM ADDED: " + event.stream + " - " + event.stream.id);
+        self.remoteStreamAdded(event);
         } else {
             // This is a recvonly stream. Clients that implement Unified Plan,
             // such as Firefox use recvonly "streams/channels/tracks" for
         // FIXME: change any inactive to sendrecv or whatever they were originally
         pranswer.sdp = pranswer.sdp.replace('a=inactive', 'a=sendrecv');
     }
-    pranswer = APP.simulcast.reverseTransformLocalDescription(pranswer);
     var prsdp = new SDP(pranswer.sdp);
     var accept = $iq({to: this.peerjid,
         type: 'set'})
                         initiator: self.initiator,
                         responder: self.responder,
                         sid: self.sid });
-                var publicLocalDesc = APP.simulcast.reverseTransformLocalDescription(sdp);
-                var publicLocalSDP = new SDP(publicLocalDesc.sdp);
-                publicLocalSDP.toJingle(accept, self.initiator == self.me ? 'initiator' : 'responder', ssrcs);
+                self.localSDP.toJingle(accept, self.initiator == self.me ? 'initiator' : 'responder', ssrcs);
                 self.connection.sendIQ(accept,
                     function () {
                         var ack = {};
     }
 
     if(!isAudio)
-        APP.RTC.switchVideoStreams(new_stream, oldStream);
+    APP.RTC.switchVideoStreams(new_stream, oldStream);
 
     // Conference is not active
     if(!oldSdp || !self.peerconnection) {
 JingleSession.prototype.setLocalDescription = function () {
     // put our ssrcs into presence so other clients can identify our stream
     var newssrcs = [];
-    var media = APP.simulcast.parseMedia(this.peerconnection.localDescription);
-    media.forEach(function (media) {
+    var session = transform.parse(this.peerconnection.localDescription.sdp);
+    session.media.forEach(function (media) {
 
-        if(Object.keys(media.sources).length > 0) {
+        if (media.ssrcs != null && media.ssrcs.length > 0) {
             // TODO(gp) maybe exclude FID streams?
-            Object.keys(media.sources).forEach(function (ssrc) {
+            media.ssrcs.forEach(function (ssrc) {
+                if (ssrc.attribute !== 'cname') {
+                    return;
+                }
                 newssrcs.push({
-                    'ssrc': ssrc,
+                    'ssrc': ssrc.id,
                     'type': media.type,
                     'direction': media.direction
                 });

modules/xmpp/TraceablePeerConnection.js

     this.maxstats = 0; // limit to 300 values, i.e. 5 minutes; set to 0 to disable
     var Interop = require('sdp-interop').Interop;
     this.interop = new Interop();
+    var Simulcast = require('sdp-simulcast');
+    this.simulcast = new Simulcast({numOfLayers: 3, explodeRemoteSimulcast: false});
 
     // override as desired
     this.trace = function (what, info) {
     TraceablePeerConnection.prototype.__defineGetter__('signalingState', function() { return this.peerconnection.signalingState; });
     TraceablePeerConnection.prototype.__defineGetter__('iceConnectionState', function() { return this.peerconnection.iceConnectionState; });
     TraceablePeerConnection.prototype.__defineGetter__('localDescription', function() {
-        this.trace('getLocalDescription::preTransform (Plan A)', dumpSDP(this.peerconnection.localDescription));
-        // if we're running on FF, transform to Plan B first.
         var desc = this.peerconnection.localDescription;
+        this.trace('getLocalDescription::preTransform', dumpSDP(desc));
+
+        // if we're running on FF, transform to Plan B first.
         if (navigator.mozGetUserMedia) {
             desc = this.interop.toPlanB(desc);
-        } else {
-            desc = APP.simulcast.reverseTransformLocalDescription(this.peerconnection.localDescription);
+            this.trace('getLocalDescription::postTransform (Plan B)', dumpSDP(desc));
         }
-        this.trace('getLocalDescription::postTransform (Plan B)', dumpSDP(desc));
         return desc;
     });
     TraceablePeerConnection.prototype.__defineGetter__('remoteDescription', function() {
-        this.trace('getRemoteDescription::preTransform (Plan A)', dumpSDP(this.peerconnection.remoteDescription));
-        // if we're running on FF, transform to Plan B first.
         var desc = this.peerconnection.remoteDescription;
+        this.trace('getRemoteDescription::preTransform', dumpSDP(desc));
+
+        // if we're running on FF, transform to Plan B first.
         if (navigator.mozGetUserMedia) {
             desc = this.interop.toPlanB(desc);
-        } else {
-            desc = APP.simulcast.reverseTransformRemoteDescription(this.peerconnection.remoteDescription);
+            this.trace('getRemoteDescription::postTransform (Plan B)', dumpSDP(desc));
         }
-        this.trace('getRemoteDescription::postTransform (Plan B)', dumpSDP(desc));
         return desc;
     });
 }
 
 TraceablePeerConnection.prototype.addStream = function (stream) {
     this.trace('addStream', stream.id);
-    APP.simulcast.resetSender();
     try
     {
         this.peerconnection.addStream(stream);
 
 TraceablePeerConnection.prototype.removeStream = function (stream, stopStreams) {
     this.trace('removeStream', stream.id);
-    APP.simulcast.resetSender();
     if(stopStreams) {
         stream.getAudioTracks().forEach(function (track) {
             track.stop();
 };
 
 TraceablePeerConnection.prototype.setLocalDescription = function (description, successCallback, failureCallback) {
-    this.trace('setLocalDescription::preTransform (Plan B)', dumpSDP(description));
+    this.trace('setLocalDescription::preTransform', dumpSDP(description));
     // if we're running on FF, transform to Plan A first.
     if (navigator.mozGetUserMedia) {
         description = this.interop.toUnifiedPlan(description);
-    } else {
-        description = APP.simulcast.transformLocalDescription(description);
+        this.trace('setLocalDescription::postTransform (Plan A)', dumpSDP(description));
     }
-    this.trace('setLocalDescription::postTransform (Plan A)', dumpSDP(description));
+
     var self = this;
     this.peerconnection.setLocalDescription(description,
         function () {
 };
 
 TraceablePeerConnection.prototype.setRemoteDescription = function (description, successCallback, failureCallback) {
-    this.trace('setRemoteDescription::preTransform (Plan B)', dumpSDP(description));
+    this.trace('setRemoteDescription::preTransform', dumpSDP(description));
+    // TODO the focus should squeze or explode the remote simulcast
+    description = this.simulcast.mungeRemoteDescription(description);
+    this.trace('setRemoteDescription::postTransform (simulcast)', dumpSDP(description));
+
     // if we're running on FF, transform to Plan A first.
     if (navigator.mozGetUserMedia) {
         description = this.interop.toUnifiedPlan(description);
+        this.trace('setRemoteDescription::postTransform (Plan A)', dumpSDP(description));
     }
-    else {
-        description = APP.simulcast.transformRemoteDescription(description);
-    }
-    this.trace('setRemoteDescription::postTransform (Plan A)', dumpSDP(description));
     var self = this;
     this.peerconnection.setRemoteDescription(description,
         function () {
     this.trace('createOffer', JSON.stringify(constraints, null, ' '));
     this.peerconnection.createOffer(
         function (offer) {
-            self.trace('createOfferOnSuccess::preTransform (Plan A)', dumpSDP(offer));
+            self.trace('createOfferOnSuccess::preTransform', dumpSDP(offer));
             // if we're running on FF, transform to Plan B first.
+            // NOTE this is not tested because in meet the focus generates the
+            // offer.
             if (navigator.mozGetUserMedia) {
                 offer = self.interop.toPlanB(offer);
+                self.trace('createOfferOnSuccess::postTransform (Plan B)', dumpSDP(offer));
+            }
+
+            if (config.enableSimulcast && self.simulcast.isSupported()) {
+                offer = self.simulcast.mungeLocalDescription(offer);
+                self.trace('createOfferOnSuccess::postTransform (simulcast)', dumpSDP(offer));
             }
-            self.trace('createOfferOnSuccess::postTransform (Plan B)', dumpSDP(offer));
             successCallback(offer);
         },
         function(err) {
     this.trace('createAnswer', JSON.stringify(constraints, null, ' '));
     this.peerconnection.createAnswer(
         function (answer) {
-            self.trace('createAnswerOnSuccess::preTransfom (Plan A)', dumpSDP(answer));
+            self.trace('createAnswerOnSuccess::preTransfom', dumpSDP(answer));
             // if we're running on FF, transform to Plan A first.
             if (navigator.mozGetUserMedia) {
                 answer = self.interop.toPlanB(answer);
-            } else {
-                answer = APP.simulcast.transformAnswer(answer);
+                self.trace('createAnswerOnSuccess::postTransfom (Plan B)', dumpSDP(answer));
+            }
+            if (config.enableSimulcast && self.simulcast.isSupported()) {
+                answer = self.simulcast.mungeLocalDescription(answer);
+                self.trace('createAnswerOnSuccess::postTransfom (simulcast)', dumpSDP(answer));
             }
-            self.trace('createAnswerOnSuccess::postTransfom (Plan B)', dumpSDP(answer));
             successCallback(answer);
         },
         function(err) {

modules/xmpp/moderator.js

                 { name: 'startVideoMuted', value: config.startVideoMuted})
                 .up();
         }
+        elem.c(
+            'property',
+            { name: 'simulcastMode', value: 'rewriting'})
+            .up();
         elem.up();
         return elem;
     },

package.json

       "i18next-client": "1.7.7",
       "sdp-interop": "0.1.4",
       "sdp-transform": "1.4.0",
+      "sdp-simulcast": "0.1.0",
       "async": "0.9.0",
       "retry": "0.6.1"
   },

service/RTC/RTCEvents.js

     LASTN_CHANGED: "rtc.lastn_changed",
     DOMINANTSPEAKER_CHANGED: "rtc.dominantspeaker_changed",
     LASTN_ENDPOINT_CHANGED: "rtc.lastn_endpoint_changed",
-    SIMULCAST_LAYER_CHANGED: "rtc.simulcast_layer_changed",
-    SIMULCAST_LAYER_CHANGING: "rtc.simulcast_layer_changing",
-    SIMULCAST_START: "rtc.simlcast_start",
-    SIMULCAST_STOP: "rtc.simlcast_stop",
     AVAILABLE_DEVICES_CHANGED: "rtc.available_devices_changed"
 };