jitsi_corner8/modules/xmpp/JingleSessionPC.js

/* jshint -W117 */
/* jshint -W101 */
var JingleSession = require("./JingleSession");
var TraceablePeerConnection = require("./TraceablePeerConnection");
var SDPDiffer = require("./SDPDiffer");
var SDPUtil = require("./SDPUtil");
var SDP = require("./SDP");
var async = require("async");
var transform = require("sdp-transform");
var XMPPEvents = require("../../service/xmpp/XMPPEvents");
var RTCBrowserType = require("../RTC/RTCBrowserType");
var SSRCReplacement = require("./LocalSSRCReplacement");

// Jingle stuff
function JingleSessionPC(me, sid, connection, service, eventEmitter) {
    JingleSession.call(this, me, sid, connection, service, eventEmitter);
    this.initiator = null;
    this.responder = null;
    this.peerjid = null;
    this.state = null;
    this.localSDP = null;
    this.remoteSDP = null;
    this.relayedStreams = [];
    this.pc_constraints = null;

    this.usetrickle = true;
    this.usepranswer = false; // early transport warmup -- mind you, this might fail. depends on webrtc issue 1718

    this.hadstuncandidate = false;
    this.hadturncandidate = false;
    this.lasticecandidate = false;

    this.statsinterval = null;

    this.reason = null;

    this.addssrc = [];
    this.removessrc = [];
    this.pendingop = null;
    this.switchstreams = false;

    this.wait = true;
    this.localStreamsSSRC = null;
    this.ssrcOwners = {};
    this.ssrcVideoTypes = {};
    this.eventEmitter = eventEmitter;

    /**
     * The indicator which determines whether the (local) video has been muted
     * in response to a user command in contrast to an automatic decision made
     * by the application logic.
     */
    this.videoMuteByUser = false;
    this.modifySourcesQueue = async.queue(this._modifySources.bind(this), 1);
    // We start with the queue paused. We resume it when the signaling state is
    // stable and the ice connection state is connected.
    this.modifySourcesQueue.pause();
}
//XXX this is badly broken...
JingleSessionPC.prototype = JingleSession.prototype;
JingleSessionPC.prototype.constructor = JingleSessionPC;


JingleSessionPC.prototype.setOffer = function(offer) {
    this.setRemoteDescription(offer, 'offer');
};

JingleSessionPC.prototype.setAnswer = function(answer) {
    this.setRemoteDescription(answer, 'answer');
};

JingleSessionPC.prototype.updateModifySourcesQueue = function() {
    var signalingState = this.peerconnection.signalingState;
    var iceConnectionState = this.peerconnection.iceConnectionState;
    if (signalingState === 'stable' && iceConnectionState === 'connected') {
        this.modifySourcesQueue.resume();
    } else {
        this.modifySourcesQueue.pause();
    }
};

JingleSessionPC.prototype.doInitialize = function () {
    var self = this;

    this.hadstuncandidate = false;
    this.hadturncandidate = false;
    this.lasticecandidate = false;
    // True if reconnect is in progress
    this.isreconnect = false;
    // Set to true if the connection was ever stable
    this.wasstable = false;

    this.peerconnection = new TraceablePeerConnection(
            this.connection.jingle.ice_config,
            this.connection.jingle.pc_constraints,
            this);

    this.peerconnection.onicecandidate = function (event) {
        var protocol;
        if (event && event.candidate) {
            protocol = (typeof event.candidate.protocol === 'string')
                ? event.candidate.protocol.toLowerCase() : '';
            if ((config.webrtcIceTcpDisable && protocol == 'tcp') ||
                (config.webrtcIceUdpDisable && protocol == 'udp')) {
                return;
            }
        }
        self.sendIceCandidate(event.candidate);
    };
    this.peerconnection.onaddstream = function (event) {
        if (event.stream.id !== 'default') {
        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
            // receiving remote stream/tracks, as opposed to Plan B where there
            // are only 3 channels: audio, video and data.
            console.log("RECVONLY REMOTE STREAM IGNORED: " + event.stream + " - " + event.stream.id);
        }
    };
    this.peerconnection.onremovestream = function (event) {
        // Remove the stream from remoteStreams
        // FIXME: remotestreamremoved.jingle not defined anywhere(unused)
        $(document).trigger('remotestreamremoved.jingle', [event, self.sid]);
    };
    this.peerconnection.onsignalingstatechange = function (event) {
        if (!(self && self.peerconnection)) return;
        console.info("Signaling: " + this.peerconnection.signalingState);
        if (self.peerconnection.signalingState === 'stable') {
            self.wasstable = true;
        }
        self.updateModifySourcesQueue();
    };
    /**
     * The oniceconnectionstatechange event handler contains the code to execute when the iceconnectionstatechange event,
     * of type Event, is received by this RTCPeerConnection. Such an event is sent when the value of
     * RTCPeerConnection.iceConnectionState changes.
     *
     * @param event the event containing information about the change
     */
    this.peerconnection.oniceconnectionstatechange = function (event) {
        if (!(self && self.peerconnection)) return;
        console.info("Ice: " + self.peerconnection.iceConnectionState);
        self.updateModifySourcesQueue();
        switch (self.peerconnection.iceConnectionState) {
            case 'connected':

                // Informs interested parties that the connection has been restored.
                if (self.peerconnection.signalingState === 'stable' && self.isreconnect)
                    self.eventEmitter.emit(XMPPEvents.CONNECTION_RESTORED);
                self.isreconnect = false;

                break;
            case 'disconnected':
                self.isreconnect = true;
                // Informs interested parties that the connection has been interrupted.
                if (self.wasstable)
                    self.eventEmitter.emit(XMPPEvents.CONNECTION_INTERRUPTED);
                break;
            case 'failed':
                self.eventEmitter.emit(XMPPEvents.CONFERENCE_SETUP_FAILED);
                break;
        }
        onIceConnectionStateChange(self.sid, self);
    };
    this.peerconnection.onnegotiationneeded = function (event) {
        self.eventEmitter.emit(XMPPEvents.PEERCONNECTION_READY, self);
    };
    // add any local and relayed stream
    APP.RTC.localStreams.forEach(function(stream) {
        self.peerconnection.addStream(stream.getOriginalStream());
    });
    this.relayedStreams.forEach(function(stream) {
        self.peerconnection.addStream(stream);
    });
};

function onIceConnectionStateChange(sid, session) {
    switch (session.peerconnection.iceConnectionState) {
        case 'checking':
            session.timeChecking = (new Date()).getTime();
            session.firstconnect = true;
            break;
        case 'completed': // on caller side
        case 'connected':
            if (session.firstconnect) {
                session.firstconnect = false;
                var metadata = {};
                metadata.setupTime
                    = (new Date()).getTime() - session.timeChecking;
                session.peerconnection.getStats(function (res) {
                    if(res && res.result) {
                        res.result().forEach(function (report) {
                            if (report.type == 'googCandidatePair' &&
                                report.stat('googActiveConnection') == 'true') {
                                metadata.localCandidateType
                                    = report.stat('googLocalCandidateType');
                                metadata.remoteCandidateType
                                    = report.stat('googRemoteCandidateType');

                                // log pair as well so we can get nice pie
                                // charts
                                metadata.candidatePair
                                    = report.stat('googLocalCandidateType') +
                                        ';' +
                                        report.stat('googRemoteCandidateType');

                                if (report.stat('googRemoteAddress').indexOf('[') === 0)
                                {
                                    metadata.ipv6 = true;
                                }
                            }
                        });
                    }
                });
            }
            break;
    }
}

JingleSessionPC.prototype.accept = function () {
    this.state = 'active';

    var pranswer = this.peerconnection.localDescription;
    if (!pranswer || pranswer.type != 'pranswer') {
        return;
    }
    console.log('going from pranswer to answer');
    if (this.usetrickle) {
        // remove candidates already sent from session-accept
        var lines = SDPUtil.find_lines(pranswer.sdp, 'a=candidate:');
        for (var i = 0; i < lines.length; i++) {
            pranswer.sdp = pranswer.sdp.replace(lines[i] + '\r\n', '');
        }
    }
    while (SDPUtil.find_line(pranswer.sdp, 'a=inactive')) {
        // FIXME: change any inactive to sendrecv or whatever they were originally
        pranswer.sdp = pranswer.sdp.replace('a=inactive', 'a=sendrecv');
    }
    var prsdp = new SDP(pranswer.sdp);
    if (config.webrtcIceTcpDisable) {
        prsdp.removeTcpCandidates = true;
    }
    if (config.webrtcIceUdpDisable) {
        prsdp.removeUdpCandidates = true;
    }
    var accept = $iq({to: this.peerjid,
        type: 'set'})
        .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
            action: 'session-accept',
            initiator: this.initiator,
            responder: this.responder,
            sid: this.sid });
    // FIXME why do we generate session-accept in 3 different places ?
    prsdp.toJingle(
        accept,
        this.initiator == this.me ? 'initiator' : 'responder',
        this.localStreamsSSRC);
    var sdp = this.peerconnection.localDescription.sdp;
    while (SDPUtil.find_line(sdp, 'a=inactive')) {
        // FIXME: change any inactive to sendrecv or whatever they were originally
        sdp = sdp.replace('a=inactive', 'a=sendrecv');
    }
    var self = this;
    this.peerconnection.setLocalDescription(new RTCSessionDescription({type: 'answer', sdp: sdp}),
        function () {
            //console.log('setLocalDescription success');
            self.setLocalDescription();

            SSRCReplacement.processSessionInit(accept);

            self.connection.sendIQ(accept,
                function () {
                    var ack = {};
                    ack.source = 'answer';
                    $(document).trigger('ack.jingle', [self.sid, ack]);
                },
                function (stanza) {
                    var error = ($(stanza).find('error').length) ? {
                        code: $(stanza).find('error').attr('code'),
                        reason: $(stanza).find('error :first')[0].tagName
                    }:{};
                    error.source = 'answer';
                    JingleSessionPC.onJingleError(self.sid, error);
                },
                10000);
        },
        function (e) {
            console.error('setLocalDescription failed', e);
            self.eventEmitter.emit(XMPPEvents.CONFERENCE_SETUP_FAILED);
        }
    );
};

JingleSessionPC.prototype.terminate = function (reason) {
    this.state = 'ended';
    this.reason = reason;
    this.peerconnection.close();
    if (this.statsinterval !== null) {
        window.clearInterval(this.statsinterval);
        this.statsinterval = null;
    }
};

JingleSessionPC.prototype.active = function () {
    return this.state == 'active';
};

JingleSessionPC.prototype.sendIceCandidate = function (candidate) {
    var self = this;
    if (candidate && !this.lasticecandidate) {
        var ice = SDPUtil.iceparams(this.localSDP.media[candidate.sdpMLineIndex], this.localSDP.session);
        var jcand = SDPUtil.candidateToJingle(candidate.candidate);
        if (!(ice && jcand)) {
            console.error('failed to get ice && jcand');
            return;
        }
        ice.xmlns = 'urn:xmpp:jingle:transports:ice-udp:1';

        if (jcand.type === 'srflx') {
            this.hadstuncandidate = true;
        } else if (jcand.type === 'relay') {
            this.hadturncandidate = true;
        }

        if (this.usetrickle) {
            if (this.usedrip) {
                if (this.drip_container.length === 0) {
                    // start 20ms callout
                    window.setTimeout(function () {
                        if (self.drip_container.length === 0) return;
                        self.sendIceCandidates(self.drip_container);
                        self.drip_container = [];
                    }, 20);

                }
                this.drip_container.push(candidate);
                return;
            } else {
                self.sendIceCandidate([candidate]);
            }
        }
    } else {
        //console.log('sendIceCandidate: last candidate.');
        if (!this.usetrickle) {
            //console.log('should send full offer now...');
            //FIXME why do we generate session-accept in 3 different places ?
            var init = $iq({to: this.peerjid,
                type: 'set'})
                .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
                    action: this.peerconnection.localDescription.type == 'offer' ? 'session-initiate' : 'session-accept',
                    initiator: this.initiator,
                    sid: this.sid});
            this.localSDP = new SDP(this.peerconnection.localDescription.sdp);
            if (config.webrtcIceTcpDisable) {
                this.localSDP.removeTcpCandidates = true;
            }
            if (config.webrtcIceUdpDisable) {
                this.localSDP.removeUdpCandidates = true;
            }
            var sendJingle = function (ssrc) {
                if(!ssrc)
                    ssrc = {};
                self.localSDP.toJingle(
                    init,
                    self.initiator == self.me ? 'initiator' : 'responder',
                    ssrc);

                SSRCReplacement.processSessionInit(init);

                self.connection.sendIQ(init,
                    function () {
                        //console.log('session initiate ack');
                        var ack = {};
                        ack.source = 'offer';
                        $(document).trigger('ack.jingle', [self.sid, ack]);
                    },
                    function (stanza) {
                        self.state = 'error';
                        self.peerconnection.close();
                        var error = ($(stanza).find('error').length) ? {
                            code: $(stanza).find('error').attr('code'),
                            reason: $(stanza).find('error :first')[0].tagName,
                        }:{};
                        error.source = 'offer';
                        JingleSessionPC.onJingleError(self.sid, error);
                    },
                    10000);
            };
            sendJingle();
        }
        this.lasticecandidate = true;
        console.log('Have we encountered any srflx candidates? ' + this.hadstuncandidate);
        console.log('Have we encountered any relay candidates? ' + this.hadturncandidate);

        if (!(this.hadstuncandidate || this.hadturncandidate) && this.peerconnection.signalingState != 'closed') {
            $(document).trigger('nostuncandidates.jingle', [this.sid]);
        }
    }
};

JingleSessionPC.prototype.sendIceCandidates = function (candidates) {
    console.log('sendIceCandidates', candidates);
    var cand = $iq({to: this.peerjid, type: 'set'})
        .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
            action: 'transport-info',
            initiator: this.initiator,
            sid: this.sid});
    for (var mid = 0; mid < this.localSDP.media.length; mid++) {
        var cands = candidates.filter(function (el) { return el.sdpMLineIndex == mid; });
        var mline = SDPUtil.parse_mline(this.localSDP.media[mid].split('\r\n')[0]);
        if (cands.length > 0) {
            var ice = SDPUtil.iceparams(this.localSDP.media[mid], this.localSDP.session);
            ice.xmlns = 'urn:xmpp:jingle:transports:ice-udp:1';
            cand.c('content', {creator: this.initiator == this.me ? 'initiator' : 'responder',
                name: (cands[0].sdpMid? cands[0].sdpMid : mline.media)
            }).c('transport', ice);
            for (var i = 0; i < cands.length; i++) {
                cand.c('candidate', SDPUtil.candidateToJingle(cands[i].candidate)).up();
            }
            // add fingerprint
            if (SDPUtil.find_line(this.localSDP.media[mid], 'a=fingerprint:', this.localSDP.session)) {
                var tmp = SDPUtil.parse_fingerprint(SDPUtil.find_line(this.localSDP.media[mid], 'a=fingerprint:', this.localSDP.session));
                tmp.required = true;
                cand.c(
                    'fingerprint',
                    {xmlns: 'urn:xmpp:jingle:apps:dtls:0'})
                    .t(tmp.fingerprint);
                delete tmp.fingerprint;
                cand.attrs(tmp);
                cand.up();
            }
            cand.up(); // transport
            cand.up(); // content
        }
    }
    // might merge last-candidate notification into this, but it is called alot later. See webrtc issue #2340
    //console.log('was this the last candidate', this.lasticecandidate);
    this.connection.sendIQ(cand,
        function () {
            var ack = {};
            ack.source = 'transportinfo';
            $(document).trigger('ack.jingle', [this.sid, ack]);
        },
        function (stanza) {
            var error = ($(stanza).find('error').length) ? {
                code: $(stanza).find('error').attr('code'),
                reason: $(stanza).find('error :first')[0].tagName,
            }:{};
            error.source = 'transportinfo';
            JingleSessionPC.onJingleError(this.sid, error);
        },
        10000);
};


JingleSessionPC.prototype.sendOffer = function () {
    //console.log('sendOffer...');
    var self = this;
    this.peerconnection.createOffer(function (sdp) {
            self.createdOffer(sdp);
        },
        function (e) {
            console.error('createOffer failed', e);
        },
        this.media_constraints
    );
};

// FIXME createdOffer is never used in jitsi-meet
JingleSessionPC.prototype.createdOffer = function (sdp) {
    //console.log('createdOffer', sdp);
    var self = this;
    this.localSDP = new SDP(sdp.sdp);
    //this.localSDP.mangle();
    var sendJingle = function () {
        var init = $iq({to: this.peerjid,
            type: 'set'})
            .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
                action: 'session-initiate',
                initiator: this.initiator,
                sid: this.sid});
        self.localSDP.toJingle(
            init,
            this.initiator == this.me ? 'initiator' : 'responder',
            this.localStreamsSSRC);

        SSRCReplacement.processSessionInit(init);

        self.connection.sendIQ(init,
            function () {
                var ack = {};
                ack.source = 'offer';
                $(document).trigger('ack.jingle', [self.sid, ack]);
            },
            function (stanza) {
                self.state = 'error';
                self.peerconnection.close();
                var error = ($(stanza).find('error').length) ? {
                    code: $(stanza).find('error').attr('code'),
                    reason: $(stanza).find('error :first')[0].tagName,
                }:{};
                error.source = 'offer';
                JingleSessionPC.onJingleError(self.sid, error);
            },
            10000);
    };
    sdp.sdp = this.localSDP.raw;
    this.peerconnection.setLocalDescription(sdp,
        function () {
            if(self.usetrickle)
            {
                sendJingle();
            }
            self.setLocalDescription();
            //console.log('setLocalDescription success');
        },
        function (e) {
            console.error('setLocalDescription failed', e);
            self.eventEmitter.emit(XMPPEvents.CONFERENCE_SETUP_FAILED);
        }
    );
    var cands = SDPUtil.find_lines(this.localSDP.raw, 'a=candidate:');
    for (var i = 0; i < cands.length; i++) {
        var cand = SDPUtil.parse_icecandidate(cands[i]);
        if (cand.type == 'srflx') {
            this.hadstuncandidate = true;
        } else if (cand.type == 'relay') {
            this.hadturncandidate = true;
        }
    }
};

JingleSessionPC.prototype.readSsrcInfo = function (contents) {
    var self = this;
    $(contents).each(function (idx, content) {
        var name = $(content).attr('name');
        var mediaType = this.getAttribute('name');
        var ssrcs = $(content).find('description>source[xmlns="urn:xmpp:jingle:apps:rtp:ssma:0"]');
        ssrcs.each(function () {
            var ssrc = this.getAttribute('ssrc');
            $(this).find('>ssrc-info[xmlns="http://jitsi.org/jitmeet"]').each(
                function () {
                    var owner = this.getAttribute('owner');
                    self.ssrcOwners[ssrc] = owner;
                }
            );
        });
    });
};

JingleSessionPC.prototype.getSsrcOwner = function (ssrc) {
    return this.ssrcOwners[ssrc];
};

JingleSessionPC.prototype.setRemoteDescription = function (elem, desctype) {
    this.remoteSDP = new SDP('');
    if (config.webrtcIceTcpDisable) {
        this.remoteSDP.removeTcpCandidates = true;
    }
    if (config.webrtcIceUdpDisable) {
        this.remoteSDP.removeUdpCandidates = true;
    }

    this.remoteSDP.fromJingle(elem);
    this.readSsrcInfo($(elem).find(">content"));
    if (this.peerconnection.remoteDescription !== null) {
        console.log('setRemoteDescription when remote description is not null, should be pranswer', this.peerconnection.remoteDescription);
        if (this.peerconnection.remoteDescription.type == 'pranswer') {
            var pranswer = new SDP(this.peerconnection.remoteDescription.sdp);
            for (var i = 0; i < pranswer.media.length; i++) {
                // make sure we have ice ufrag and pwd
                if (!SDPUtil.find_line(this.remoteSDP.media[i], 'a=ice-ufrag:', this.remoteSDP.session)) {
                    if (SDPUtil.find_line(pranswer.media[i], 'a=ice-ufrag:', pranswer.session)) {
                        this.remoteSDP.media[i] += SDPUtil.find_line(pranswer.media[i], 'a=ice-ufrag:', pranswer.session) + '\r\n';
                    } else {
                        console.warn('no ice ufrag?');
                    }
                    if (SDPUtil.find_line(pranswer.media[i], 'a=ice-pwd:', pranswer.session)) {
                        this.remoteSDP.media[i] += SDPUtil.find_line(pranswer.media[i], 'a=ice-pwd:', pranswer.session) + '\r\n';
                    } else {
                        console.warn('no ice pwd?');
                    }
                }
                // copy over candidates
                var lines = SDPUtil.find_lines(pranswer.media[i], 'a=candidate:');
                for (var j = 0; j < lines.length; j++) {
                    this.remoteSDP.media[i] += lines[j] + '\r\n';
                }
            }
            this.remoteSDP.raw = this.remoteSDP.session + this.remoteSDP.media.join('');
        }
    }
    var remotedesc = new RTCSessionDescription({type: desctype, sdp: this.remoteSDP.raw});

    this.peerconnection.setRemoteDescription(remotedesc,
        function () {
            //console.log('setRemoteDescription success');
        },
        function (e) {
            console.error('setRemoteDescription error', e);
            JingleSessionPC.onJingleFatalError(self, e);
        }
    );
};

/**
 * Adds remote ICE candidates to this Jingle session.
 * @param elem An array of Jingle "content" elements?
 */
JingleSessionPC.prototype.addIceCandidate = function (elem) {
    var self = this;
    if (this.peerconnection.signalingState == 'closed') {
        return;
    }
    if (!this.peerconnection.remoteDescription && this.peerconnection.signalingState == 'have-local-offer') {
        console.log('trickle ice candidate arriving before session accept...');
        // create a PRANSWER for setRemoteDescription
        if (!this.remoteSDP) {
            var cobbled = 'v=0\r\n' +
                'o=- 1923518516 2 IN IP4 0.0.0.0\r\n' +// FIXME
                's=-\r\n' +
                't=0 0\r\n';
            // first, take some things from the local description
            for (var i = 0; i < this.localSDP.media.length; i++) {
                cobbled += SDPUtil.find_line(this.localSDP.media[i], 'm=') + '\r\n';
                cobbled += SDPUtil.find_lines(this.localSDP.media[i], 'a=rtpmap:').join('\r\n') + '\r\n';
                if (SDPUtil.find_line(this.localSDP.media[i], 'a=mid:')) {
                    cobbled += SDPUtil.find_line(this.localSDP.media[i], 'a=mid:') + '\r\n';
                }
                cobbled += 'a=inactive\r\n';
            }
            this.remoteSDP = new SDP(cobbled);
        }
        // then add things like ice and dtls from remote candidate
        elem.each(function () {
            for (var i = 0; i < self.remoteSDP.media.length; i++) {
                if (SDPUtil.find_line(self.remoteSDP.media[i], 'a=mid:' + $(this).attr('name')) ||
                    self.remoteSDP.media[i].indexOf('m=' + $(this).attr('name')) === 0) {
                    if (!SDPUtil.find_line(self.remoteSDP.media[i], 'a=ice-ufrag:')) {
                        var tmp = $(this).find('transport');
                        self.remoteSDP.media[i] += 'a=ice-ufrag:' + tmp.attr('ufrag') + '\r\n';
                        self.remoteSDP.media[i] += 'a=ice-pwd:' + tmp.attr('pwd') + '\r\n';
                        tmp = $(this).find('transport>fingerprint');
                        if (tmp.length) {
                            self.remoteSDP.media[i] += 'a=fingerprint:' + tmp.attr('hash') + ' ' + tmp.text() + '\r\n';
                        } else {
                            console.log('no dtls fingerprint (webrtc issue #1718?)');
                            self.remoteSDP.media[i] += 'a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:BAADBAADBAADBAADBAADBAADBAADBAADBAADBAAD\r\n';
                        }
                        break;
                    }
                }
            }
        });
        this.remoteSDP.raw = this.remoteSDP.session + this.remoteSDP.media.join('');

        // we need a complete SDP with ice-ufrag/ice-pwd in all parts
        // this makes the assumption that the PRANSWER is constructed such that the ice-ufrag is in all mediaparts
        // but it could be in the session part as well. since the code above constructs this sdp this can't happen however
        var iscomplete = this.remoteSDP.media.filter(function (mediapart) {
            return SDPUtil.find_line(mediapart, 'a=ice-ufrag:');
        }).length == this.remoteSDP.media.length;

        if (iscomplete) {
            console.log('setting pranswer');
            try {
                this.peerconnection.setRemoteDescription(new RTCSessionDescription({type: 'pranswer', sdp: this.remoteSDP.raw }),
                    function() {
                    },
                    function(e) {
                        console.log('setRemoteDescription pranswer failed', e.toString());
                    });
            } catch (e) {
                console.error('setting pranswer failed', e);
            }
        } else {
            //console.log('not yet setting pranswer');
        }
    }
    // operate on each content element
    elem.each(function () {
        // would love to deactivate this, but firefox still requires it
        var idx = -1;
        var i;
        for (i = 0; i < self.remoteSDP.media.length; i++) {
            if (SDPUtil.find_line(self.remoteSDP.media[i], 'a=mid:' + $(this).attr('name')) ||
                self.remoteSDP.media[i].indexOf('m=' + $(this).attr('name')) === 0) {
                idx = i;
                break;
            }
        }
        if (idx == -1) { // fall back to localdescription
            for (i = 0; i < self.localSDP.media.length; i++) {
                if (SDPUtil.find_line(self.localSDP.media[i], 'a=mid:' + $(this).attr('name')) ||
                    self.localSDP.media[i].indexOf('m=' + $(this).attr('name')) === 0) {
                    idx = i;
                    break;
                }
            }
        }
        var name = $(this).attr('name');
        // TODO: check ice-pwd and ice-ufrag?
        $(this).find('transport>candidate').each(function () {
            var line, candidate;
            var protocol = this.getAttribute('protocol');
            protocol =
                (typeof protocol === 'string') ? protocol.toLowerCase() : '';
            if ((config.webrtcIceTcpDisable && protocol == 'tcp') ||
                (config.webrtcIceUdpDisable && protocol == 'udp')) {
                return;
            }

            line = SDPUtil.candidateFromJingle(this);
            candidate = new RTCIceCandidate({sdpMLineIndex: idx,
                sdpMid: name,
                candidate: line});
            try {
                self.peerconnection.addIceCandidate(candidate);
            } catch (e) {
                console.error('addIceCandidate failed', e.toString(), line);
            }
        });
    });
};

JingleSessionPC.prototype.sendAnswer = function (provisional) {
    //console.log('createAnswer', provisional);
    var self = this;
    this.peerconnection.createAnswer(
        function (sdp) {
            self.createdAnswer(sdp, provisional);
        },
        function (e) {
            console.error('createAnswer failed', e);
            self.eventEmitter.emit(XMPPEvents.CONFERENCE_SETUP_FAILED);
        },
        this.media_constraints
    );
};

JingleSessionPC.prototype.createdAnswer = function (sdp, provisional) {
    //console.log('createAnswer callback');
    var self = this;
    this.localSDP = new SDP(sdp.sdp);
    //this.localSDP.mangle();
    this.usepranswer = provisional === true;
    if (this.usetrickle) {
        if (this.usepranswer) {
            sdp.type = 'pranswer';
            for (var i = 0; i < this.localSDP.media.length; i++) {
                this.localSDP.media[i] = this.localSDP.media[i].replace('a=sendrecv\r\n', 'a=inactive\r\n');
            }
            this.localSDP.raw = this.localSDP.session + '\r\n' + this.localSDP.media.join('');
        }
    }
    var sendJingle = function (ssrcs) {
                // FIXME why do we generate session-accept in 3 different places ?
                var accept = $iq({to: self.peerjid,
                    type: 'set'})
                    .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
                        action: 'session-accept',
                        initiator: self.initiator,
                        responder: self.responder,
                        sid: self.sid });
                if (config.webrtcIceTcpDisable) {
                    self.localSDP.removeTcpCandidates = true;
                }
                if (config.webrtcIceUdpDisable) {
                    self.localSDP.removeUdpCandidates = true;
                }
                self.localSDP.toJingle(
                    accept,
                    self.initiator == self.me ? 'initiator' : 'responder',
                    ssrcs);

                SSRCReplacement.processSessionInit(accept);

                self.connection.sendIQ(accept,
                    function () {
                        var ack = {};
                        ack.source = 'answer';
                        $(document).trigger('ack.jingle', [self.sid, ack]);
                    },
                    function (stanza) {
                        var error = ($(stanza).find('error').length) ? {
                            code: $(stanza).find('error').attr('code'),
                            reason: $(stanza).find('error :first')[0].tagName,
                        }:{};
                        error.source = 'answer';
                        JingleSessionPC.onJingleError(self.sid, error);
                    },
                    10000);
    };
    sdp.sdp = this.localSDP.raw;
    this.peerconnection.setLocalDescription(sdp,
        function () {

            //console.log('setLocalDescription success');
            if (self.usetrickle && !self.usepranswer) {
                sendJingle();
            }
            self.setLocalDescription();
        },
        function (e) {
            console.error('setLocalDescription failed', e);
            self.eventEmitter.emit(XMPPEvents.CONFERENCE_SETUP_FAILED);
        }
    );
    var cands = SDPUtil.find_lines(this.localSDP.raw, 'a=candidate:');
    for (var j = 0; j < cands.length; j++) {
        var cand = SDPUtil.parse_icecandidate(cands[j]);
        if (cand.type == 'srflx') {
            this.hadstuncandidate = true;
        } else if (cand.type == 'relay') {
            this.hadturncandidate = true;
        }
    }
};

JingleSessionPC.prototype.sendTerminate = function (reason, text) {
    var self = this,
        term = $iq({to: this.peerjid,
            type: 'set'})
            .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
                action: 'session-terminate',
                initiator: this.initiator,
                sid: this.sid})
            .c('reason')
            .c(reason || 'success');

    if (text) {
        term.up().c('text').t(text);
    }

    this.connection.sendIQ(term,
        function () {
            self.peerconnection.close();
            self.peerconnection = null;
            self.terminate();
            var ack = {};
            ack.source = 'terminate';
            $(document).trigger('ack.jingle', [self.sid, ack]);
        },
        function (stanza) {
            var error = ($(stanza).find('error').length) ? {
                code: $(stanza).find('error').attr('code'),
                reason: $(stanza).find('error :first')[0].tagName,
            }:{};
            $(document).trigger('ack.jingle', [self.sid, error]);
        },
        10000);
    if (this.statsinterval !== null) {
        window.clearInterval(this.statsinterval);
        this.statsinterval = null;
    }
};

JingleSessionPC.prototype.addSource = function (elem, fromJid) {

    var self = this;
    // FIXME: dirty waiting
    if (!this.peerconnection.localDescription) {
        console.warn("addSource - localDescription not ready yet");
        setTimeout(function()
            {
                self.addSource(elem, fromJid);
            },
            200
        );
        return;
    }

    console.log('addssrc', new Date().getTime());
    console.log('ice', this.peerconnection.iceConnectionState);

    this.readSsrcInfo(elem);

    var sdp = new SDP(this.peerconnection.remoteDescription.sdp);
    var mySdp = new SDP(this.peerconnection.localDescription.sdp);

    $(elem).each(function (idx, content) {
        var name = $(content).attr('name');
        var lines = '';
        $(content).find('ssrc-group[xmlns="urn:xmpp:jingle:apps:rtp:ssma:0"]').each(function() {
            var semantics = this.getAttribute('semantics');
            var ssrcs = $(this).find('>source').map(function () {
                return this.getAttribute('ssrc');
            }).get();

            if (!ssrcs.length) {
                lines += 'a=ssrc-group:' + semantics + ' ' + ssrcs.join(' ') + '\r\n';
            }
        });
        var tmp = $(content).find('source[xmlns="urn:xmpp:jingle:apps:rtp:ssma:0"]'); // can handle both >source and >description>source
        tmp.each(function () {
            var ssrc = $(this).attr('ssrc');
            if(mySdp.containsSSRC(ssrc)){
                /**
                 * This happens when multiple participants change their streams at the same time and
                 * ColibriFocus.modifySources have to wait for stable state. In the meantime multiple
                 * addssrc are scheduled for update IQ. See
                 */
                console.warn("Got add stream request for my own ssrc: "+ssrc);
                return;
            }
            if (sdp.containsSSRC(ssrc)) {
                console.warn("Source-add request for existing SSRC: " + ssrc);
                return;
            }
            $(this).find('>parameter').each(function () {
                lines += 'a=ssrc:' + ssrc + ' ' + $(this).attr('name');
                if ($(this).attr('value') && $(this).attr('value').length)
                    lines += ':' + $(this).attr('value');
                lines += '\r\n';
            });
        });
        sdp.media.forEach(function(media, idx) {
            if (!SDPUtil.find_line(media, 'a=mid:' + name))
                return;
            sdp.media[idx] += lines;
            if (!self.addssrc[idx]) self.addssrc[idx] = '';
            self.addssrc[idx] += lines;
        });
        sdp.raw = sdp.session + sdp.media.join('');
    });

    this.modifySourcesQueue.push(function() {
        // When a source is added and if this is FF, a new channel is allocated
        // for receiving the added source. We need to diffuse the SSRC of this
        // new recvonly channel to the rest of the peers.
        console.log('modify sources done');

        var newSdp = new SDP(self.peerconnection.localDescription.sdp);
        console.log("SDPs", mySdp, newSdp);
        self.notifyMySSRCUpdate(mySdp, newSdp);
    });
};

JingleSessionPC.prototype.removeSource = function (elem, fromJid) {

    var self = this;
    // FIXME: dirty waiting
    if (!this.peerconnection.localDescription) {
        console.warn("removeSource - localDescription not ready yet");
        setTimeout(function() {
                self.removeSource(elem, fromJid);
            },
            200
        );
        return;
    }

    console.log('removessrc', new Date().getTime());
    console.log('ice', this.peerconnection.iceConnectionState);
    var sdp = new SDP(this.peerconnection.remoteDescription.sdp);
    var mySdp = new SDP(this.peerconnection.localDescription.sdp);

    $(elem).each(function (idx, content) {
        var name = $(content).attr('name');
        var lines = '';
        $(content).find('ssrc-group[xmlns="urn:xmpp:jingle:apps:rtp:ssma:0"]').each(function() {
            var semantics = this.getAttribute('semantics');
            var ssrcs = $(this).find('>source').map(function () {
                return this.getAttribute('ssrc');
            }).get();

            if (ssrcs.length) {
                lines += 'a=ssrc-group:' + semantics + ' ' + ssrcs.join(' ') + '\r\n';
            }
        });
        var tmp = $(content).find('source[xmlns="urn:xmpp:jingle:apps:rtp:ssma:0"]'); // can handle both >source and >description>source
        tmp.each(function () {
            var ssrc = $(this).attr('ssrc');
            // This should never happen, but can be useful for bug detection
            if(mySdp.containsSSRC(ssrc)){
                console.error("Got remove stream request for my own ssrc: "+ssrc);
                return;
            }
            $(this).find('>parameter').each(function () {
                lines += 'a=ssrc:' + ssrc + ' ' + $(this).attr('name');
                if ($(this).attr('value') && $(this).attr('value').length)
                    lines += ':' + $(this).attr('value');
                lines += '\r\n';
            });
        });
        sdp.media.forEach(function(media, idx) {
            if (!SDPUtil.find_line(media, 'a=mid:' + name))
                return;
            sdp.media[idx] += lines;
            if (!self.removessrc[idx]) self.removessrc[idx] = '';
            self.removessrc[idx] += lines;
        });
        sdp.raw = sdp.session + sdp.media.join('');
    });

    this.modifySourcesQueue.push(function() {
        // When a source is removed and if this is FF, the recvonly channel that
        // receives the remote stream is deactivated . We need to diffuse the
        // recvonly SSRC removal to the rest of the peers.
        console.log('modify sources done');

        var newSdp = new SDP(self.peerconnection.localDescription.sdp);
        console.log("SDPs", mySdp, newSdp);
        self.notifyMySSRCUpdate(mySdp, newSdp);
    });
};

JingleSessionPC.prototype._modifySources = function (successCallback, queueCallback) {
    var self = this;

    if (this.peerconnection.signalingState == 'closed') return;
    if (!(this.addssrc.length || this.removessrc.length || this.pendingop !== null || this.switchstreams)){
        // There is nothing to do since scheduled job might have been executed by another succeeding call
        this.setLocalDescription();
        if(successCallback){
            successCallback();
        }
        queueCallback();
        return;
    }

    // Reset switch streams flag
    this.switchstreams = false;

    var sdp = new SDP(this.peerconnection.remoteDescription.sdp);

    // add sources
    this.addssrc.forEach(function(lines, idx) {
        sdp.media[idx] += lines;
    });
    this.addssrc = [];

    // remove sources
    this.removessrc.forEach(function(lines, idx) {
        lines = lines.split('\r\n');
        lines.pop(); // remove empty last element;
        lines.forEach(function(line) {
            sdp.media[idx] = sdp.media[idx].replace(line + '\r\n', '');
        });
    });
    this.removessrc = [];

    sdp.raw = sdp.session + sdp.media.join('');
    this.peerconnection.setRemoteDescription(new RTCSessionDescription({type: 'offer', sdp: sdp.raw}),
        function() {

            if(self.signalingState == 'closed') {
                console.error("createAnswer attempt on closed state");
                queueCallback("createAnswer attempt on closed state");
                return;
            }

            self.peerconnection.createAnswer(
                function(modifiedAnswer) {
                    // change video direction, see https://github.com/jitsi/jitmeet/issues/41
                    if (self.pendingop !== null) {
                        var sdp = new SDP(modifiedAnswer.sdp);
                        if (sdp.media.length > 1) {
                            switch(self.pendingop) {
                                case 'mute':
                                    sdp.media[1] = sdp.media[1].replace('a=sendrecv', 'a=recvonly');
                                    break;
                                case 'unmute':
                                    sdp.media[1] = sdp.media[1].replace('a=recvonly', 'a=sendrecv');
                                    break;
                            }
                            sdp.raw = sdp.session + sdp.media.join('');
                            modifiedAnswer.sdp = sdp.raw;
                        }
                        self.pendingop = null;
                    }

                    // FIXME: pushing down an answer while ice connection state
                    // is still checking is bad...
                    //console.log(self.peerconnection.iceConnectionState);

                    // trying to work around another chrome bug
                    //modifiedAnswer.sdp = modifiedAnswer.sdp.replace(/a=setup:active/g, 'a=setup:actpass');
                    self.peerconnection.setLocalDescription(modifiedAnswer,
                        function() {
                            //console.log('modified setLocalDescription ok');
                            self.setLocalDescription();
                            if(successCallback){
                                successCallback();
                            }
                            queueCallback();
                        },
                        function(error) {
                            console.error('modified setLocalDescription failed', error);
                            queueCallback(error);
                        }
                    );
                },
                function(error) {
                    console.error('modified answer failed', error);
                    queueCallback(error);
                }
            );
        },
        function(error) {
            console.error('modify failed', error);
            queueCallback(error);
        }
    );
};


/**
 * Switches video streams.
 * @param newStream new stream that will be used as video of this session.
 * @param oldStream old video stream of this session.
 * @param successCallback callback executed after successful stream switch.
 */
JingleSessionPC.prototype.switchStreams = function (newStream, oldStream, successCallback) {

    var self = this;

    // Remember SDP to figure out added/removed SSRCs
    var oldSdp = null;
    if (self.peerconnection) {
        if (self.peerconnection.localDescription) {
            oldSdp = new SDP(self.peerconnection.localDescription.sdp);
        }
        self.peerconnection.removeStream(oldStream, true);
        if (newStream)
            self.peerconnection.addStream(newStream);
    }

    // Conference is not active
    if (!oldSdp) {
        successCallback();
        return;
    }

    self.switchstreams = true;
    self.modifySourcesQueue.push(function() {
        console.log('modify sources done');

        successCallback();

        var newSdp = new SDP(self.peerconnection.localDescription.sdp);
        console.log("SDPs", oldSdp, newSdp);
        self.notifyMySSRCUpdate(oldSdp, newSdp);
    });
};

/**
 * Figures out added/removed ssrcs and send update IQs.
 * @param old_sdp SDP object for old description.
 * @param new_sdp SDP object for new description.
 */
JingleSessionPC.prototype.notifyMySSRCUpdate = function (old_sdp, new_sdp) {

    if (!(this.peerconnection.signalingState == 'stable' &&
        this.peerconnection.iceConnectionState == 'connected')){
        console.log("Too early to send updates");
        return;
    }

    // send source-remove IQ.
    sdpDiffer = new SDPDiffer(new_sdp, old_sdp);
    var remove = $iq({to: this.peerjid, type: 'set'})
        .c('jingle', {
            xmlns: 'urn:xmpp:jingle:1',
            action: 'source-remove',
            initiator: this.initiator,
            sid: this.sid
        }
    );
    var removed = sdpDiffer.toJingle(remove);

    // Let 'source-remove' IQ through the hack and see if we're allowed to send
    // it in the current form
    if (removed)
        remove = SSRCReplacement.processSourceRemove(remove);

    if (removed && remove) {
        console.info("Sending source-remove", remove);
        this.connection.sendIQ(remove,
            function (res) {
                console.info('got remove result', res);
            },
            function (err) {
                console.error('got remove error', err);
            }
        );
    } else {
        console.log('removal not necessary');
    }

    // send source-add IQ.
    var sdpDiffer = new SDPDiffer(old_sdp, new_sdp);
    var add = $iq({to: this.peerjid, type: 'set'})
        .c('jingle', {
            xmlns: 'urn:xmpp:jingle:1',
            action: 'source-add',
            initiator: this.initiator,
            sid: this.sid
        }
    );
    var added = sdpDiffer.toJingle(add);

    // Let 'source-add' IQ through the hack and see if we're allowed to send
    // it in the current form
    if (added)
        add = SSRCReplacement.processSourceAdd(add);

    if (added && add) {
        console.info("Sending source-add", add);
        this.connection.sendIQ(add,
            function (res) {
                console.info('got add result', res);
            },
            function (err) {
                console.error('got add error', err);
            }
        );
    } else {
        console.log('addition not necessary');
    }
};

/**
 * Mutes/unmutes the (local) video i.e. enables/disables all video tracks.
 *
 * @param mute <tt>true</tt> to mute the (local) video i.e. to disable all video
 * tracks; otherwise, <tt>false</tt>
 * @param callback a function to be invoked with <tt>mute</tt> after all video
 * tracks have been enabled/disabled. The function may, optionally, return
 * another function which is to be invoked after the whole mute/unmute operation
 * has completed successfully.
 * @param options an object which specifies optional arguments such as the
 * <tt>boolean</tt> key <tt>byUser</tt> with default value <tt>true</tt> which
 * specifies whether the method was initiated in response to a user command (in
 * contrast to an automatic decision made by the application logic)
 */
JingleSessionPC.prototype.setVideoMute = function (mute, callback, options) {
    var byUser;

    if (options) {
        byUser = options.byUser;
        if (typeof byUser === 'undefined') {
            byUser = true;
        }
    } else {
        byUser = true;
    }
    // The user's command to mute the (local) video takes precedence over any
    // automatic decision made by the application logic.
    if (byUser) {
        this.videoMuteByUser = mute;
    } else if (this.videoMuteByUser) {
        return;
    }

    this.hardMuteVideo(mute);

    var self = this;
    var oldSdp = null;
    if(self.peerconnection) {
        if(self.peerconnection.localDescription) {
            oldSdp = new SDP(self.peerconnection.localDescription.sdp);
        }
    }

    this.modifySourcesQueue.push(function() {
        console.log('modify sources done');

        callback(mute);

        var newSdp = new SDP(self.peerconnection.localDescription.sdp);
        console.log("SDPs", oldSdp, newSdp);
        self.notifyMySSRCUpdate(oldSdp, newSdp);
    });
};

JingleSessionPC.prototype.hardMuteVideo = function (muted) {
    this.pendingop = muted ? 'mute' : 'unmute';
};

JingleSessionPC.prototype.sendMute = function (muted, content) {
    var info = $iq({to: this.peerjid,
        type: 'set'})
        .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
            action: 'session-info',
            initiator: this.initiator,
            sid: this.sid });
    info.c(muted ? 'mute' : 'unmute', {xmlns: 'urn:xmpp:jingle:apps:rtp:info:1'});
    info.attrs({'creator': this.me == this.initiator ? 'creator' : 'responder'});
    if (content) {
        info.attrs({'name': content});
    }
    this.connection.send(info);
};

JingleSessionPC.prototype.sendRinging = function () {
    var info = $iq({to: this.peerjid,
        type: 'set'})
        .c('jingle', {xmlns: 'urn:xmpp:jingle:1',
            action: 'session-info',
            initiator: this.initiator,
            sid: this.sid });
    info.c('ringing', {xmlns: 'urn:xmpp:jingle:apps:rtp:info:1'});
    this.connection.send(info);
};

JingleSessionPC.prototype.getStats = function (interval) {
    var self = this;
    var recv = {audio: 0, video: 0};
    var lost = {audio: 0, video: 0};
    var lastrecv = {audio: 0, video: 0};
    var lastlost = {audio: 0, video: 0};
    var loss = {audio: 0, video: 0};
    var delta = {audio: 0, video: 0};
    this.statsinterval = window.setInterval(function () {
        if (self && self.peerconnection && self.peerconnection.getStats) {
            self.peerconnection.getStats(function (stats) {
                var results = stats.result();
                // TODO: there are so much statistics you can get from this..
                for (var i = 0; i < results.length; ++i) {
                    if (results[i].type == 'ssrc') {
                        var packetsrecv = results[i].stat('packetsReceived');
                        var packetslost = results[i].stat('packetsLost');
                        if (packetsrecv && packetslost) {
                            packetsrecv = parseInt(packetsrecv, 10);
                            packetslost = parseInt(packetslost, 10);

                            if (results[i].stat('googFrameRateReceived')) {
                                lastlost.video = lost.video;
                                lastrecv.video = recv.video;
                                recv.video = packetsrecv;
                                lost.video = packetslost;
                            } else {
                                lastlost.audio = lost.audio;
                                lastrecv.audio = recv.audio;
                                recv.audio = packetsrecv;
                                lost.audio = packetslost;
                            }
                        }
                    }
                }
                delta.audio = recv.audio - lastrecv.audio;
                delta.video = recv.video - lastrecv.video;
                loss.audio = (delta.audio > 0) ? Math.ceil(100 * (lost.audio - lastlost.audio) / delta.audio) : 0;
                loss.video = (delta.video > 0) ? Math.ceil(100 * (lost.video - lastlost.video) / delta.video) : 0;
                $(document).trigger('packetloss.jingle', [self.sid, loss]);
            });
        }
    }, interval || 3000);
    return this.statsinterval;
};

JingleSessionPC.onJingleError = function (session, error)
{
    console.error("Jingle error", error);
};

JingleSessionPC.onJingleFatalError = function (session, error)
{
    this.service.sessionTerminated = true;
    this.connection.emuc.doLeave();
    this.eventEmitter.emit(XMPPEvents.CONFERENCE_SETUP_FAILED);
    this.eventEmitter.emit(XMPPEvents.JINGLE_FATAL_ERROR, session, error);
};

JingleSessionPC.prototype.setLocalDescription = function () {
    var self = this;
    var newssrcs = [];
    var session = transform.parse(this.peerconnection.localDescription.sdp);
    session.media.forEach(function (media) {

        if (media.ssrcs && media.ssrcs.length > 0) {
            // TODO(gp) maybe exclude FID streams?
            media.ssrcs.forEach(function (ssrc) {
                if (ssrc.attribute !== 'cname') {
                    return;
                }
                newssrcs.push({
                    'ssrc': ssrc.id,
                    'type': media.type
                });
            });
        }
        else if(self.localStreamsSSRC && self.localStreamsSSRC[media.type])
        {
            newssrcs.push({
                'ssrc': self.localStreamsSSRC[media.type],
                'type': media.type
            });
        }

    });

    console.log('new ssrcs', newssrcs);

    // Bind us as local SSRCs owner
    if (newssrcs.length > 0) {
        for (var i = 1; i <= newssrcs.length; i ++) {
            var ssrc = newssrcs[i-1].ssrc;
            var myJid = self.connection.emuc.myroomjid;
            self.ssrcOwners[ssrc] = myJid;
        }
    }
};

// an attempt to work around https://github.com/jitsi/jitmeet/issues/32
// TODO: is this hack (along with the XMPPEvent-s used only for it) still needed
// now that we announce an SSRC for receive-only streams?
function sendKeyframe(pc) {
    console.log('sendkeyframe', pc.iceConnectionState);
    if (pc.iceConnectionState !== 'connected') return; // safe...
    pc.setRemoteDescription(
        pc.remoteDescription,
        function () {
            pc.createAnswer(
                function (modifiedAnswer) {
                    pc.setLocalDescription(
                        modifiedAnswer,
                        function () {
                            // noop
                        },
                        function (error) {
                            console.log('triggerKeyframe setLocalDescription failed', error);
                            eventEmitter.emit(XMPPEvents.SET_LOCAL_DESCRIPTION_ERROR);
                        }
                    );
                },
                function (error) {
                    console.log('triggerKeyframe createAnswer failed', error);
                    eventEmitter.emit(XMPPEvents.CREATE_ANSWER_ERROR);
                }
            );
        },
        function (error) {
            console.log('triggerKeyframe setRemoteDescription failed', error);
            eventEmitter.emit(XMPPEvents.SET_REMOTE_DESCRIPTION_ERROR);
        }
    );
}


JingleSessionPC.prototype.remoteStreamAdded = function (data, times) {
    var self = this;
    var thessrc;
    var streamId = APP.RTC.getStreamID(data.stream);

    // look up an associated JID for a stream id
    if (!streamId) {
        console.error("No stream ID for", data.stream);
    } else if (streamId && streamId.indexOf('mixedmslabel') === -1) {
        // look only at a=ssrc: and _not_ at a=ssrc-group: lines

        var ssrclines
            = SDPUtil.find_lines(this.peerconnection.remoteDescription.sdp, 'a=ssrc:');
        ssrclines = ssrclines.filter(function (line) {
            // NOTE(gp) previously we filtered on the mslabel, but that property
            // is not always present.
            // return line.indexOf('mslabel:' + data.stream.label) !== -1;

            if (RTCBrowserType.isTemasysPluginUsed()) {
                return ((line.indexOf('mslabel:' + streamId) !== -1));
            } else {
                return ((line.indexOf('msid:' + streamId) !== -1));
            }
        });
        if (ssrclines.length) {
            thessrc = ssrclines[0].substring(7).split(' ')[0];

            if (!self.ssrcOwners[thessrc]) {
                console.error("No SSRC owner known for: " + thessrc);
                return;
            }
            data.peerjid = self.ssrcOwners[thessrc];
            console.log('associated jid', self.ssrcOwners[thessrc]);
        } else {
            console.error("No SSRC lines for ", streamId);
        }
    }

    APP.RTC.createRemoteStream(data, this.sid, thessrc);

    var isVideo = data.stream.getVideoTracks().length > 0;
    // an attempt to work around https://github.com/jitsi/jitmeet/issues/32
    // TODO: is this hack still needed now that we announce an SSRC for
    // receive-only streams?
    if (isVideo &&
        data.peerjid && this.peerjid === data.peerjid &&
        data.stream.getVideoTracks().length === 0 &&
        APP.RTC.localVideo.getTracks().length > 0) {
        window.setTimeout(function () {
            sendKeyframe(self.peerconnection);
        }, 3000);
    }
};

module.exports = JingleSessionPC;