summary refs log tree commit diff
path: root/contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js
diff options
context:
space:
mode:
authorDavid Baker <dbkr@matrix.org>2014-12-02 12:01:30 +0000
committerDavid Baker <dbkr@matrix.org>2014-12-02 12:01:30 +0000
commit758052d7f841c6ac8331d6dd0b419bb249fe770b (patch)
treeefc24263fd48b5d778455d81e40a96df9c39b29e /contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js
parentMerge branch 'master' of github.com:matrix-org/synapse into develop (diff)
downloadsynapse-758052d7f841c6ac8331d6dd0b419bb249fe770b.tar.xz
Add non-working jitsi meet bridge
Diffstat (limited to 'contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js')
-rw-r--r--contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js712
1 files changed, 712 insertions, 0 deletions
diff --git a/contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js b/contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js
new file mode 100644
index 0000000000..e99dd7bf96
--- /dev/null
+++ b/contrib/jitsimeetbridge/unjingle/strophe.jingle.sdp.js
@@ -0,0 +1,712 @@
+/* jshint -W117 */
+// SDP STUFF
+function SDP(sdp) {
+    this.media = sdp.split('\r\nm=');
+    for (var i = 1; i < this.media.length; i++) {
+        this.media[i] = 'm=' + this.media[i];
+        if (i != this.media.length - 1) {
+            this.media[i] += '\r\n';
+        }
+    }
+    this.session = this.media.shift() + '\r\n';
+    this.raw = this.session + this.media.join('');
+}
+
+exports.SDP = SDP;
+
+var jsdom          = require("jsdom");
+var window = jsdom.jsdom().parentWindow;
+var $ = require('jquery')(window);
+
+var SDPUtil = require('./strophe.jingle.sdp.util.js').SDPUtil;
+
+/**
+ * Returns map of MediaChannel mapped per channel idx.
+ */
+SDP.prototype.getMediaSsrcMap = function() {
+    var self = this;
+    var media_ssrcs = {};
+    for (channelNum = 0; channelNum < self.media.length; channelNum++) {
+        modified = true;
+        tmp = SDPUtil.find_lines(self.media[channelNum], 'a=ssrc:');
+        var type = SDPUtil.parse_mid(SDPUtil.find_line(self.media[channelNum], 'a=mid:'));
+        var channel = new MediaChannel(channelNum, type);
+        media_ssrcs[channelNum] = channel;
+        tmp.forEach(function (line) {
+            var linessrc = line.substring(7).split(' ')[0];
+            // allocate new ChannelSsrc
+            if(!channel.ssrcs[linessrc]) {
+                channel.ssrcs[linessrc] = new ChannelSsrc(linessrc, type);
+            }
+            channel.ssrcs[linessrc].lines.push(line);
+        });
+        tmp = SDPUtil.find_lines(self.media[channelNum], 'a=ssrc-group:');
+        tmp.forEach(function(line){
+            var semantics = line.substr(0, idx).substr(13);
+            var ssrcs = line.substr(14 + semantics.length).split(' ');
+            if (ssrcs.length != 0) {
+                var ssrcGroup = new ChannelSsrcGroup(semantics, ssrcs);
+                channel.ssrcGroups.push(ssrcGroup);
+            }
+        });
+    }
+    return media_ssrcs;
+};
+/**
+ * Returns <tt>true</tt> if this SDP contains given SSRC.
+ * @param ssrc the ssrc to check.
+ * @returns {boolean} <tt>true</tt> if this SDP contains given SSRC.
+ */
+SDP.prototype.containsSSRC = function(ssrc) {
+    var channels = this.getMediaSsrcMap();
+    var contains = false;
+    Object.keys(channels).forEach(function(chNumber){
+        var channel = channels[chNumber];
+        //console.log("Check", channel, ssrc);
+        if(Object.keys(channel.ssrcs).indexOf(ssrc) != -1){
+            contains = true;
+        }
+    });
+    return contains;
+};
+
+/**
+ * Returns map of MediaChannel that contains only media not contained in <tt>otherSdp</tt>. Mapped by channel idx.
+ * @param otherSdp the other SDP to check ssrc with.
+ */
+SDP.prototype.getNewMedia = function(otherSdp) {
+
+    // this could be useful in Array.prototype.
+    function arrayEquals(array) {
+        // if the other array is a falsy value, return
+        if (!array)
+            return false;
+
+        // compare lengths - can save a lot of time
+        if (this.length != array.length)
+            return false;
+
+        for (var i = 0, l=this.length; i < l; i++) {
+            // Check if we have nested arrays
+            if (this[i] instanceof Array && array[i] instanceof Array) {
+                // recurse into the nested arrays
+                if (!this[i].equals(array[i]))
+                    return false;
+            }
+            else if (this[i] != array[i]) {
+                // Warning - two different object instances will never be equal: {x:20} != {x:20}
+                return false;
+            }
+        }
+        return true;
+    }
+
+    var myMedia = this.getMediaSsrcMap();
+    var othersMedia = otherSdp.getMediaSsrcMap();
+    var newMedia = {};
+    Object.keys(othersMedia).forEach(function(channelNum) {
+        var myChannel = myMedia[channelNum];
+        var othersChannel = othersMedia[channelNum];
+        if(!myChannel && othersChannel) {
+            // Add whole channel
+            newMedia[channelNum] = othersChannel;
+            return;
+        }
+        // Look for new ssrcs accross the channel
+        Object.keys(othersChannel.ssrcs).forEach(function(ssrc) {
+            if(Object.keys(myChannel.ssrcs).indexOf(ssrc) === -1) {
+                // Allocate channel if we've found ssrc that doesn't exist in our channel
+                if(!newMedia[channelNum]){
+                    newMedia[channelNum] = new MediaChannel(othersChannel.chNumber, othersChannel.mediaType);
+                }
+                newMedia[channelNum].ssrcs[ssrc] = othersChannel.ssrcs[ssrc];
+            }
+        });
+
+        // Look for new ssrc groups across the channels
+        othersChannel.ssrcGroups.forEach(function(otherSsrcGroup){
+
+            // try to match the other ssrc-group with an ssrc-group of ours
+            var matched = false;
+            for (var i = 0; i < myChannel.ssrcGroups.length; i++) {
+                var mySsrcGroup = myChannel.ssrcGroups[i];
+                if (otherSsrcGroup.semantics == mySsrcGroup.semantics
+                    && arrayEquals.apply(otherSsrcGroup.ssrcs, [mySsrcGroup.ssrcs])) {
+
+                    matched = true;
+                    break;
+                }
+            }
+
+            if (!matched) {
+                // Allocate channel if we've found an ssrc-group that doesn't
+                // exist in our channel
+
+                if(!newMedia[channelNum]){
+                    newMedia[channelNum] = new MediaChannel(othersChannel.chNumber, othersChannel.mediaType);
+                }
+                newMedia[channelNum].ssrcGroups.push(otherSsrcGroup);
+            }
+        });
+    });
+    return newMedia;
+};
+
+// remove iSAC and CN from SDP
+SDP.prototype.mangle = function () {
+    var i, j, mline, lines, rtpmap, newdesc;
+    for (i = 0; i < this.media.length; i++) {
+        lines = this.media[i].split('\r\n');
+        lines.pop(); // remove empty last element
+        mline = SDPUtil.parse_mline(lines.shift());
+        if (mline.media != 'audio')
+            continue;
+        newdesc = '';
+        mline.fmt.length = 0;
+        for (j = 0; j < lines.length; j++) {
+            if (lines[j].substr(0, 9) == 'a=rtpmap:') {
+                rtpmap = SDPUtil.parse_rtpmap(lines[j]);
+                if (rtpmap.name == 'CN' || rtpmap.name == 'ISAC')
+                    continue;
+                mline.fmt.push(rtpmap.id);
+                newdesc += lines[j] + '\r\n';
+            } else {
+                newdesc += lines[j] + '\r\n';
+            }
+        }
+        this.media[i] = SDPUtil.build_mline(mline) + '\r\n';
+        this.media[i] += newdesc;
+    }
+    this.raw = this.session + this.media.join('');
+};
+
+// remove lines matching prefix from session section
+SDP.prototype.removeSessionLines = function(prefix) {
+    var self = this;
+    var lines = SDPUtil.find_lines(this.session, prefix);
+    lines.forEach(function(line) {
+        self.session = self.session.replace(line + '\r\n', '');
+    });
+    this.raw = this.session + this.media.join('');
+    return lines;
+}
+// remove lines matching prefix from a media section specified by mediaindex
+// TODO: non-numeric mediaindex could match mid
+SDP.prototype.removeMediaLines = function(mediaindex, prefix) {
+    var self = this;
+    var lines = SDPUtil.find_lines(this.media[mediaindex], prefix);
+    lines.forEach(function(line) {
+        self.media[mediaindex] = self.media[mediaindex].replace(line + '\r\n', '');
+    });
+    this.raw = this.session + this.media.join('');
+    return lines;
+}
+
+// add content's to a jingle element
+SDP.prototype.toJingle = function (elem, thecreator) {
+    var i, j, k, mline, ssrc, rtpmap, tmp, line, lines;
+    var self = this;
+    // new bundle plan
+    if (SDPUtil.find_line(this.session, 'a=group:')) {
+        lines = SDPUtil.find_lines(this.session, 'a=group:');
+        for (i = 0; i < lines.length; i++) {
+            tmp = lines[i].split(' ');
+            var semantics = tmp.shift().substr(8);
+            elem.c('group', {xmlns: 'urn:xmpp:jingle:apps:grouping:0', semantics:semantics});
+            for (j = 0; j < tmp.length; j++) {
+                elem.c('content', {name: tmp[j]}).up();
+            }
+            elem.up();
+        }
+    }
+    // old bundle plan, to be removed
+    var bundle = [];
+    if (SDPUtil.find_line(this.session, 'a=group:BUNDLE')) {
+        bundle = SDPUtil.find_line(this.session, 'a=group:BUNDLE ').split(' ');
+        bundle.shift();
+    }
+    for (i = 0; i < this.media.length; i++) {
+        mline = SDPUtil.parse_mline(this.media[i].split('\r\n')[0]);
+        if (!(mline.media === 'audio' ||
+              mline.media === 'video' ||
+              mline.media === 'application'))
+        {
+            continue;
+        }
+        if (SDPUtil.find_line(this.media[i], 'a=ssrc:')) {
+            ssrc = SDPUtil.find_line(this.media[i], 'a=ssrc:').substring(7).split(' ')[0]; // take the first
+        } else {
+            ssrc = false;
+        }
+
+        elem.c('content', {creator: thecreator, name: mline.media});
+        if (SDPUtil.find_line(this.media[i], 'a=mid:')) {
+            // prefer identifier from a=mid if present
+            var mid = SDPUtil.parse_mid(SDPUtil.find_line(this.media[i], 'a=mid:'));
+            elem.attrs({ name: mid });
+
+            // old BUNDLE plan, to be removed
+            if (bundle.indexOf(mid) !== -1) {
+                elem.c('bundle', {xmlns: 'http://estos.de/ns/bundle'}).up();
+                bundle.splice(bundle.indexOf(mid), 1);
+            }
+        }
+
+        if (SDPUtil.find_line(this.media[i], 'a=rtpmap:').length)
+        {
+            elem.c('description',
+                {xmlns: 'urn:xmpp:jingle:apps:rtp:1',
+                    media: mline.media });
+            if (ssrc) {
+                elem.attrs({ssrc: ssrc});
+            }
+            for (j = 0; j < mline.fmt.length; j++) {
+                rtpmap = SDPUtil.find_line(this.media[i], 'a=rtpmap:' + mline.fmt[j]);
+                elem.c('payload-type', SDPUtil.parse_rtpmap(rtpmap));
+                // put any 'a=fmtp:' + mline.fmt[j] lines into <param name=foo value=bar/>
+                if (SDPUtil.find_line(this.media[i], 'a=fmtp:' + mline.fmt[j])) {
+                    tmp = SDPUtil.parse_fmtp(SDPUtil.find_line(this.media[i], 'a=fmtp:' + mline.fmt[j]));
+                    for (k = 0; k < tmp.length; k++) {
+                        elem.c('parameter', tmp[k]).up();
+                    }
+                }
+                this.RtcpFbToJingle(i, elem, mline.fmt[j]); // XEP-0293 -- map a=rtcp-fb
+
+                elem.up();
+            }
+            if (SDPUtil.find_line(this.media[i], 'a=crypto:', this.session)) {
+                elem.c('encryption', {required: 1});
+                var crypto = SDPUtil.find_lines(this.media[i], 'a=crypto:', this.session);
+                crypto.forEach(function(line) {
+                    elem.c('crypto', SDPUtil.parse_crypto(line)).up();
+                });
+                elem.up(); // end of encryption
+            }
+
+            if (ssrc) {
+                // new style mapping
+                elem.c('source', { ssrc: ssrc, xmlns: 'urn:xmpp:jingle:apps:rtp:ssma:0' });
+                // FIXME: group by ssrc and support multiple different ssrcs
+                var ssrclines = SDPUtil.find_lines(this.media[i], 'a=ssrc:');
+                ssrclines.forEach(function(line) {
+                    idx = line.indexOf(' ');
+                    var linessrc = line.substr(0, idx).substr(7);
+                    if (linessrc != ssrc) {
+                        elem.up();
+                        ssrc = linessrc;
+                        elem.c('source', { ssrc: ssrc, xmlns: 'urn:xmpp:jingle:apps:rtp:ssma:0' });
+                    }
+                    var kv = line.substr(idx + 1);
+                    elem.c('parameter');
+                    if (kv.indexOf(':') == -1) {
+                        elem.attrs({ name: kv });
+                    } else {
+                        elem.attrs({ name: kv.split(':', 2)[0] });
+                        elem.attrs({ value: kv.split(':', 2)[1] });
+                    }
+                    elem.up();
+                });
+                elem.up();
+
+                // old proprietary mapping, to be removed at some point
+                tmp = SDPUtil.parse_ssrc(this.media[i]);
+                tmp.xmlns = 'http://estos.de/ns/ssrc';
+                tmp.ssrc = ssrc;
+                elem.c('ssrc', tmp).up(); // ssrc is part of description
+
+                // XEP-0339 handle ssrc-group attributes
+                var ssrc_group_lines = SDPUtil.find_lines(this.media[i], 'a=ssrc-group:');
+                ssrc_group_lines.forEach(function(line) {
+                    idx = line.indexOf(' ');
+                    var semantics = line.substr(0, idx).substr(13);
+                    var ssrcs = line.substr(14 + semantics.length).split(' ');
+                    if (ssrcs.length != 0) {
+                        elem.c('ssrc-group', { semantics: semantics, xmlns: 'urn:xmpp:jingle:apps:rtp:ssma:0' });
+                        ssrcs.forEach(function(ssrc) {
+                            elem.c('source', { ssrc: ssrc })
+                                .up();
+                        });
+                        elem.up();
+                    }
+                });
+            }
+
+            if (SDPUtil.find_line(this.media[i], 'a=rtcp-mux')) {
+                elem.c('rtcp-mux').up();
+            }
+
+            // XEP-0293 -- map a=rtcp-fb:*
+            this.RtcpFbToJingle(i, elem, '*');
+
+            // XEP-0294
+            if (SDPUtil.find_line(this.media[i], 'a=extmap:')) {
+                lines = SDPUtil.find_lines(this.media[i], 'a=extmap:');
+                for (j = 0; j < lines.length; j++) {
+                    tmp = SDPUtil.parse_extmap(lines[j]);
+                    elem.c('rtp-hdrext', { xmlns: 'urn:xmpp:jingle:apps:rtp:rtp-hdrext:0',
+                        uri: tmp.uri,
+                        id: tmp.value });
+                    if (tmp.hasOwnProperty('direction')) {
+                        switch (tmp.direction) {
+                            case 'sendonly':
+                                elem.attrs({senders: 'responder'});
+                                break;
+                            case 'recvonly':
+                                elem.attrs({senders: 'initiator'});
+                                break;
+                            case 'sendrecv':
+                                elem.attrs({senders: 'both'});
+                                break;
+                            case 'inactive':
+                                elem.attrs({senders: 'none'});
+                                break;
+                        }
+                    }
+                    // TODO: handle params
+                    elem.up();
+                }
+            }
+            elem.up(); // end of description
+        }
+
+        // map ice-ufrag/pwd, dtls fingerprint, candidates
+        this.TransportToJingle(i, elem);
+
+        if (SDPUtil.find_line(this.media[i], 'a=sendrecv', this.session)) {
+            elem.attrs({senders: 'both'});
+        } else if (SDPUtil.find_line(this.media[i], 'a=sendonly', this.session)) {
+            elem.attrs({senders: 'initiator'});
+        } else if (SDPUtil.find_line(this.media[i], 'a=recvonly', this.session)) {
+            elem.attrs({senders: 'responder'});
+        } else if (SDPUtil.find_line(this.media[i], 'a=inactive', this.session)) {
+            elem.attrs({senders: 'none'});
+        }
+        if (mline.port == '0') {
+            // estos hack to reject an m-line
+            elem.attrs({senders: 'rejected'});
+        }
+        elem.up(); // end of content
+    }
+    elem.up();
+    return elem;
+};
+
+SDP.prototype.TransportToJingle = function (mediaindex, elem) {
+    var i = mediaindex;
+    var tmp;
+    var self = this;
+    elem.c('transport');
+
+    // XEP-0343 DTLS/SCTP
+    if (SDPUtil.find_line(this.media[mediaindex], 'a=sctpmap:').length)
+    {
+        var sctpmap = SDPUtil.find_line(
+            this.media[i], 'a=sctpmap:', self.session);
+        if (sctpmap)
+        {
+            var sctpAttrs = SDPUtil.parse_sctpmap(sctpmap);
+            elem.c('sctpmap',
+                {
+                    xmlns: 'urn:xmpp:jingle:transports:dtls-sctp:1',
+                    number: sctpAttrs[0], /* SCTP port */
+                    protocol: sctpAttrs[1], /* protocol */
+                });
+            // Optional stream count attribute
+            if (sctpAttrs.length > 2)
+                elem.attrs({ streams: sctpAttrs[2]});
+            elem.up();
+        }
+    }
+    // XEP-0320
+    var fingerprints = SDPUtil.find_lines(this.media[mediaindex], 'a=fingerprint:', this.session);
+    fingerprints.forEach(function(line) {
+        tmp = SDPUtil.parse_fingerprint(line);
+        tmp.xmlns = 'urn:xmpp:jingle:apps:dtls:0';
+        elem.c('fingerprint').t(tmp.fingerprint);
+        delete tmp.fingerprint;
+        line = SDPUtil.find_line(self.media[mediaindex], 'a=setup:', self.session);
+        if (line) {
+            tmp.setup = line.substr(8);
+        }
+        elem.attrs(tmp);
+        elem.up(); // end of fingerprint
+    });
+    tmp = SDPUtil.iceparams(this.media[mediaindex], this.session);
+    if (tmp) {
+        tmp.xmlns = 'urn:xmpp:jingle:transports:ice-udp:1';
+        elem.attrs(tmp);
+        // XEP-0176
+        if (SDPUtil.find_line(this.media[mediaindex], 'a=candidate:', this.session)) { // add any a=candidate lines
+            var lines = SDPUtil.find_lines(this.media[mediaindex], 'a=candidate:', this.session);
+            lines.forEach(function (line) {
+                elem.c('candidate', SDPUtil.candidateToJingle(line)).up();
+            });
+        }
+    }
+    elem.up(); // end of transport
+}
+
+SDP.prototype.RtcpFbToJingle = function (mediaindex, elem, payloadtype) { // XEP-0293
+    var lines = SDPUtil.find_lines(this.media[mediaindex], 'a=rtcp-fb:' + payloadtype);
+    lines.forEach(function (line) {
+        var tmp = SDPUtil.parse_rtcpfb(line);
+        if (tmp.type == 'trr-int') {
+            elem.c('rtcp-fb-trr-int', {xmlns: 'urn:xmpp:jingle:apps:rtp:rtcp-fb:0', value: tmp.params[0]});
+            elem.up();
+        } else {
+            elem.c('rtcp-fb', {xmlns: 'urn:xmpp:jingle:apps:rtp:rtcp-fb:0', type: tmp.type});
+            if (tmp.params.length > 0) {
+                elem.attrs({'subtype': tmp.params[0]});
+            }
+            elem.up();
+        }
+    });
+};
+
+SDP.prototype.RtcpFbFromJingle = function (elem, payloadtype) { // XEP-0293
+    var media = '';
+    var tmp = elem.find('>rtcp-fb-trr-int[xmlns="urn:xmpp:jingle:apps:rtp:rtcp-fb:0"]');
+    if (tmp.length) {
+        media += 'a=rtcp-fb:' + '*' + ' ' + 'trr-int' + ' ';
+        if (tmp.attr('value')) {
+            media += tmp.attr('value');
+        } else {
+            media += '0';
+        }
+        media += '\r\n';
+    }
+    tmp = elem.find('>rtcp-fb[xmlns="urn:xmpp:jingle:apps:rtp:rtcp-fb:0"]');
+    tmp.each(function () {
+        media += 'a=rtcp-fb:' + payloadtype + ' ' + $(this).attr('type');
+        if ($(this).attr('subtype')) {
+            media += ' ' + $(this).attr('subtype');
+        }
+        media += '\r\n';
+    });
+    return media;
+};
+
+// construct an SDP from a jingle stanza
+SDP.prototype.fromJingle = function (jingle) {
+    var self = this;
+    this.raw = 'v=0\r\n' +
+        'o=- ' + '1923518516' + ' 2 IN IP4 0.0.0.0\r\n' +// FIXME
+        's=-\r\n' +
+        't=0 0\r\n';
+    // http://tools.ietf.org/html/draft-ietf-mmusic-sdp-bundle-negotiation-04#section-8
+    if ($(jingle).find('>group[xmlns="urn:xmpp:jingle:apps:grouping:0"]').length) {
+        $(jingle).find('>group[xmlns="urn:xmpp:jingle:apps:grouping:0"]').each(function (idx, group) {
+            var contents = $(group).find('>content').map(function (idx, content) {
+                return content.getAttribute('name');
+            }).get();
+            if (contents.length > 0) {
+                self.raw += 'a=group:' + (group.getAttribute('semantics') || group.getAttribute('type')) + ' ' + contents.join(' ') + '\r\n';
+            }
+        });
+    } else if ($(jingle).find('>group[xmlns="urn:ietf:rfc:5888"]').length) {
+        // temporary namespace, not to be used. to be removed soon.
+        $(jingle).find('>group[xmlns="urn:ietf:rfc:5888"]').each(function (idx, group) {
+            var contents = $(group).find('>content').map(function (idx, content) {
+                return content.getAttribute('name');
+            }).get();
+            if (group.getAttribute('type') !== null && contents.length > 0) {
+                self.raw += 'a=group:' + group.getAttribute('type') + ' ' + contents.join(' ') + '\r\n';
+            }
+        });
+    } else {
+        // for backward compability, to be removed soon
+        // assume all contents are in the same bundle group, can be improved upon later
+        var bundle = $(jingle).find('>content').filter(function (idx, content) {
+            //elem.c('bundle', {xmlns:'http://estos.de/ns/bundle'});
+            return $(content).find('>bundle').length > 0;
+        }).map(function (idx, content) {
+                return content.getAttribute('name');
+            }).get();
+        if (bundle.length) {
+            this.raw += 'a=group:BUNDLE ' + bundle.join(' ') + '\r\n';
+        }
+    }
+
+    this.session = this.raw;
+    jingle.find('>content').each(function () {
+        var m = self.jingle2media($(this));
+        self.media.push(m);
+    });
+
+    // reconstruct msid-semantic -- apparently not necessary
+    /*
+     var msid = SDPUtil.parse_ssrc(this.raw);
+     if (msid.hasOwnProperty('mslabel')) {
+     this.session += "a=msid-semantic: WMS " + msid.mslabel + "\r\n";
+     }
+     */
+
+    this.raw = this.session + this.media.join('');
+};
+
+// translate a jingle content element into an an SDP media part
+SDP.prototype.jingle2media = function (content) {
+    var media = '',
+        desc = content.find('description'),
+        ssrc = desc.attr('ssrc'),
+        self = this,
+        tmp;
+    var sctp = content.find(
+        '>transport>sctpmap[xmlns="urn:xmpp:jingle:transports:dtls-sctp:1"]');
+
+    tmp = { media: desc.attr('media') };
+    tmp.port = '1';
+    if (content.attr('senders') == 'rejected') {
+        // estos hack to reject an m-line.
+        tmp.port = '0';
+    }
+    if (content.find('>transport>fingerprint').length || desc.find('encryption').length) {
+        if (sctp.length)
+            tmp.proto = 'DTLS/SCTP';
+        else
+            tmp.proto = 'RTP/SAVPF';
+    } else {
+        tmp.proto = 'RTP/AVPF';
+    }
+    if (!sctp.length)
+    {
+        tmp.fmt = desc.find('payload-type').map(
+            function () { return this.getAttribute('id'); }).get();
+        media += SDPUtil.build_mline(tmp) + '\r\n';
+    }
+    else
+    {
+        media += 'm=application 1 DTLS/SCTP ' + sctp.attr('number') + '\r\n';
+        media += 'a=sctpmap:' + sctp.attr('number') +
+            ' ' + sctp.attr('protocol');
+
+        var streamCount = sctp.attr('streams');
+        if (streamCount)
+            media += ' ' + streamCount + '\r\n';
+        else
+            media += '\r\n';
+    }
+
+    media += 'c=IN IP4 0.0.0.0\r\n';
+    if (!sctp.length)
+        media += 'a=rtcp:1 IN IP4 0.0.0.0\r\n';
+    //tmp = content.find('>transport[xmlns="urn:xmpp:jingle:transports:ice-udp:1"]');
+    tmp = content.find('>bundle>transport[xmlns="urn:xmpp:jingle:transports:ice-udp:1"]');
+    //console.log('transports: '+content.find('>transport[xmlns="urn:xmpp:jingle:transports:ice-udp:1"]').length);
+    //console.log('bundle.transports: '+content.find('>bundle>transport[xmlns="urn:xmpp:jingle:transports:ice-udp:1"]').length);
+    //console.log("tmp fingerprint: "+tmp.find('>fingerprint').innerHTML);
+    if (tmp.length) {
+        if (tmp.attr('ufrag')) {
+            media += SDPUtil.build_iceufrag(tmp.attr('ufrag')) + '\r\n';
+        }
+        if (tmp.attr('pwd')) {
+            media += SDPUtil.build_icepwd(tmp.attr('pwd')) + '\r\n';
+        }
+        tmp.find('>fingerprint').each(function () {
+            // FIXME: check namespace at some point
+            media += 'a=fingerprint:' + this.getAttribute('hash');
+            media += ' ' + $(this).text();
+            media += '\r\n';
+            //console.log("mline "+media);
+            if (this.getAttribute('setup')) {
+                media += 'a=setup:' + this.getAttribute('setup') + '\r\n';
+            }
+        });
+    }
+    switch (content.attr('senders')) {
+        case 'initiator':
+            media += 'a=sendonly\r\n';
+            break;
+        case 'responder':
+            media += 'a=recvonly\r\n';
+            break;
+        case 'none':
+            media += 'a=inactive\r\n';
+            break;
+        case 'both':
+            media += 'a=sendrecv\r\n';
+            break;
+    }
+    media += 'a=mid:' + content.attr('name') + '\r\n';
+    /*if (content.attr('name') == 'video') {
+        media += 'a=x-google-flag:conference' + '\r\n';
+    }*/
+
+    // <description><rtcp-mux/></description>
+    // see http://code.google.com/p/libjingle/issues/detail?id=309 -- no spec though
+    // and http://mail.jabber.org/pipermail/jingle/2011-December/001761.html
+    if (desc.find('rtcp-mux').length) {
+        media += 'a=rtcp-mux\r\n';
+    }
+
+    if (desc.find('encryption').length) {
+        desc.find('encryption>crypto').each(function () {
+            media += 'a=crypto:' + this.getAttribute('tag');
+            media += ' ' + this.getAttribute('crypto-suite');
+            media += ' ' + this.getAttribute('key-params');
+            if (this.getAttribute('session-params')) {
+                media += ' ' + this.getAttribute('session-params');
+            }
+            media += '\r\n';
+        });
+    }
+    desc.find('payload-type').each(function () {
+        media += SDPUtil.build_rtpmap(this) + '\r\n';
+        if ($(this).find('>parameter').length) {
+            media += 'a=fmtp:' + this.getAttribute('id') + ' ';
+            media += $(this).find('parameter').map(function () { return (this.getAttribute('name') ? (this.getAttribute('name') + '=') : '') + this.getAttribute('value'); }).get().join('; ');
+            media += '\r\n';
+        }
+        // xep-0293
+        media += self.RtcpFbFromJingle($(this), this.getAttribute('id'));
+    });
+
+    // xep-0293
+    media += self.RtcpFbFromJingle(desc, '*');
+
+    // xep-0294
+    tmp = desc.find('>rtp-hdrext[xmlns="urn:xmpp:jingle:apps:rtp:rtp-hdrext:0"]');
+    tmp.each(function () {
+        media += 'a=extmap:' + this.getAttribute('id') + ' ' + this.getAttribute('uri') + '\r\n';
+    });
+
+    content.find('>bundle>transport[xmlns="urn:xmpp:jingle:transports:ice-udp:1"]>candidate').each(function () {
+        media += SDPUtil.candidateFromJingle(this);
+    });
+
+    // XEP-0339 handle ssrc-group attributes
+    tmp = content.find('description>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 != 0) {
+            media += 'a=ssrc-group:' + semantics + ' ' + ssrcs.join(' ') + '\r\n';
+        }
+    });
+
+    tmp = content.find('description>source[xmlns="urn:xmpp:jingle:apps:rtp:ssma:0"]');
+    tmp.each(function () {
+        var ssrc = this.getAttribute('ssrc');
+        $(this).find('>parameter').each(function () {
+            media += 'a=ssrc:' + ssrc + ' ' + this.getAttribute('name');
+            if (this.getAttribute('value') && this.getAttribute('value').length)
+                media += ':' + this.getAttribute('value');
+            media += '\r\n';
+        });
+    });
+
+    if (tmp.length === 0) {
+        // fallback to proprietary mapping of a=ssrc lines
+        tmp = content.find('description>ssrc[xmlns="http://estos.de/ns/ssrc"]');
+        if (tmp.length) {
+            media += 'a=ssrc:' + ssrc + ' cname:' + tmp.attr('cname') + '\r\n';
+            media += 'a=ssrc:' + ssrc + ' msid:' + tmp.attr('msid') + '\r\n';
+            media += 'a=ssrc:' + ssrc + ' mslabel:' + tmp.attr('mslabel') + '\r\n';
+            media += 'a=ssrc:' + ssrc + ' label:' + tmp.attr('label') + '\r\n';
+        }
+    }
+    return media;
+};
+