jiti-meet/simulcast.js

674 lines
22 KiB
JavaScript

/*jslint plusplus: true */
/*jslint nomen: true*/
/**
* Created by gp on 11/08/14.
*/
function Simulcast() {
"use strict";
// TODO(gp) split the Simulcast class in two classes : NativeSimulcast and ClassicSimulcast.
this.debugLvl = 1;
}
(function () {
"use strict";
// global state for all transformers.
var localExplosionMap = {}, localVideoSourceCache, emptyCompoundIndex,
remoteMaps = {
msid2Quality: {},
ssrc2Msid: {},
receivingVideoStreams: {}
}, localMaps = {
msids: [],
msid2ssrc: {}
};
Simulcast.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();
};
}());
Simulcast.prototype._cacheVideoSources = function (lines) {
localVideoSourceCache = this._getVideoSources(lines);
};
Simulcast.prototype._restoreVideoSources = function (lines) {
this._replaceVideoSources(lines, localVideoSourceCache);
};
Simulcast.prototype._replaceVideoSources = function (lines, videoSources) {
var i, inVideo = false, index = -1, howMany = 0;
if (this.debugLvl) {
console.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));
};
Simulcast.prototype._getVideoSources = function (lines) {
var i, inVideo = false, sb = [];
if (this.debugLvl) {
console.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;
};
Simulcast.prototype._parseMedia = function (lines, mediatypes) {
var i, res = [], type, cur_media, idx, ssrcs, cur_ssrc, ssrc,
ssrc_attribute, group, semantics, skip;
if (this.debugLvl) {
console.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, 8);
}
}
return res;
};
// Returns a random integer between min (included) and max (excluded)
// Using Math.round() will give you a non-uniform distribution!
Simulcast.prototype._generateRandomSSRC = function () {
var min = 0, max = 0xffffffff;
return Math.floor(Math.random() * (max - min)) + min;
};
function CompoundIndex(obj) {
if (obj !== undefined) {
this.row = obj.row;
this.column = obj.column;
}
}
emptyCompoundIndex = new CompoundIndex();
Simulcast.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 new CompoundIndex({row: i, column: idx});
}
}
return emptyCompoundIndex;
};
Simulcast.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);
}
}
};
Simulcast.prototype._explodeLocalSimulcastSources = function (lines) {
var sb, msid, sid, tid, videoSources, self;
if (this.debugLvl) {
console.info('Exploding local video sources...');
}
videoSources = this._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 (localExplosionMap[ssrc]) {
// .. either from the explosion map..
msid = 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(' ');
localExplosionMap[ssrc] = msid;
}
// Assign it to the source object.
videoSources.sources[ssrc].msid = msid;
// TODO(gp) Change the msid of associated sources.
});
}
});
}
sb = this._compileVideoSources(videoSources);
this._replaceVideoSources(lines, sb);
};
Simulcast.prototype._groupLocalVideoSources = function (lines) {
var sb, videoSources, ssrcs = [], ssrc;
if (this.debugLvl) {
console.info('Grouping local video sources...');
}
videoSources = this._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.
localMaps.msid2ssrc[videoSources.sources[ssrc].msid.split(' ')[1]] = ssrc;
}
// TODO(gp) add only "free" sources.
localMaps.msids.forEach(function (msid) {
ssrcs.push(localMaps.msid2ssrc[msid]);
});
if (!videoSources.groups) {
videoSources.groups = [];
}
videoSources.groups.push({
'semantics': 'SIM',
'ssrcs': ssrcs
});
sb = this._compileVideoSources(videoSources);
this._replaceVideoSources(lines, sb);
};
Simulcast.prototype._appendSimulcastGroup = function (lines) {
var videoSources, ssrcGroup, simSSRC, numOfSubs = 3, i, sb, msid;
if (this.debugLvl) {
console.info('Appending simulcast group...');
}
// Get the primary SSRC information.
videoSources = this._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);
sb.splice.apply(sb, [sb.length, 0].concat(
[["a=ssrc:", simSSRC, " cname:", videoSources.base.cname].join(''),
["a=ssrc:", simSSRC, " msid:", videoSources.base.msid].join('')]
));
if (this.debugLvl) {
console.info(['Generated substream ', i, ' with SSRC ', simSSRC, '.'].join(''));
}
}
// Add the group sim layers.
sb.splice(0, 0, ssrcGroup.join(' '))
this._replaceVideoSources(lines, sb);
};
// Does the actual patching.
Simulcast.prototype._ensureSimulcastGroup = function (lines) {
if (this.debugLvl) {
console.info('Ensuring simulcast group...');
}
if (this._indexOfArray('a=ssrc-group:SIM', lines) === emptyCompoundIndex) {
this._appendSimulcastGroup(lines);
this._cacheVideoSources(lines);
} else {
// verify that the ssrcs participating in the SIM group are present
// in the SDP (needed for presence).
this._restoreVideoSources(lines);
}
};
Simulcast.prototype._ensureGoogConference = function (lines) {
var sb;
if (this.debugLvl) {
console.info('Ensuring x-google-conference flag...')
}
if (this._indexOfArray('a=x-google-flag:conference', lines) === emptyCompoundIndex) {
// Add the google conference flag
sb = this._getVideoSources(lines);
sb = ['a=x-google-flag:conference'].concat(sb);
this._replaceVideoSources(lines, sb);
}
};
Simulcast.prototype._compileVideoSources = function (videoSources) {
var sb = [], ssrc, addedSSRCs = [];
if (this.debugLvl) {
console.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;
};
Simulcast.prototype.transformAnswer = function (desc) {
if (config.enableSimulcast && config.useNativeSimulcast) {
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')
});
if (this.debugLvl && this.debugLvl > 1) {
console.info('Transformed answer');
console.info(desc.sdp);
}
}
return desc;
};
Simulcast.prototype.makeLocalDescriptionPublic = function (desc) {
var sb;
if (!desc || desc == null)
return desc;
if (config.enableSimulcast) {
if (config.useNativeSimulcast) {
sb = desc.sdp.split('\r\n');
this._explodeLocalSimulcastSources(sb);
desc = new RTCSessionDescription({
type: desc.type,
sdp: sb.join('\r\n')
});
if (this.debugLvl && this.debugLvl > 1) {
console.info('Exploded local video sources');
console.info(desc.sdp);
}
} else {
sb = desc.sdp.split('\r\n');
this._groupLocalVideoSources(sb);
desc = new RTCSessionDescription({
type: desc.type,
sdp: sb.join('\r\n')
});
if (this.debugLvl && this.debugLvl > 1) {
console.info('Grouped local video sources');
console.info(desc.sdp);
}
}
}
return desc;
};
Simulcast.prototype._ensureOrder = function (lines) {
var videoSources, sb;
videoSources = this._parseMedia(lines, ['video'])[0];
sb = this._compileVideoSources(videoSources);
this._replaceVideoSources(lines, sb);
};
Simulcast.prototype.transformBridgeDescription = function (desc) {
if (config.enableSimulcast && config.useNativeSimulcast) {
var sb = desc.sdp.split('\r\n');
this._ensureGoogConference(sb);
desc = new RTCSessionDescription({
type: desc.type,
sdp: sb.join('\r\n')
});
if (this.debugLvl && this.debugLvl > 1) {
console.info('Transformed bridge description');
console.info(desc.sdp);
}
}
return desc;
};
Simulcast.prototype._updateRemoteMaps = function (lines) {
var remoteVideoSources = this._parseMedia(lines, ['video'])[0], videoSource, quality;
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];
remoteMaps.msid2Quality[videoSource.msid] = quality++;
remoteMaps.ssrc2Msid[videoSource.ssrc] = videoSource.msid;
});
}
});
}
};
Simulcast.prototype.transformLocalDescription = function (desc) {
if (config.enableSimulcast && !config.useNativeSimulcast) {
var sb = desc.sdp.split('\r\n');
this._removeSimulcastGroup(sb);
desc = new RTCSessionDescription({
type: desc.type,
sdp: sb.join('\r\n')
});
if (this.debugLvl && this.debugLvl > 1) {
console.info('Transformed local description');
console.info(desc.sdp);
}
}
return desc;
};
Simulcast.prototype.transformRemoteDescription = function (desc) {
if (config.enableSimulcast) {
var sb = desc.sdp.split('\r\n');
this._updateRemoteMaps(sb);
this._removeSimulcastGroup(sb); // NOTE(gp) this needs to be called after updateRemoteMaps!
this._ensureGoogConference(sb);
desc = new RTCSessionDescription({
type: desc.type,
sdp: sb.join('\r\n')
});
if (this.debugLvl && this.debugLvl > 1) {
console.info('Transformed remote description');
console.info(desc.sdp);
}
}
return desc;
};
Simulcast.prototype.setReceivingVideoStream = function (ssrc) {
var receivingTrack = remoteMaps.ssrc2Msid[ssrc],
msidParts = receivingTrack.split(' ');
remoteMaps.receivingVideoStreams[msidParts[0]] = msidParts[1];
};
Simulcast.prototype.getReceivingVideoStream = function (stream) {
var tracks, track, i, electedTrack, msid, quality = 1, receivingTrackId;
if (config.enableSimulcast) {
if (remoteMaps.receivingVideoStreams[stream.id])
{
receivingTrackId = remoteMaps.receivingVideoStreams[stream.id];
tracks = stream.getVideoTracks();
for (i = 0; i < tracks.length; i++) {
if (receivingTrackId === tracks[i].id) {
electedTrack = tracks[i];
break;
}
}
}
if (!electedTrack) {
tracks = stream.getVideoTracks();
for (i = 0; i < tracks.length; i++) {
track = tracks[i];
msid = [stream.id, track.id].join(' ');
if (remoteMaps.msid2Quality[msid] === quality) {
electedTrack = track;
break;
}
}
}
}
return (electedTrack)
? new webkitMediaStream([electedTrack])
: stream;
};
Simulcast.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
}
}
};
if (config.enableSimulcast && !config.useNativeSimulcast) {
// NOTE(gp) if we request the lq stream first webkitGetUserMedia fails randomly. Tested with Chrome 37.
navigator.webkitGetUserMedia(constraints, function (hqStream) {
// reset local maps.
localMaps.msids = [];
localMaps.msid2ssrc = {};
// add hq trackid to local map
localMaps.msids.push(hqStream.getVideoTracks()[0].id);
navigator.webkitGetUserMedia(lqConstraints, function (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
localMaps.msids.splice(0, 0, lqStream.getVideoTracks()[0].id);
hqStream.addTrack(lqStream.getVideoTracks()[0]);
success(hqStream);
}, err);
}, err);
} else {
// There's nothing special to do for native simulcast, so just do a normal GUM.
navigator.webkitGetUserMedia(constraints, function (hqStream) {
// reset local maps.
localMaps.msids = [];
localMaps.msid2ssrc = {};
// add hq stream to local map
localMaps.msids.push(hqStream.getVideoTracks()[0].id);
success(hqStream);
}, err);
}
};
Simulcast.prototype.getRemoteVideoStreamIdBySSRC = function (primarySSRC) {
return remoteMaps.ssrc2Msid[primarySSRC];
};
Simulcast.prototype.parseMedia = function (desc, mediatypes) {
var lines = desc.sdp.split('\r\n');
return this._parseMedia(lines, mediatypes);
};
}());