mirror of https://github.com/jitsi/jitsi-meet
pull/448/head
781
George Politis
10 years ago
parent
8ec90ea675
commit
dc07fd733f
@ -1,271 +0,0 @@ |
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/* global $ */ |
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|
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/* |
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Here we do modifications of local video SSRCs. There are 2 situations we have |
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to handle: |
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|
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1. We generate SSRC for local recvonly video stream. This is the case when we |
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have no local camera and it is not generated automatically, but SSRC=1 is |
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used implicitly. If that happens RTCP packets will be dropped by the JVB |
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and we won't be able to request video key frames correctly. |
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|
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2. A hack to re-use SSRC of the first video stream for any new stream created |
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in future. It turned out that Chrome may keep on using the SSRC of removed |
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video stream in RTCP even though a new one has been created. So we just |
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want to avoid that by re-using it. Jingle 'source-remove'/'source-add' |
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notifications are blocked once first video SSRC is advertised to the focus. |
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What this hack does: |
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1. Stores the SSRC of the first video stream created by |
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a) scanning Jingle session-accept/session-invite for existing video SSRC |
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b) watching for 'source-add' for new video stream if it has not been |
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created in step a) |
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2. Exposes method 'mungeLocalVideoSSRC' which replaces any new video SSRC with |
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the stored one. It is called by 'TracablePeerConnection' before local SDP is |
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returned to the other parts of the application. |
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3. Scans 'source-remove'/'source-add' notifications for stored video SSRC and |
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blocks those notifications. This makes Jicofo and all participants think |
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that it exists all the time even if the video stream has been removed or |
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replaced locally. Thanks to that there is no additional signaling activity |
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on video mute or when switching to the desktop stream. |
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*/ |
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|
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var SDP = require('./SDP'); |
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var RTCBrowserType = require('../RTC/RTCBrowserType'); |
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|
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/** |
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* The hack is enabled on all browsers except FF by default |
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* FIXME finish the hack once removeStream method is implemented in FF |
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* @type {boolean} |
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*/ |
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var isEnabled = !RTCBrowserType.isFirefox(); |
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|
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/** |
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* Stored SSRC of local video stream. |
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*/ |
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var localVideoSSRC; |
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|
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/** |
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* SSRC used for recvonly video stream when we have no local camera. |
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* This is in order to tell Chrome what SSRC should be used in RTCP requests |
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* instead of 1. |
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*/ |
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var localRecvOnlySSRC; |
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|
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/** |
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* cname for <tt>localRecvOnlySSRC</tt> |
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*/ |
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var localRecvOnlyCName; |
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|
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/** |
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* Method removes <source> element which describes <tt>localVideoSSRC</tt> |
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* from given Jingle IQ. |
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* @param modifyIq 'source-add' or 'source-remove' Jingle IQ. |
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* @param actionName display name of the action which will be printed in log |
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* messages. |
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* @returns {*} modified Jingle IQ, so that it does not contain <source> element |
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* corresponding to <tt>localVideoSSRC</tt> or <tt>null</tt> if no |
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* other SSRCs left to be signaled after removing it. |
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*/ |
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var filterOutSource = function (modifyIq, actionName) { |
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var modifyIqTree = $(modifyIq.tree()); |
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if (!localVideoSSRC) |
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return modifyIqTree[0]; |
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var videoSSRC = modifyIqTree.find( |
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'>jingle>content[name="video"]' + |
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'>description>source[ssrc="' + localVideoSSRC + '"]'); |
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if (!videoSSRC.length) { |
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return modifyIqTree[0]; |
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} |
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console.info( |
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'Blocking ' + actionName + ' for local video SSRC: ' + localVideoSSRC); |
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videoSSRC.remove(); |
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// Check if any sources still left to be added/removed
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if (modifyIqTree.find('>jingle>content>description>source').length) { |
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return modifyIqTree[0]; |
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} else { |
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return null; |
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} |
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}; |
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|
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/** |
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* Scans given Jingle IQ for video SSRC and stores it. |
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* @param jingleIq the Jingle IQ to be scanned for video SSRC. |
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*/ |
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var storeLocalVideoSSRC = function (jingleIq) { |
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var videoSSRCs = |
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$(jingleIq.tree()) |
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.find('>jingle>content[name="video"]>description>source'); |
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videoSSRCs.each(function (idx, ssrcElem) { |
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if (localVideoSSRC) |
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return; |
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// We consider SSRC real only if it has msid attribute
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// recvonly streams in FF do not have it as well as local SSRCs
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// we generate for recvonly streams in Chrome
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var ssrSel = $(ssrcElem); |
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var msid = ssrSel.find('>parameter[name="msid"]'); |
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if (msid.length) { |
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var ssrcVal = ssrSel.attr('ssrc'); |
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if (ssrcVal) { |
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localVideoSSRC = ssrcVal; |
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console.info('Stored local video SSRC' + |
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' for future re-use: ' + localVideoSSRC); |
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} |
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} |
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}); |
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}; |
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/** |
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* Generates new SSRC for local video recvonly stream. |
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* FIXME what about eventual SSRC collision ? |
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*/ |
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function generateRecvonlySSRC() { |
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//
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localRecvOnlySSRC = |
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localVideoSSRC ? |
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localVideoSSRC : Math.random().toString(10).substring(2, 11); |
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localRecvOnlyCName = |
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Math.random().toString(36).substring(2); |
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console.info( |
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"Generated local recvonly SSRC: " + localRecvOnlySSRC + |
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", cname: " + localRecvOnlyCName); |
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} |
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var LocalSSRCReplacement = { |
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/** |
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* Method must be called before 'session-initiate' or 'session-invite' is |
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* sent. Scans the IQ for local video SSRC and stores it if detected. |
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* |
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* @param sessionInit our 'session-initiate' or 'session-accept' Jingle IQ |
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* which will be scanned for local video SSRC. |
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*/ |
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processSessionInit: function (sessionInit) { |
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if (!isEnabled) |
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return; |
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if (localVideoSSRC) { |
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console.error("Local SSRC stored already: " + localVideoSSRC); |
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return; |
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} |
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storeLocalVideoSSRC(sessionInit); |
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}, |
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/** |
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* If we have local video SSRC stored searched given |
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* <tt>localDescription</tt> for video SSRC and makes sure it is replaced |
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* with the stored one. |
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* @param localDescription local description object that will have local |
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* video SSRC replaced with the stored one |
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* @returns modified <tt>localDescription</tt> object. |
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*/ |
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mungeLocalVideoSSRC: function (localDescription) { |
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if (!isEnabled) |
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return localDescription; |
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if (!localDescription) { |
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console.warn("localDescription is null or undefined"); |
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return localDescription; |
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} |
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// IF we have local video SSRC stored make sure it is replaced
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// with old SSRC
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var sdp = new SDP(localDescription.sdp); |
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if (sdp.media.length < 2) |
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return; |
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if (localVideoSSRC && sdp.media[1].indexOf("a=ssrc:") !== -1 && |
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!sdp.containsSSRC(localVideoSSRC)) { |
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console.info("Does not contain: " |
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+ localVideoSSRC + "---" + sdp.media[1]); |
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// Get new video SSRC
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var map = sdp.getMediaSsrcMap(); |
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var videoPart = map[1]; |
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var videoSSRCs = videoPart.ssrcs; |
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var newSSRC = Object.keys(videoSSRCs)[0]; |
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console.info( |
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"Replacing new video SSRC: " + newSSRC + |
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" with " + localVideoSSRC); |
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localDescription.sdp = |
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sdp.raw.replace( |
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new RegExp('a=ssrc:' + newSSRC, 'g'), |
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'a=ssrc:' + localVideoSSRC); |
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} |
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else if (sdp.media[1].indexOf('a=ssrc:') === -1 && |
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sdp.media[1].indexOf('a=recvonly') !== -1) { |
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// Make sure we have any SSRC for recvonly video stream
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if (!localRecvOnlySSRC) { |
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generateRecvonlySSRC(); |
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} |
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console.info('No SSRC in video recvonly stream' + |
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' - adding SSRC: ' + localRecvOnlySSRC); |
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sdp.media[1] += 'a=ssrc:' + localRecvOnlySSRC + |
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' cname:' + localRecvOnlyCName + '\r\n'; |
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localDescription.sdp = sdp.session + sdp.media.join(''); |
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} |
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return localDescription; |
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}, |
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/** |
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* Method must be called before 'source-add' notification is sent. In case |
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* we have local video SSRC advertised already it will be removed from the |
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* notification. If no other SSRCs are described by given IQ null will be |
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* returned which means that there is no point in sending the notification. |
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* @param sourceAdd 'source-add' Jingle IQ to be processed |
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* @returns modified 'source-add' IQ which can be sent to the focus or |
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* <tt>null</tt> if no notification shall be sent. It is no longer |
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* a Strophe IQ Builder instance, but DOM element tree. |
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*/ |
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processSourceAdd: function (sourceAdd) { |
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if (!isEnabled) |
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return sourceAdd; |
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if (!localVideoSSRC) { |
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// Store local SSRC if available
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storeLocalVideoSSRC(sourceAdd); |
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return sourceAdd; |
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} else { |
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return filterOutSource(sourceAdd, 'source-add'); |
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} |
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}, |
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/** |
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* Method must be called before 'source-remove' notification is sent. |
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* Removes local video SSRC from the notification. If there are no other |
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* SSRCs described in the given IQ <tt>null</tt> will be returned which |
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* means that there is no point in sending the notification. |
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* @param sourceRemove 'source-remove' Jingle IQ to be processed |
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* @returns modified 'source-remove' IQ which can be sent to the focus or |
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* <tt>null</tt> if no notification shall be sent. It is no longer |
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* a Strophe IQ Builder instance, but DOM element tree. |
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*/ |
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processSourceRemove: function (sourceRemove) { |
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if (!isEnabled) |
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return sourceRemove; |
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return filterOutSource(sourceRemove, 'source-remove'); |
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}, |
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/** |
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* Turns the hack on or off |
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* @param enabled <tt>true</tt> to enable the hack or <tt>false</tt> |
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* to disable it |
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*/ |
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setEnabled: function (enabled) { |
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isEnabled = enabled; |
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} |
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}; |
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module.exports = LocalSSRCReplacement; |
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