Add the codec information for peer connections if supported (Chrome).

This adds the 'codec' object to the RTP stats passed out of lib-jitsi-meet.

modules/statistics/RTPStatsCollector.js

@@ -38,6 +38,7 @@ KEYS_BY_BROWSER_TYPE[browsers.CHROME] = {
     'packetsLost': 'packetsLost',
     'bytesReceived': 'bytesReceived',
     'bytesSent': 'bytesSent',
+    'googCodecName': 'googCodecName',
     'googFrameHeightReceived': 'googFrameHeightReceived',
     'googFrameWidthReceived': 'googFrameWidthReceived',
     'googFrameHeightSent': 'googFrameHeightSent',
@@ -92,6 +93,7 @@ function SsrcStats() {
     };
     this.resolution = {};
     this.framerate = 0;
+    this.codec = '';
 }
 
 /**
@@ -137,6 +139,10 @@ SsrcStats.prototype.setFramerate = function(framerate) {
     this.framerate = framerate || 0;
 };
 
+SsrcStats.prototype.setCodec = function(codec) {
+    this.codec = codec || '';
+};
+
 /**
  *
  */
@@ -693,8 +699,18 @@ StatsCollector.prototype.processStatsReport = function() {
         } else {
             ssrcStats.setResolution(null);
         }
+
+        let codec;
+
+        // Try to get the codec for later reporting.
+        try {
+            codec = getStatValue(now, 'googCodecName') || '';
+        } catch (e) { /* not supported*/ }
+
+        ssrcStats.setCodec(codec);
     }
 
+
     this.eventEmitter.emit(
         StatisticsEvents.BYTE_SENT_STATS, this.peerconnection, byteSentStats);
 
@@ -718,10 +734,13 @@ StatsCollector.prototype._processAndEmitReport = function() {
     let bitrateUpload = 0;
     const resolutions = {};
     const framerates = {};
+    const codecs = {};
     let audioBitrateDownload = 0;
     let audioBitrateUpload = 0;
+    let audioCodec = '';
     let videoBitrateDownload = 0;
     let videoBitrateUpload = 0;
+    let videoCodec = '';
 
     for (const [ ssrc, ssrcStats ] of this.ssrc2stats) {
         // process packet loss stats
@@ -742,9 +761,11 @@ StatsCollector.prototype._processAndEmitReport = function() {
             if (track.isAudioTrack()) {
                 audioBitrateDownload += ssrcStats.bitrate.download;
                 audioBitrateUpload += ssrcStats.bitrate.upload;
+                audioCodec = ssrcStats.codec;
             } else {
                 videoBitrateDownload += ssrcStats.bitrate.download;
                 videoBitrateUpload += ssrcStats.bitrate.upload;
+                videoCodec = ssrcStats.codec;
             }
 
             const participantId = track.getParticipantId();
@@ -767,6 +788,18 @@ StatsCollector.prototype._processAndEmitReport = function() {
                     userFramerates[ssrc] = ssrcStats.framerate;
                     framerates[participantId] = userFramerates;
                 }
+                if (audioCodec.length && videoCodec.length) {
+                    const codecDesc = {
+                        'audio': audioCodec,
+                        'video': videoCodec
+                    };
+
+                    // Is there a reason this can't be done more directly?
+                    const userCodecs = codecs[participantId] || {};
+
+                    userCodecs[ssrc] = codecDesc;
+                    codecs[participantId] = userCodecs;
+                }
             } else {
                 logger.error(`No participant ID returned by ${track}`);
             }
@@ -833,6 +866,7 @@ StatsCollector.prototype._processAndEmitReport = function() {
             'packetLoss': this.conferenceStats.packetLoss,
             'resolution': resolutions,
             'framerate': framerates,
+            'codec': codecs,
             'transport': this.conferenceStats.transport,
             localAvgAudioLevels,
             avgAudioLevels