fix(video-quality) Fixes an issue where outbound resolution can be stuck at wrong resolution.

The calls to RTCRtpSender.setParameters() are all chained and the current maxHeight is set after the call to setParameters is resolved. If there is another call made to setParameters before the previous one resolves, we can end up passing the wrong maxHeight resulting in the client getting stuck at an unexpected resolution. This issue can be reproduced sometimes  when the users are moving across the main and breakout rooms. TPC.setVideoCodecs() ends up pushing a wrong maxHeight for update when the previous call to setParameters hasn't resolved yet.

Author: jallamsetty1

modules/RTC/TraceablePeerConnection.js

@@ -2057,10 +2057,10 @@ TraceablePeerConnection.prototype.setSenderVideoConstraints = function(frameHeig
     }
     const sourceName = localVideoTrack.getSourceName();
 
+    this._senderMaxHeights.set(sourceName, frameHeight);
+
     // Ignore sender constraints if the video track is muted.
     if (localVideoTrack.isMuted()) {
-        this._senderMaxHeights.set(sourceName, frameHeight);
-
         return Promise.resolve();
     }
 
@@ -2125,7 +2125,6 @@ TraceablePeerConnection.prototype._updateVideoSenderEncodings = function(frameHe
     let bitrates = this.tpcUtils.calculateEncodingsBitrates(localVideoTrack, codec, frameHeight);
     const scalabilityModes = this.tpcUtils.calculateEncodingsScalabilityMode(localVideoTrack, codec, frameHeight);
     let scaleFactors = this.tpcUtils.calculateEncodingsScaleFactor(localVideoTrack, codec, frameHeight);
-    const sourceName = localVideoTrack.getSourceName();
     let needsUpdate = false;
 
     // Do not configure 'scaleResolutionDownBy' and 'maxBitrate' for encoders running in VP9 legacy K-SVC mode since
@@ -2197,15 +2196,12 @@ TraceablePeerConnection.prototype._updateVideoSenderEncodings = function(frameHe
     }
 
     if (!needsUpdate) {
-        this._senderMaxHeights.set(sourceName, frameHeight);
-
         return Promise.resolve();
     }
 
     logger.info(`${this} setting max height=${frameHeight},encodings=${JSON.stringify(parameters.encodings)}`);
 
     return videoSender.setParameters(parameters).then(() => {
-        this._senderMaxHeights.set(sourceName, frameHeight);
         localVideoTrack.maxEnabledResolution = frameHeight;
         this.eventEmitter.emit(RTCEvents.LOCAL_TRACK_MAX_ENABLED_RESOLUTION_CHANGED, localVideoTrack);
     });