fix(TPC) Avoid applying constraints on desktop tracks if not needed. (#2246)

* fix(TPC) Avoid applying constraints on desktop tracks if not needed.
Ignore sender constraints if the client is already sending video of the requested resolution. For desktop tracks, max resolution will be the height of the window being captured irrespective of the height being requested by the peer. Therfore, check if the configured resolution is equal to the track height for all requested heights > 0.
Fixes an issue where the track addition fails because of setParameters failing on the video track. This is only seen the torture tests because this is very timing specific.

* squash: check correct scaleResolutionDownBy value for p2p conn.

modules/RTC/TPCUtils.js

@@ -373,9 +373,14 @@ export class TPCUtils {
         if (!parameters?.encodings?.length) {
             return maxHeight;
         }
-        for (const encoding of parameters.encodings) {
-            if (encoding.active) {
-                maxHeight = Math.max(maxHeight, height / encoding.scaleResolutionDownBy);
+        for (const encoding in parameters.encodings) {
+            if (parameters.encodings[encoding].active) {
+                const scaleResolutionDownBy
+                    = this.pc.isSimulcastOn()
+                        ? this._getVideoStreamEncodings(localVideoTrack.getVideoType())[encoding].scaleResolutionDownBy
+                        : parameters.encodings[encoding].scaleResolutionDownBy;
+
+                maxHeight = Math.max(maxHeight, height / scaleResolutionDownBy);
             }
         }
 

modules/RTC/TraceablePeerConnection.js

@@ -2560,21 +2560,33 @@ TraceablePeerConnection.prototype.setSenderVideoConstraints = function(frameHeig
     if (frameHeight < 0) {
         throw new Error(`Invalid frameHeight: ${frameHeight}`);
     }
+    if (!localVideoTrack) {
+        throw new Error('Local video track is missing');
+    }
     const sourceName = localVideoTrack.getSourceName();
 
-    this._senderMaxHeights.set(sourceName, frameHeight);
+    // Ignore sender constraints if the media on the peerconnection is suspended (jvb conn when p2p is currently active)
+    // or if the video track is muted.
+    if (!this.videoTransferActive || localVideoTrack.isMuted()) {
+        this._senderMaxHeights.set(sourceName, frameHeight);
 
-    // Ignore sender constraints for the following cases -
-    // 1. If the media on the peerconnection is suspended (jvb conn when p2p is currently active).
-    // 2. If the client is already sending video of the requested resolution.
-    if (!this.videoTransferActive || this.tpcUtils.getConfiguredEncodeResolution(localVideoTrack) === frameHeight) {
         return Promise.resolve();
     }
 
-    if (!localVideoTrack || localVideoTrack.isMuted()) {
+    const configuredResolution = this.tpcUtils.getConfiguredEncodeResolution(localVideoTrack);
+
+    // Ignore sender constraints if the client is already sending video of the requested resolution. Note that for
+    // screensharing sources, the max resolution will be the height of the window being captured irrespective of the
+    // height being requested by the peer.
+    if ((localVideoTrack.getVideoType() === VideoType.CAMERA && configuredResolution === frameHeight)
+        || (localVideoTrack.getVideoType() === VideoType.DESKTOP
+            && frameHeight > 0
+            && configuredResolution === localVideoTrack.getTrack()?.getSettings()?.height)) {
         return Promise.resolve();
     }
 
+    this._senderMaxHeights.set(sourceName, frameHeight);
+
     return this._updateVideoSenderParameters(this._updateVideoSenderEncodings(frameHeight, localVideoTrack));
 };