fix: Implement the encodings workaround only on Safari.

Explicitly check if all the encodings report the same scaleResolutionDownBy value before trying to ensure they match the expected values. This makes Chrome VP9 work again.

modules/RTC/TPCUtils.js

@@ -3,7 +3,6 @@ import transform from 'sdp-transform';
 
 import * as MediaType from '../../service/RTC/MediaType';
 import RTCEvents from '../../service/RTC/RTCEvents';
-import VideoType from '../../service/RTC/VideoType';
 import browser from '../browser';
 
 const logger = getLogger(__filename);
@@ -447,20 +446,18 @@ export class TPCUtils {
      * @returns {void}
      */
     updateEncodingsResolution(parameters) {
-        const localVideoTrack = this.pc.getLocalVideoTrack();
-
-        // Ignore desktop and non-simulcast tracks.
-        if (!(parameters
-            && parameters.encodings
-            && Array.isArray(parameters.encodings)
-            && this.pc.isSimulcastOn()
-            && localVideoTrack
-            && localVideoTrack.videoType !== VideoType.DESKTOP)) {
+        if (!(browser.isSafari() && parameters.encodings && Array.isArray(parameters.encodings))) {
             return;
         }
-
-        parameters.encodings.forEach((encoding, idx) => {
-            encoding.scaleResolutionDownBy = this.localStreamEncodingsConfig[idx].scaleResolutionDownBy;
-        });
+        const allEqualEncodings
+            = encodings => encodings.every(encoding => typeof encoding.scaleResolutionDownBy !== 'undefined'
+                && encoding.scaleResolutionDownBy === encodings[0].scaleResolutionDownBy);
+
+        // Implement the workaround only when all the encodings report the same resolution.
+        if (allEqualEncodings(parameters.encodings)) {
+            parameters.encodings.forEach((encoding, idx) => {
+                encoding.scaleResolutionDownBy = this.localStreamEncodingsConfig[idx].scaleResolutionDownBy;
+            });
+        }
     }
 }