Read capapbilites from RtcRTPReceiver instead of from sender (#1088)

* Read capapbilites from RtcRTPReceiver instead of from sender

* Create lovely-cups-tell.md

* Add comments

Author: lukasIO

.changeset/lovely-cups-tell.md

@@ -0,0 +1,5 @@
+---
+"livekit-client": patch
+---
+
+Read capapbilites from RtcRTPReceiver instead of from sender

src/room/RTCEngine.ts

@@ -669,12 +669,13 @@ export default class RTCEngine extends (EventEmitter as new () => TypedEventEmit
     kind: Track.Kind,
     videoCodec: VideoCodec,
   ) {
-    if (!('getCapabilities' in RTCRtpSender)) {
+    if (!('getCapabilities' in RTCRtpReceiver)) {
       return;
     }
-    const cap = RTCRtpSender.getCapabilities(kind);
+    // when setting codec preferences, the capabilites need to be read from the RTCRtpReceiver
+    const cap = RTCRtpReceiver.getCapabilities(kind);
     if (!cap) return;
-    this.log.debug('get sender capabilities', { ...this.logContext, cap });
+    this.log.debug('get receiver capabilities', { ...this.logContext, cap });
     const matched: RTCRtpCodecCapability[] = [];
     const partialMatched: RTCRtpCodecCapability[] = [];
     const unmatched: RTCRtpCodecCapability[] = [];