How to send and receive video/audio on a single peer connection?

[Johan-Liebert1]

I've been trying to both send and receive audio video on a single peer connection, but have been unable to get it working.

Was getting this error

9:42AM WRN logger.go:68 > Incoming unhandled RTCP ssrc(415870679), OnTrack will not be fired module=webrtc subsystem=pc
9:42AM ERR logger.go:77 > Incoming unhandled RTP ssrc(415870679), OnTrack will not be fired. mid RTP Extensions required for Simulcast module=webrtc subsystem=pc

Looked into the simulcast example, but couldn't resolve it.

My server sends audio and video to the client (the connections. AddTracks)
I also want to receive webcam feedback from the client

This is my function which creates a Peer

	configuration := webrtc.Configuration{
		SDPSemantics: webrtc.SDPSemanticsUnifiedPlanWithFallback,
	}
	if !manager.config.ICELite {
		configuration.ICEServers = manager.config.ICEServers
	}

	// Create new peer connection
	connection, err := manager.api.NewPeerConnection(configuration)
	if err != nil {
		return nil, err
	}

	dcs, dcErr := manager.HandleDataChannels(connection, id)
	if dcErr != nil {
		return nil, err
	}

	if _, err = connection.AddTransceiverFromKind(
		webrtc.RTPCodecTypeVideo,
		webrtc.RTPTransceiverInit{
			Direction: webrtc.RTPTransceiverDirectionRecvonly,
			// SendEncodings: []webrtc.RTPEncodingParameters{
			// 	webrtc.RTPEncodingParameters{
			// 		RTPCodingParameters: webrtc.RTPCodingParameters{},
			// 	},
			// },
		}); err != nil {
		panic(err)
	}

	rtpVideo, err := connection.AddTrack(manager.videoTrack)
	if err != nil {
		return nil, err
	}
	
	rtpAudio, err := connection.AddTrack(manager.audioTrack)
	if err != nil {
		return nil, err
	}
       
       // <----------- snip a lot of code -------------------->

	// Read incoming RTCP packets
	// Before these packets are returned they are processed by interceptors. For things
	// like NACK this needs to be called.
	go func() {
		rtcpBuf := make([]byte, 1500)
		for {
			if _, _, rtcpErr := rtpVideo.Read(rtcpBuf); rtcpErr != nil {
				return
			}
		}
	}()

	go func() {
		rtcpBuf := make([]byte, 1500)
		for {
			if _, _, rtcpErr := rtpAudio.Read(rtcpBuf); rtcpErr != nil {
				return
			}
		}
	}()