sending audio data back on rtp sendrecv

[n0rt0nthec4t]

I'm fairly new to WebRTC and this project. I'm trying to work out how to send audio packet data BACK over the rtp channel that is created.

My PeerConnection is created using teh following codec config:

      codecs: {
            audio: [
              new wrtc.RTCRtpCodecParameters({
                mimeType: 'audio/opus',
                clockRate: 48000,
                channels: 2,
                payloadType: RTP_AUDIO_PAYLOAD_TYPE,
              }),
            ],

and used the following to add a transceiver

let audio = pc.addTransceiver('audio', {
          direction: 'sendrecv',
        });

handling incoming audio packets via

         audio.onTrack.subscribe((track) => {

            track.onReceiveRtp.subscribe((rtp) => {
              incoming(rtp);
            });
          });