I want to add Closed Captions for a SIP call

Question

I have added a code which is showing captions of my mic. I want to capture the voice of the person in call and show the captions in my page in real time.

`function sipInitialize(){
JsSIP.debug.enable('JsSIP:*');

var socket = new JsSIP.WebSocketInterface(websocket_proxy_url);
var configuration = {
sockets : [ socket ],
uri : sip_identity,
password : "5789",
register : true,
};
ua = new JsSIP.UA(configuration);
ua.start();

navigator.mediaDevices.getUserMedia({ audio: true })
ua.on('connected', function(e) {
  console.log('connected...' + e)
  createSipSession()
});

ua.on('trackAdded', function(track) {
  if (track.kind === 'audio') {
    track.on('started', function() {
      var recognition = new window.webkitSpeechRecognition();
      recognition.continuous = true;
      recognition.interimResults = true;
      
      // Update the text of the #transcript paragraph element
      $('#transcript').text("Listening...");
      
      recognition.onresult = function(event) {
        var transcript = event.results[event.results.length - 1][0].transcript;
        console.log('Transcript:', transcript);
        
        // Update the text of the #transcript paragraph element
        $('#transcript').text(transcript);
        
        socket.emit('transcription', transcript);
      };
      
      recognition.onend = function() {
        console.log('Speech recognition ended');
        
        // Update the text of the #transcript paragraph element
        $('#transcript').text("Speech recognition ended.");
      };
      
      recognition.onerror = function(event) {
        console.error('Speech recognition error:', event.error);
        
        // Update the text of the #transcript paragraph element
        $('#transcript').text("Speech recognition error.");
      };
      
      var mediaStream = new MediaStream([track.mediaStreamTrack]);
      recognition.start();
      recognition.stream = mediaStream;
    })
  }
});`

I am expecting that I have to capture the voice of a person who is in call (may be VoIP or cellular)and get their Transcription in my page using JavaScript inbuilt speech recognition library