unserver-unify/src/assets/audio/recordLive.js

var audio_context,
    recorder,
    volume,
    volumeLevel = 0,
    currentEditedSoundIndex;
var _stream;

function startUserMedia(stream,callback) {
  //console.log(stream);
  _stream=stream;
  var input = audio_context.createMediaStreamSource(stream);
  console.log('Media stream created.');

  volume = audio_context.createGain();
  volume.gain.value = volumeLevel;
  input.connect(volume);
  volume.connect(audio_context.destination);
  console.log('Input connected to audio context destination.');
  
  recorder = new Recorder(input);
  console.log('Recorder initialised.');
  callback();
}



function startRecording(button) {
  var audioRef = document.getElementById('audiosStatus');
  audioRef.innerHTML="Waiting for Permission ....";
  init(function(){
    recorder && recorder.record();
    
    audioRef.innerHTML="Recording ....";
    button.disabled = true;
    button.nextElementSibling.disabled = false;
    console.log('Recording...');
  });
}

function stopRecording(button) {
  recorder && recorder.stop();
  _stream.getTracks()[0].stop();
  button.disabled = true;
  button.previousElementSibling.disabled = false;
  console.log('Stopped recording.');
  var audioRef = document.getElementById('audiosStatus');
  audioRef.innerHTML="Converting ....";
  
  // create WAV download link using audio data blob
  createDownloadLink();
  
  recorder.clear();
}

function createDownloadLink() {
  currentEditedSoundIndex = -1;
  recorder && recorder.exportWAV(handleWAV.bind(this));
}

function handleWAV(blob) {
 // var tableRef = document.getElementById('recordingslist');
 /*var audioRef = document.getElementById('audioslist');
  while (audioRef.hasChildNodes()) {
    audioRef.removeChild(audioRef.lastChild);
  }
  var url = URL.createObjectURL(blob);
  var audioElement = document.createElement('audio');
  audioElement.controls = true;
  audioElement.src = url;
  var li = document.createElement('div');
  li.appendChild(audioElement);
  audioRef.appendChild(li);*/
}

function init(callback) {
  try {
    // webkit shim
    window.AudioContext = window.AudioContext || window.webkitAudioContext || window.mozAudioContext;
    navigator.getUserMedia = navigator.getUserMedia || navigator.webkitGetUserMedia || navigator.mozGetUserMedia;
    window.URL = window.URL || window.webkitURL || window.mozURL;
    
    audio_context = new AudioContext();
    console.log('Audio context set up.');
    console.log('navigator.getUserMedia ' + (navigator.getUserMedia ? 'available.' : 'not present!'));
  } catch (e) {
    console.warn('No web audio support in this browser!');
  }
  
  navigator.getUserMedia({audio: true}, function(stream){
    startUserMedia(stream,callback);
  }, function(e) {
    console.warn('No live audio input: ' + e);
  });
};