main.js

/*
 *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree.
 */

/* global AudioContext, SoundMeter */

'use strict';

const startButton = document.getElementById('recordButton');
const stopButton = document.getElementById('stopButton');
startButton.onclick = start;
stopButton.onclick = stop;

const instantMeter = document.querySelector('#instant meter');
const slowMeter = document.querySelector('#slow meter');
const clipMeter = document.querySelector('#clip meter');

const instantValueDisplay = document.querySelector('#instant .value');
const slowValueDisplay = document.querySelector('#slow .value');
const clipValueDisplay = document.querySelector('#clip .value');

// Put variables in global scope to make them available to the browser console.
const constraints = window.constraints = {
  audio: true,
  video: false
};

let meterRefresh = null;

function handleSuccess(stream) {
  // Put variables in global scope to make them available to the
  // browser console.
  window.stream = stream;
  const soundMeter = window.soundMeter = new SoundMeter(window.audioContext);
  soundMeter.connectToSource(stream, function(e) {
    if (e) {
      alert(e);
      return;
    }
    meterRefresh = setInterval(() => {
      instantMeter.value = instantValueDisplay.innerText =
        soundMeter.instant.toFixed(2);
      slowMeter.value = slowValueDisplay.innerText =
        soundMeter.slow.toFixed(2);
      clipMeter.value = clipValueDisplay.innerText =
        soundMeter.clip;
    }, 200);
  });
}

function handleError(error) {
  console.log('navigator.MediaDevices.getUserMedia error: ', error.message, error.name);
}


function start() {
  console.log('Requesting local stream');
  startButton.disabled = true;
  stopButton.disabled = false;

  try {
    window.AudioContext = window.AudioContext || window.webkitAudioContext;
    window.audioContext = new AudioContext();
  } catch (e) {
    alert('Web Audio API not supported.');
  }

  navigator.mediaDevices
      .getUserMedia(constraints)
      .then(handleSuccess)
      .catch(handleError);
}

function stop() {
  console.log('Stopping local stream');
  startButton.disabled = false;
  stopButton.disabled = true;

  window.stream.getTracks().forEach(track => track.stop());
  window.soundMeter.stop();
  window.audioContext.close();
  clearInterval(meterRefresh);
  instantMeter.value = instantValueDisplay.innerText = '';
  slowMeter.value = slowValueDisplay.innerText = '';
  clipMeter.value = clipValueDisplay.innerText = '';
}