GeSHi Source Viewer: howler.orig.js

```
/*!
```
```
 *  howler.js v2.2.3
```
```
 *  howlerjs.com
```
```
 *
```

 *  (c) 2013-2020, James Simpson of GoldFire Studios

```
 *  goldfirestudios.com
```
```
 *
```
```
 *  MIT License
```
```
 */
```
```
 
```
```
(function() {
```
```
 
```
```
  'use strict';
```
```
 
```
```
  /** Global Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```

   * Create the global controller. All contained methods and properties apply

   * to all sounds that are currently playing or will be in the future.

```
   */
```
```
  var HowlerGlobal = function() {
```
```
    this.init();
```
```
  };
```
```
  HowlerGlobal.prototype = {
```
```
    /**
```

     * Initialize the global Howler object.

```
     * @return {Howler}
```
```
     */
```
```
    init: function() {
```
```
      var self = this || Howler;
```
```
 
```
```
      // Create a global ID counter.
```
```
      self._counter = 1000;
```
```
 
```

      // Pool of unlocked HTML5 Audio objects.

```
      self._html5AudioPool = [];
```
```
      self.html5PoolSize = 10;
```
```
 
```
```
      // Internal properties.
```
```
      self._codecs = {};
```
```
      self._howls = [];
```
```
      self._muted = false;
```
```
      self._volume = 1;
```

      self._canPlayEvent = 'canplaythrough';

      self._navigator = (typeof window !== 'undefined' && window.navigator) ? window.navigator : null;

```
 
```
```
      // Public properties.
```
```
      self.masterGain = null;
```
```
      self.noAudio = false;
```
```
      self.usingWebAudio = true;
```
```
      self.autoSuspend = true;
```
```
      self.ctx = null;
```
```
 
```

      // Set to false to disable the auto audio unlocker.

```
      self.autoUnlock = true;
```
```
 
```

      // Setup the various state values for global tracking.

```
      self._setup();
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Get/set the global volume for all sounds.

     * @param  {Float} vol Volume from 0.0 to 1.0.

     * @return {Howler/Float}     Returns self or current volume.

```
     */
```
```
    volume: function(vol) {
```
```
      var self = this || Howler;
```
```
      vol = parseFloat(vol);
```
```
 
```

      // If we don't have an AudioContext created yet, run the setup.

```
      if (!self.ctx) {
```
```
        setupAudioContext();
```
```
      }
```
```
 
```

      if (typeof vol !== 'undefined' && vol >= 0 && vol <= 1) {

```
        self._volume = vol;
```
```
 
```

        // Don't update any of the nodes if we are muted.

```
        if (self._muted) {
```
```
          return self;
```
```
        }
```
```
 
```

        // When using Web Audio, we just need to adjust the master gain.

```
        if (self.usingWebAudio) {
```

          self.masterGain.gain.setValueAtTime(vol, Howler.ctx.currentTime);

```
        }
```
```
 
```

        // Loop through and change volume for all HTML5 audio nodes.

        for (var i=0; i<self._howls.length; i++) {

          if (!self._howls[i]._webAudio) {

            // Get all of the sounds in this Howl group.

            var ids = self._howls[i]._getSoundIds();

```
 
```

            // Loop through all sounds and change the volumes.

            for (var j=0; j<ids.length; j++) {

              var sound = self._howls[i]._soundById(ids[j]);

```
 
```

              if (sound && sound._node) {

                sound._node.volume = sound._volume * vol;

```
              }
```
```
            }
```
```
          }
```
```
        }
```
```
 
```
```
        return self;
```
```
      }
```
```
 
```
```
      return self._volume;
```
```
    },
```
```
 
```
```
    /**
```

     * Handle muting and unmuting globally.

     * @param  {Boolean} muted Is muted or not.

```
     */
```
```
    mute: function(muted) {
```
```
      var self = this || Howler;
```
```
 
```

      // If we don't have an AudioContext created yet, run the setup.

```
      if (!self.ctx) {
```
```
        setupAudioContext();
```
```
      }
```
```
 
```
```
      self._muted = muted;
```
```
 
```

      // With Web Audio, we just need to mute the master gain.

```
      if (self.usingWebAudio) {
```

        self.masterGain.gain.setValueAtTime(muted ? 0 : self._volume, Howler.ctx.currentTime);

```
      }
```
```
 
```

      // Loop through and mute all HTML5 Audio nodes.

      for (var i=0; i<self._howls.length; i++) {

        if (!self._howls[i]._webAudio) {

          // Get all of the sounds in this Howl group.

          var ids = self._howls[i]._getSoundIds();

```
 
```

          // Loop through all sounds and mark the audio node as muted.

          for (var j=0; j<ids.length; j++) {

            var sound = self._howls[i]._soundById(ids[j]);

```
 
```
```
            if (sound && sound._node) {
```

              sound._node.muted = (muted) ? true : sound._muted;

```
            }
```
```
          }
```
```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Handle stopping all sounds globally.

```
     */
```
```
    stop: function() {
```
```
      var self = this || Howler;
```
```
 
```

      // Loop through all Howls and stop them.

      for (var i=0; i<self._howls.length; i++) {

```
        self._howls[i].stop();
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Unload and destroy all currently loaded Howl objects.

```
     * @return {Howler}
```
```
     */
```
```
    unload: function() {
```
```
      var self = this || Howler;
```
```
 
```

      for (var i=self._howls.length-1; i>=0; i--) {

```
        self._howls[i].unload();
```
```
      }
```
```
 
```

      // Create a new AudioContext to make sure it is fully reset.

      if (self.usingWebAudio && self.ctx && typeof self.ctx.close !== 'undefined') {

```
        self.ctx.close();
```
```
        self.ctx = null;
```
```
        setupAudioContext();
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Check for codec support of specific extension.

     * @param  {String} ext Audio file extention.

```
     * @return {Boolean}
```
```
     */
```
```
    codecs: function(ext) {
```

      return (this || Howler)._codecs[ext.replace(/^x-/, '')];

```
    },
```
```
 
```
```
    /**
```

     * Setup various state values for global tracking.

```
     * @return {Howler}
```
```
     */
```
```
    _setup: function() {
```
```
      var self = this || Howler;
```
```
 
```

      // Keeps track of the suspend/resume state of the AudioContext.

      self.state = self.ctx ? self.ctx.state || 'suspended' : 'suspended';

```
 
```

      // Automatically begin the 30-second suspend process

```
      self._autoSuspend();
```
```
 
```
```
      // Check if audio is available.
```
```
      if (!self.usingWebAudio) {
```

        // No audio is available on this system if noAudio is set to true.

        if (typeof Audio !== 'undefined') {

```
          try {
```
```
            var test = new Audio();
```
```
 
```

            // Check if the canplaythrough event is available.

            if (typeof test.oncanplaythrough === 'undefined') {

              self._canPlayEvent = 'canplay';

```
            }
```
```
          } catch(e) {
```
```
            self.noAudio = true;
```
```
          }
```
```
        } else {
```
```
          self.noAudio = true;
```
```
        }
```
```
      }
```
```
 
```

      // Test to make sure audio isn't disabled in Internet Explorer.

```
      try {
```
```
        var test = new Audio();
```
```
        if (test.muted) {
```
```
          self.noAudio = true;
```
```
        }
```
```
      } catch (e) {}
```
```
 
```
```
      // Check for supported codecs.
```
```
      if (!self.noAudio) {
```
```
        self._setupCodecs();
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Check for browser support for various codecs and cache the results.

```
     * @return {Howler}
```
```
     */
```
```
    _setupCodecs: function() {
```
```
      var self = this || Howler;
```
```
      var audioTest = null;
```
```
 
```

      // Must wrap in a try/catch because IE11 in server mode throws an error.

```
      try {
```

        audioTest = (typeof Audio !== 'undefined') ? new Audio() : null;

```
      } catch (err) {
```
```
        return self;
```
```
      }
```
```
 
```

      if (!audioTest || typeof audioTest.canPlayType !== 'function') {

```
        return self;
```
```
      }
```
```
 
```

      var mpegTest = audioTest.canPlayType('audio/mpeg;').replace(/^no$/, '');

```
 
```

      // Opera version <33 has mixed MP3 support, so we need to check for and block it.

      var ua = self._navigator ? self._navigator.userAgent : '';

      var checkOpera = ua.match(/OPR\/([0-6].)/g);

      var isOldOpera = (checkOpera && parseInt(checkOpera[0].split('/')[1], 10) < 33);

      var checkSafari = ua.indexOf('Safari') !== -1 && ua.indexOf('Chrome') === -1;

      var safariVersion = ua.match(/Version\/(.*?) /);

      var isOldSafari = (checkSafari && safariVersion && parseInt(safariVersion[1], 10) < 15);

```
 
```
```
      self._codecs = {
```

        mp3: !!(!isOldOpera && (mpegTest || audioTest.canPlayType('audio/mp3;').replace(/^no$/, ''))),

```
        mpeg: !!mpegTest,
```

        opus: !!audioTest.canPlayType('audio/ogg; codecs="opus"').replace(/^no$/, ''),

        ogg: !!audioTest.canPlayType('audio/ogg; codecs="vorbis"').replace(/^no$/, ''),

        oga: !!audioTest.canPlayType('audio/ogg; codecs="vorbis"').replace(/^no$/, ''),

        wav: !!(audioTest.canPlayType('audio/wav; codecs="1"') || audioTest.canPlayType('audio/wav')).replace(/^no$/, ''),

        aac: !!audioTest.canPlayType('audio/aac;').replace(/^no$/, ''),

        caf: !!audioTest.canPlayType('audio/x-caf;').replace(/^no$/, ''),

        m4a: !!(audioTest.canPlayType('audio/x-m4a;') || audioTest.canPlayType('audio/m4a;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),

        m4b: !!(audioTest.canPlayType('audio/x-m4b;') || audioTest.canPlayType('audio/m4b;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),

        mp4: !!(audioTest.canPlayType('audio/x-mp4;') || audioTest.canPlayType('audio/mp4;') || audioTest.canPlayType('audio/aac;')).replace(/^no$/, ''),

        weba: !!(!isOldSafari && audioTest.canPlayType('audio/webm; codecs="vorbis"').replace(/^no$/, '')),

        webm: !!(!isOldSafari && audioTest.canPlayType('audio/webm; codecs="vorbis"').replace(/^no$/, '')),

        dolby: !!audioTest.canPlayType('audio/mp4; codecs="ec-3"').replace(/^no$/, ''),

        flac: !!(audioTest.canPlayType('audio/x-flac;') || audioTest.canPlayType('audio/flac;')).replace(/^no$/, '')

```
      };
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Some browsers/devices will only allow audio to be played after a user interaction.

     * Attempt to automatically unlock audio on the first user interaction.

     * Concept from: http://paulbakaus.com/tutorials/html5/web-audio-on-ios/

```
     * @return {Howler}
```
```
     */
```
```
    _unlockAudio: function() {
```
```
      var self = this || Howler;
```
```
 
```

      // Only run this if Web Audio is supported and it hasn't already been unlocked.

      if (self._audioUnlocked || !self.ctx) {

```
        return;
```
```
      }
```
```
 
```
```
      self._audioUnlocked = false;
```
```
      self.autoUnlock = false;
```
```
 
```

      // Some mobile devices/platforms have distortion issues when opening/closing tabs and/or web views.

      // Bugs in the browser (especially Mobile Safari) can cause the sampleRate to change from 44100 to 48000.

      // By calling Howler.unload(), we create a new AudioContext with the correct sampleRate.

      if (!self._mobileUnloaded && self.ctx.sampleRate !== 44100) {

```
        self._mobileUnloaded = true;
```
```
        self.unload();
```
```
      }
```
```
 
```

      // Scratch buffer for enabling iOS to dispose of web audio buffers correctly, as per:

      // http://stackoverflow.com/questions/24119684

      self._scratchBuffer = self.ctx.createBuffer(1, 1, 22050);

```
 
```

      // Call this method on touch start to create and play a buffer,

      // then check if the audio actually played to determine if

      // audio has now been unlocked on iOS, Android, etc.

```
      var unlock = function(e) {
```

        // Create a pool of unlocked HTML5 Audio objects that can

        // be used for playing sounds without user interaction. HTML5

        // Audio objects must be individually unlocked, as opposed

        // to the WebAudio API which only needs a single activation.

        // This must occur before WebAudio setup or the source.onended

```
        // event will not fire.
```

        while (self._html5AudioPool.length < self.html5PoolSize) {

```
          try {
```

            var audioNode = new Audio();

```
 
```

            // Mark this Audio object as unlocked to ensure it can get returned

            // to the unlocked pool when released.

```
            audioNode._unlocked = true;
```
```
 
```

            // Add the audio node to the pool.

            self._releaseHtml5Audio(audioNode);

```
          } catch (e) {
```
```
            self.noAudio = true;
```
```
            break;
```
```
          }
```
```
        }
```
```
 
```

        // Loop through any assigned audio nodes and unlock them.

        for (var i=0; i<self._howls.length; i++) {

          if (!self._howls[i]._webAudio) {

            // Get all of the sounds in this Howl group.

            var ids = self._howls[i]._getSoundIds();

```
 
```

            // Loop through all sounds and unlock the audio nodes.

            for (var j=0; j<ids.length; j++) {

              var sound = self._howls[i]._soundById(ids[j]);

```
 
```

              if (sound && sound._node && !sound._node._unlocked) {

                sound._node._unlocked = true;

```
                sound._node.load();
```
```
              }
```
```
            }
```
```
          }
```
```
        }
```
```
 
```

        // Fix Android can not play in suspend state.

```
        self._autoResume();
```
```
 
```
```
        // Create an empty buffer.
```

        var source = self.ctx.createBufferSource();

        source.buffer = self._scratchBuffer;

        source.connect(self.ctx.destination);

```
 
```
```
        // Play the empty buffer.
```

        if (typeof source.start === 'undefined') {

```
          source.noteOn(0);
```
```
        } else {
```
```
          source.start(0);
```
```
        }
```
```
 
```

        // Calling resume() on a stack initiated by user gesture is what actually unlocks the audio on Android Chrome >= 55.

        if (typeof self.ctx.resume === 'function') {

```
          self.ctx.resume();
```
```
        }
```
```
 
```

        // Setup a timeout to check that we are unlocked on the next event loop.

```
        source.onended = function() {
```
```
          source.disconnect(0);
```
```
 
```

          // Update the unlocked state and prevent this check from happening again.

```
          self._audioUnlocked = true;
```
```
 
```

          // Remove the touch start listener.

          document.removeEventListener('touchstart', unlock, true);

          document.removeEventListener('touchend', unlock, true);

          document.removeEventListener('click', unlock, true);

          document.removeEventListener('keydown', unlock, true);

```
 
```

          // Let all sounds know that audio has been unlocked.

          for (var i=0; i<self._howls.length; i++) {

            self._howls[i]._emit('unlock');

```
          }
```
```
        };
```
```
      };
```
```
 
```

      // Setup a touch start listener to attempt an unlock in.

      document.addEventListener('touchstart', unlock, true);

      document.addEventListener('touchend', unlock, true);

      document.addEventListener('click', unlock, true);

      document.addEventListener('keydown', unlock, true);

```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Get an unlocked HTML5 Audio object from the pool. If none are left,

     * return a new Audio object and throw a warning.

     * @return {Audio} HTML5 Audio object.

```
     */
```
```
    _obtainHtml5Audio: function() {
```
```
      var self = this || Howler;
```
```
 
```

      // Return the next object from the pool if one exists.

      if (self._html5AudioPool.length) {

        return self._html5AudioPool.pop();

```
      }
```
```
 
```

      //.Check if the audio is locked and throw a warning.

      var testPlay = new Audio().play();

      if (testPlay && typeof Promise !== 'undefined' && (testPlay instanceof Promise || typeof testPlay.then === 'function')) {

```
        testPlay.catch(function() {
```

          console.warn('HTML5 Audio pool exhausted, returning potentially locked audio object.');

```
        });
```
```
      }
```
```
 
```
```
      return new Audio();
```
```
    },
```
```
 
```
```
    /**
```

     * Return an activated HTML5 Audio object to the pool.

```
     * @return {Howler}
```
```
     */
```

    _releaseHtml5Audio: function(audio) {

```
      var self = this || Howler;
```
```
 
```

      // Don't add audio to the pool if we don't know if it has been unlocked.

```
      if (audio._unlocked) {
```

        self._html5AudioPool.push(audio);

```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Automatically suspend the Web Audio AudioContext after no sound has played for 30 seconds.

     * This saves processing/energy and fixes various browser-specific bugs with audio getting stuck.

```
     * @return {Howler}
```
```
     */
```
```
    _autoSuspend: function() {
```
```
      var self = this;
```
```
 
```

      if (!self.autoSuspend || !self.ctx || typeof self.ctx.suspend === 'undefined' || !Howler.usingWebAudio) {

```
        return;
```
```
      }
```
```
 
```

      // Check if any sounds are playing.

      for (var i=0; i<self._howls.length; i++) {

```
        if (self._howls[i]._webAudio) {
```

          for (var j=0; j<self._howls[i]._sounds.length; j++) {

            if (!self._howls[i]._sounds[j]._paused) {

```
              return self;
```
```
            }
```
```
          }
```
```
        }
```
```
      }
```
```
 
```
```
      if (self._suspendTimer) {
```

        clearTimeout(self._suspendTimer);

```
      }
```
```
 
```

      // If no sound has played after 30 seconds, suspend the context.

      self._suspendTimer = setTimeout(function() {

```
        if (!self.autoSuspend) {
```
```
          return;
```
```
        }
```
```
 
```
```
        self._suspendTimer = null;
```
```
        self.state = 'suspending';
```
```
 
```

        // Handle updating the state of the audio context after suspending.

        var handleSuspension = function() {

```
          self.state = 'suspended';
```
```
 
```

          if (self._resumeAfterSuspend) {

            delete self._resumeAfterSuspend;

```
            self._autoResume();
```
```
          }
```
```
        };
```
```
 
```

        // Either the state gets suspended or it is interrupted.

        // Either way, we need to update the state to suspended.

        self.ctx.suspend().then(handleSuspension, handleSuspension);

```
      }, 30000);
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Automatically resume the Web Audio AudioContext when a new sound is played.

```
     * @return {Howler}
```
```
     */
```
```
    _autoResume: function() {
```
```
      var self = this;
```
```
 
```

      if (!self.ctx || typeof self.ctx.resume === 'undefined' || !Howler.usingWebAudio) {

```
        return;
```
```
      }
```
```
 
```

      if (self.state === 'running' && self.ctx.state !== 'interrupted' && self._suspendTimer) {

        clearTimeout(self._suspendTimer);

```
        self._suspendTimer = null;
```

      } else if (self.state === 'suspended' || self.state === 'running' && self.ctx.state === 'interrupted') {

        self.ctx.resume().then(function() {

```
          self.state = 'running';
```
```
 
```

          // Emit to all Howls that the audio has resumed.

          for (var i=0; i<self._howls.length; i++) {

            self._howls[i]._emit('resume');

```
          }
```
```
        });
```
```
 
```
```
        if (self._suspendTimer) {
```

          clearTimeout(self._suspendTimer);

```
          self._suspendTimer = null;
```
```
        }
```

      } else if (self.state === 'suspending') {

        self._resumeAfterSuspend = true;

```
      }
```
```
 
```
```
      return self;
```
```
    }
```
```
  };
```
```
 
```
```
  // Setup the global audio controller.
```
```
  var Howler = new HowlerGlobal();
```
```
 
```
```
  /** Group Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```
```
   * Create an audio group controller.
```

   * @param {Object} o Passed in properties for this group.

```
   */
```
```
  var Howl = function(o) {
```
```
    var self = this;
```
```
 
```

    // Throw an error if no source is provided.

```
    if (!o.src || o.src.length === 0) {
```

      console.error('An array of source files must be passed with any new Howl.');

```
      return;
```
```
    }
```
```
 
```
```
    self.init(o);
```
```
  };
```
```
  Howl.prototype = {
```
```
    /**
```

     * Initialize a new Howl group object.

     * @param  {Object} o Passed in properties for this group.

```
     * @return {Howl}
```
```
     */
```
```
    init: function(o) {
```
```
      var self = this;
```
```
 
```

      // If we don't have an AudioContext created yet, run the setup.

```
      if (!Howler.ctx) {
```
```
        setupAudioContext();
```
```
      }
```
```
 
```

      // Setup user-defined default properties.

      self._autoplay = o.autoplay || false;

      self._format = (typeof o.format !== 'string') ? o.format : [o.format];

```
      self._html5 = o.html5 || false;
```
```
      self._muted = o.mute || false;
```
```
      self._loop = o.loop || false;
```
```
      self._pool = o.pool || 5;
```

      self._preload = (typeof o.preload === 'boolean' || o.preload === 'metadata') ? o.preload : true;

```
      self._rate = o.rate || 1;
```
```
      self._sprite = o.sprite || {};
```

      self._src = (typeof o.src !== 'string') ? o.src : [o.src];

      self._volume = o.volume !== undefined ? o.volume : 1;

```
      self._xhr = {
```

        method: o.xhr && o.xhr.method ? o.xhr.method : 'GET',

        headers: o.xhr && o.xhr.headers ? o.xhr.headers : null,

        withCredentials: o.xhr && o.xhr.withCredentials ? o.xhr.withCredentials : false,

```
      };
```
```
 
```

      // Setup all other default properties.

```
      self._duration = 0;
```
```
      self._state = 'unloaded';
```
```
      self._sounds = [];
```
```
      self._endTimers = {};
```
```
      self._queue = [];
```
```
      self._playLock = false;
```
```
 
```
```
      // Setup event listeners.
```

      self._onend = o.onend ? [{fn: o.onend}] : [];

      self._onfade = o.onfade ? [{fn: o.onfade}] : [];

      self._onload = o.onload ? [{fn: o.onload}] : [];

      self._onloaderror = o.onloaderror ? [{fn: o.onloaderror}] : [];

      self._onplayerror = o.onplayerror ? [{fn: o.onplayerror}] : [];

      self._onpause = o.onpause ? [{fn: o.onpause}] : [];

      self._onplay = o.onplay ? [{fn: o.onplay}] : [];

      self._onstop = o.onstop ? [{fn: o.onstop}] : [];

      self._onmute = o.onmute ? [{fn: o.onmute}] : [];

      self._onvolume = o.onvolume ? [{fn: o.onvolume}] : [];

      self._onrate = o.onrate ? [{fn: o.onrate}] : [];

      self._onseek = o.onseek ? [{fn: o.onseek}] : [];

      self._onunlock = o.onunlock ? [{fn: o.onunlock}] : [];

```
      self._onresume = [];
```
```
 
```
```
      // Web Audio or HTML5 Audio?
```

      self._webAudio = Howler.usingWebAudio && !self._html5;

```
 
```

      // Automatically try to enable audio.

      if (typeof Howler.ctx !== 'undefined' && Howler.ctx && Howler.autoUnlock) {

```
        Howler._unlockAudio();
```
```
      }
```
```
 
```

      // Keep track of this Howl group in the global controller.

```
      Howler._howls.push(self);
```
```
 
```

      // If they selected autoplay, add a play event to the load queue.

```
      if (self._autoplay) {
```
```
        self._queue.push({
```
```
          event: 'play',
```
```
          action: function() {
```
```
            self.play();
```
```
          }
```
```
        });
```
```
      }
```
```
 
```

      // Load the source file unless otherwise specified.

      if (self._preload && self._preload !== 'none') {

```
        self.load();
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```
```
     * Load the audio file.
```
```
     * @return {Howler}
```
```
     */
```
```
    load: function() {
```
```
      var self = this;
```
```
      var url = null;
```
```
 
```

      // If no audio is available, quit immediately.

```
      if (Howler.noAudio) {
```

        self._emit('loaderror', null, 'No audio support.');

```
        return;
```
```
      }
```
```
 
```

      // Make sure our source is in an array.

      if (typeof self._src === 'string') {

```
        self._src = [self._src];
```
```
      }
```
```
 
```

      // Loop through the sources and pick the first one that is compatible.

      for (var i=0; i<self._src.length; i++) {

```
        var ext, str;
```
```
 
```

        if (self._format && self._format[i]) {

          // If an extension was specified, use that instead.

```
          ext = self._format[i];
```
```
        } else {
```

          // Make sure the source is a string.

```
          str = self._src[i];
```

          if (typeof str !== 'string') {

            self._emit('loaderror', null, 'Non-string found in selected audio sources - ignoring.');

```
            continue;
```
```
          }
```
```
 
```

          // Extract the file extension from the URL or base64 data URI.

          ext = /^data:audio\/([^;,]+);/i.exec(str);

```
          if (!ext) {
```

            ext = /\.([^.]+)$/.exec(str.split('?', 1)[0]);

```
          }
```
```
 
```
```
          if (ext) {
```
```
            ext = ext[1].toLowerCase();
```
```
          }
```
```
        }
```
```
 
```

        // Log a warning if no extension was found.

```
        if (!ext) {
```

          console.warn('No file extension was found. Consider using the "format" property or specify an extension.');

```
        }
```
```
 
```

        // Check if this extension is available.

        if (ext && Howler.codecs(ext)) {

```
          url = self._src[i];
```
```
          break;
```
```
        }
```
```
      }
```
```
 
```
```
      if (!url) {
```

        self._emit('loaderror', null, 'No codec support for selected audio sources.');

```
        return;
```
```
      }
```
```
 
```
```
      self._src = url;
```
```
      self._state = 'loading';
```
```
 
```

      // If the hosting page is HTTPS and the source isn't,

      // drop down to HTML5 Audio to avoid Mixed Content errors.

      if (window.location.protocol === 'https:' && url.slice(0, 5) === 'http:') {

```
        self._html5 = true;
```
```
        self._webAudio = false;
```
```
      }
```
```
 
```

      // Create a new sound object and add it to the pool.

```
      new Sound(self);
```
```
 
```

      // Load and decode the audio data for playback.

```
      if (self._webAudio) {
```
```
        loadBuffer(self);
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Play a sound or resume previous playback.

     * @param  {String/Number} sprite   Sprite name for sprite playback or sound id to continue previous.

     * @param  {Boolean} internal Internal Use: true prevents event firing.

     * @return {Number}          Sound ID.

```
     */
```
```
    play: function(sprite, internal) {
```
```
      var self = this;
```
```
      var id = null;
```
```
 
```

      // Determine if a sprite, sound id or nothing was passed

```
      if (typeof sprite === 'number') {
```
```
        id = sprite;
```
```
        sprite = null;
```

      } else if (typeof sprite === 'string' && self._state === 'loaded' && !self._sprite[sprite]) {

        // If the passed sprite doesn't exist, do nothing.

```
        return null;
```

      } else if (typeof sprite === 'undefined') {

        // Use the default sound sprite (plays the full audio length).

```
        sprite = '__default';
```
```
 
```

        // Check if there is a single paused sound that isn't ended.

        // If there is, play that sound. If not, continue as usual.

```
        if (!self._playLock) {
```
```
          var num = 0;
```

          for (var i=0; i<self._sounds.length; i++) {

            if (self._sounds[i]._paused && !self._sounds[i]._ended) {

```
              num++;
```
```
              id = self._sounds[i]._id;
```
```
            }
```
```
          }
```
```
 
```
```
          if (num === 1) {
```
```
            sprite = null;
```
```
          } else {
```
```
            id = null;
```
```
          }
```
```
        }
```
```
      }
```
```
 
```

      // Get the selected node, or get one from the pool.

      var sound = id ? self._soundById(id) : self._inactiveSound();

```
 
```

      // If the sound doesn't exist, do nothing.

```
      if (!sound) {
```
```
        return null;
```
```
      }
```
```
 
```
```
      // Select the sprite definition.
```
```
      if (id && !sprite) {
```

        sprite = sound._sprite || '__default';

```
      }
```
```
 
```

      // If the sound hasn't loaded, we must wait to get the audio's duration.

      // We also need to wait to make sure we don't run into race conditions with

```
      // the order of function calls.
```
```
      if (self._state !== 'loaded') {
```

        // Set the sprite value on this sound.

```
        sound._sprite = sprite;
```
```
 
```

        // Mark this sound as not ended in case another sound is played before this one loads.

```
        sound._ended = false;
```
```
 
```

        // Add the sound to the queue to be played on load.

```
        var soundId = sound._id;
```
```
        self._queue.push({
```
```
          event: 'play',
```
```
          action: function() {
```
```
            self.play(soundId);
```
```
          }
```
```
        });
```
```
 
```
```
        return soundId;
```
```
      }
```
```
 
```

      // Don't play the sound if an id was passed and it is already playing.

```
      if (id && !sound._paused) {
```

        // Trigger the play event, in order to keep iterating through queue.

```
        if (!internal) {
```
```
          self._loadQueue('play');
```
```
        }
```
```
 
```
```
        return sound._id;
```
```
      }
```
```
 
```

      // Make sure the AudioContext isn't suspended, and resume it if it is.

```
      if (self._webAudio) {
```
```
        Howler._autoResume();
```
```
      }
```
```
 
```

      // Determine how long to play for and where to start playing.

      var seek = Math.max(0, sound._seek > 0 ? sound._seek : self._sprite[sprite][0] / 1000);

      var duration = Math.max(0, ((self._sprite[sprite][0] + self._sprite[sprite][1]) / 1000) - seek);

      var timeout = (duration * 1000) / Math.abs(sound._rate);

      var start = self._sprite[sprite][0] / 1000;

      var stop = (self._sprite[sprite][0] + self._sprite[sprite][1]) / 1000;

```
      sound._sprite = sprite;
```
```
 
```

      // Mark the sound as ended instantly so that this async playback

      // doesn't get grabbed by another call to play while this one waits to start.

```
      sound._ended = false;
```
```
 
```

      // Update the parameters of the sound.

```
      var setParams = function() {
```
```
        sound._paused = false;
```
```
        sound._seek = seek;
```
```
        sound._start = start;
```
```
        sound._stop = stop;
```

        sound._loop = !!(sound._loop || self._sprite[sprite][2]);

```
      };
```
```
 
```

      // End the sound instantly if seek is at the end.

```
      if (seek >= stop) {
```
```
        self._ended(sound);
```
```
        return;
```
```
      }
```
```
 
```
```
      // Begin the actual playback.
```
```
      var node = sound._node;
```
```
      if (self._webAudio) {
```

        // Fire this when the sound is ready to play to begin Web Audio playback.

```
        var playWebAudio = function() {
```
```
          self._playLock = false;
```
```
          setParams();
```
```
          self._refreshBuffer(sound);
```
```
 
```
```
          // Setup the playback params.
```

          var vol = (sound._muted || self._muted) ? 0 : sound._volume;

          node.gain.setValueAtTime(vol, Howler.ctx.currentTime);

          sound._playStart = Howler.ctx.currentTime;

```
 
```

          // Play the sound using the supported method.

          if (typeof node.bufferSource.start === 'undefined') {

            sound._loop ? node.bufferSource.noteGrainOn(0, seek, 86400) : node.bufferSource.noteGrainOn(0, seek, duration);

```
          } else {
```

            sound._loop ? node.bufferSource.start(0, seek, 86400) : node.bufferSource.start(0, seek, duration);

```
          }
```
```
 
```

          // Start a new timer if none is present.

```
          if (timeout !== Infinity) {
```

            self._endTimers[sound._id] = setTimeout(self._ended.bind(self, sound), timeout);

```
          }
```
```
 
```
```
          if (!internal) {
```
```
            setTimeout(function() {
```

              self._emit('play', sound._id);

```
              self._loadQueue();
```
```
            }, 0);
```
```
          }
```
```
        };
```
```
 
```

        if (Howler.state === 'running' && Howler.ctx.state !== 'interrupted') {

```
          playWebAudio();
```
```
        } else {
```
```
          self._playLock = true;
```
```
 
```

          // Wait for the audio context to resume before playing.

          self.once('resume', playWebAudio);

```
 
```
```
          // Cancel the end timer.
```
```
          self._clearTimer(sound._id);
```
```
        }
```
```
      } else {
```

        // Fire this when the sound is ready to play to begin HTML5 Audio playback.

```
        var playHtml5 = function() {
```
```
          node.currentTime = seek;
```

          node.muted = sound._muted || self._muted || Howler._muted || node.muted;

          node.volume = sound._volume * Howler.volume();

          node.playbackRate = sound._rate;

```
 
```

          // Some browsers will throw an error if this is called without user interaction.

```
          try {
```
```
            var play = node.play();
```
```
 
```

            // Support older browsers that don't support promises, and thus don't have this issue.

            if (play && typeof Promise !== 'undefined' && (play instanceof Promise || typeof play.then === 'function')) {

              // Implements a lock to prevent DOMException: The play() request was interrupted by a call to pause().

```
              self._playLock = true;
```
```
 
```

              // Set param values immediately.

```
              setParams();
```
```
 
```

              // Releases the lock and executes queued actions.

```
              play
```
```
                .then(function() {
```

                  self._playLock = false;

                  node._unlocked = true;

```
                  if (!internal) {
```

                    self._emit('play', sound._id);

```
                  } else {
```
```
                    self._loadQueue();
```
```
                  }
```
```
                })
```
```
                .catch(function() {
```

                  self._playLock = false;

                  self._emit('playerror', sound._id, 'Playback was unable to start. This is most commonly an issue ' +

                    'on mobile devices and Chrome where playback was not within a user interaction.');

```
 
```

                  // Reset the ended and paused values.

```
                  sound._ended = true;
```
```
                  sound._paused = true;
```
```
                });
```
```
            } else if (!internal) {
```
```
              self._playLock = false;
```
```
              setParams();
```

              self._emit('play', sound._id);

```
            }
```
```
 
```

            // Setting rate before playing won't work in IE, so we set it again here.

            node.playbackRate = sound._rate;

```
 
```

            // If the node is still paused, then we can assume there was a playback issue.

```
            if (node.paused) {
```

              self._emit('playerror', sound._id, 'Playback was unable to start. This is most commonly an issue ' +

                'on mobile devices and Chrome where playback was not within a user interaction.');

```
              return;
```
```
            }
```
```
 
```

            // Setup the end timer on sprites or listen for the ended event.

            if (sprite !== '__default' || sound._loop) {

              self._endTimers[sound._id] = setTimeout(self._ended.bind(self, sound), timeout);

```
            } else {
```

              self._endTimers[sound._id] = function() {

                // Fire ended on this audio node.

```
                self._ended(sound);
```
```
 
```
```
                // Clear this listener.
```

                node.removeEventListener('ended', self._endTimers[sound._id], false);

```
              };
```

              node.addEventListener('ended', self._endTimers[sound._id], false);

```
            }
```
```
          } catch (err) {
```

            self._emit('playerror', sound._id, err);

```
          }
```
```
        };
```
```
 
```

        // If this is streaming audio, make sure the src is set and load again.

        if (node.src === 'data:audio/wav;base64,UklGRigAAABXQVZFZm10IBIAAAABAAEARKwAAIhYAQACABAAAABkYXRhAgAAAAEA') {

```
          node.src = self._src;
```
```
          node.load();
```
```
        }
```
```
 
```

        // Play immediately if ready, or wait for the 'canplaythrough'e vent.

        var loadedNoReadyState = (window && window.ejecta) || (!node.readyState && Howler._navigator.isCocoonJS);

        if (node.readyState >= 3 || loadedNoReadyState) {

```
          playHtml5();
```
```
        } else {
```
```
          self._playLock = true;
```
```
          self._state = 'loading';
```
```
 
```
```
          var listener = function() {
```
```
            self._state = 'loaded';
```
```
 
```
```
            // Begin playback.
```
```
            playHtml5();
```
```
 
```
```
            // Clear this listener.
```

            node.removeEventListener(Howler._canPlayEvent, listener, false);

```
          };
```

          node.addEventListener(Howler._canPlayEvent, listener, false);

```
 
```
```
          // Cancel the end timer.
```
```
          self._clearTimer(sound._id);
```
```
        }
```
```
      }
```
```
 
```
```
      return sound._id;
```
```
    },
```
```
 
```
```
    /**
```

     * Pause playback and save current position.

     * @param  {Number} id The sound ID (empty to pause all in group).

```
     * @return {Howl}
```
```
     */
```
```
    pause: function(id) {
```
```
      var self = this;
```
```
 
```

      // If the sound hasn't loaded or a play() promise is pending, add it to the load queue to pause when capable.

      if (self._state !== 'loaded' || self._playLock) {

```
        self._queue.push({
```
```
          event: 'pause',
```
```
          action: function() {
```
```
            self.pause(id);
```
```
          }
```
```
        });
```
```
 
```
```
        return self;
```
```
      }
```
```
 
```

      // If no id is passed, get all ID's to be paused.

```
      var ids = self._getSoundIds(id);
```
```
 
```

      for (var i=0; i<ids.length; i++) {

```
        // Clear the end timer.
```
```
        self._clearTimer(ids[i]);
```
```
 
```
```
        // Get the sound.
```

        var sound = self._soundById(ids[i]);

```
 
```
```
        if (sound && !sound._paused) {
```
```
          // Reset the seek position.
```

          sound._seek = self.seek(ids[i]);

```
          sound._rateSeek = 0;
```
```
          sound._paused = true;
```
```
 
```

          // Stop currently running fades.

```
          self._stopFade(ids[i]);
```
```
 
```
```
          if (sound._node) {
```
```
            if (self._webAudio) {
```

              // Make sure the sound has been created.

              if (!sound._node.bufferSource) {

```
                continue;
```
```
              }
```
```
 
```

              if (typeof sound._node.bufferSource.stop === 'undefined') {

                sound._node.bufferSource.noteOff(0);

```
              } else {
```

                sound._node.bufferSource.stop(0);

```
              }
```
```
 
```

              // Clean up the buffer source.

              self._cleanBuffer(sound._node);

            } else if (!isNaN(sound._node.duration) || sound._node.duration === Infinity) {

```
              sound._node.pause();
```
```
            }
```
```
          }
```
```
        }
```
```
 
```

        // Fire the pause event, unless `true` is passed as the 2nd argument.

```
        if (!arguments[1]) {
```

          self._emit('pause', sound ? sound._id : null);

```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Stop playback and reset to start.

     * @param  {Number} id The sound ID (empty to stop all in group).

     * @param  {Boolean} internal Internal Use: true prevents event firing.

```
     * @return {Howl}
```
```
     */
```
```
    stop: function(id, internal) {
```
```
      var self = this;
```
```
 
```

      // If the sound hasn't loaded, add it to the load queue to stop when capable.

      if (self._state !== 'loaded' || self._playLock) {

```
        self._queue.push({
```
```
          event: 'stop',
```
```
          action: function() {
```
```
            self.stop(id);
```
```
          }
```
```
        });
```
```
 
```
```
        return self;
```
```
      }
```
```
 
```

      // If no id is passed, get all ID's to be stopped.

```
      var ids = self._getSoundIds(id);
```
```
 
```

      for (var i=0; i<ids.length; i++) {

```
        // Clear the end timer.
```
```
        self._clearTimer(ids[i]);
```
```
 
```
```
        // Get the sound.
```

        var sound = self._soundById(ids[i]);

```
 
```
```
        if (sound) {
```
```
          // Reset the seek position.
```

          sound._seek = sound._start || 0;

```
          sound._rateSeek = 0;
```
```
          sound._paused = true;
```
```
          sound._ended = true;
```
```
 
```

          // Stop currently running fades.

```
          self._stopFade(ids[i]);
```
```
 
```
```
          if (sound._node) {
```
```
            if (self._webAudio) {
```

              // Make sure the sound's AudioBufferSourceNode has been created.

              if (sound._node.bufferSource) {

                if (typeof sound._node.bufferSource.stop === 'undefined') {

                  sound._node.bufferSource.noteOff(0);

```
                } else {
```

                  sound._node.bufferSource.stop(0);

```
                }
```
```
 
```

                // Clean up the buffer source.

                self._cleanBuffer(sound._node);

```
              }
```

            } else if (!isNaN(sound._node.duration) || sound._node.duration === Infinity) {

              sound._node.currentTime = sound._start || 0;

```
              sound._node.pause();
```
```
 
```

              // If this is a live stream, stop download once the audio is stopped.

              if (sound._node.duration === Infinity) {

                self._clearSound(sound._node);

```
              }
```
```
            }
```
```
          }
```
```
 
```
```
          if (!internal) {
```

            self._emit('stop', sound._id);

```
          }
```
```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Mute/unmute a single sound or all sounds in this Howl group.

     * @param  {Boolean} muted Set to true to mute and false to unmute.

     * @param  {Number} id    The sound ID to update (omit to mute/unmute all).

```
     * @return {Howl}
```
```
     */
```
```
    mute: function(muted, id) {
```
```
      var self = this;
```
```
 
```

      // If the sound hasn't loaded, add it to the load queue to mute when capable.

      if (self._state !== 'loaded'|| self._playLock) {

```
        self._queue.push({
```
```
          event: 'mute',
```
```
          action: function() {
```
```
            self.mute(muted, id);
```
```
          }
```
```
        });
```
```
 
```
```
        return self;
```
```
      }
```
```
 
```

      // If applying mute/unmute to all sounds, update the group's value.

```
      if (typeof id === 'undefined') {
```

        if (typeof muted === 'boolean') {

```
          self._muted = muted;
```
```
        } else {
```
```
          return self._muted;
```
```
        }
```
```
      }
```
```
 
```

      // If no id is passed, get all ID's to be muted.

```
      var ids = self._getSoundIds(id);
```
```
 
```

      for (var i=0; i<ids.length; i++) {

```
        // Get the sound.
```

        var sound = self._soundById(ids[i]);

```
 
```
```
        if (sound) {
```
```
          sound._muted = muted;
```
```
 
```

          // Cancel active fade and set the volume to the end value.

```
          if (sound._interval) {
```
```
            self._stopFade(sound._id);
```
```
          }
```
```
 
```

          if (self._webAudio && sound._node) {

            sound._node.gain.setValueAtTime(muted ? 0 : sound._volume, Howler.ctx.currentTime);

```
          } else if (sound._node) {
```

            sound._node.muted = Howler._muted ? true : muted;

```
          }
```
```
 
```

          self._emit('mute', sound._id);

```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Get/set the volume of this sound or of the Howl group. This method can optionally take 0, 1 or 2 arguments.

     *   volume() -> Returns the group's volume value.

     *   volume(id) -> Returns the sound id's current volume.

     *   volume(vol) -> Sets the volume of all sounds in this Howl group.

     *   volume(vol, id) -> Sets the volume of passed sound id.

     * @return {Howl/Number} Returns self or current volume.

```
     */
```
```
    volume: function() {
```
```
      var self = this;
```
```
      var args = arguments;
```
```
      var vol, id;
```
```
 
```

      // Determine the values based on arguments.

```
      if (args.length === 0) {
```

        // Return the value of the groups' volume.

```
        return self._volume;
```

      } else if (args.length === 1 || args.length === 2 && typeof args[1] === 'undefined') {

        // First check if this is an ID, and if not, assume it is a new volume.

```
        var ids = self._getSoundIds();
```

        var index = ids.indexOf(args[0]);

```
        if (index >= 0) {
```
```
          id = parseInt(args[0], 10);
```
```
        } else {
```
```
          vol = parseFloat(args[0]);
```
```
        }
```
```
      } else if (args.length >= 2) {
```
```
        vol = parseFloat(args[0]);
```
```
        id = parseInt(args[1], 10);
```
```
      }
```
```
 
```

      // Update the volume or return the current volume.

```
      var sound;
```

      if (typeof vol !== 'undefined' && vol >= 0 && vol <= 1) {

        // If the sound hasn't loaded, add it to the load queue to change volume when capable.

        if (self._state !== 'loaded'|| self._playLock) {

```
          self._queue.push({
```
```
            event: 'volume',
```
```
            action: function() {
```

              self.volume.apply(self, args);

```
            }
```
```
          });
```
```
 
```
```
          return self;
```
```
        }
```
```
 
```
```
        // Set the group volume.
```

        if (typeof id === 'undefined') {

```
          self._volume = vol;
```
```
        }
```
```
 
```
```
        // Update one or all volumes.
```
```
        id = self._getSoundIds(id);
```

        for (var i=0; i<id.length; i++) {

```
          // Get the sound.
```

          sound = self._soundById(id[i]);

```
 
```
```
          if (sound) {
```
```
            sound._volume = vol;
```
```
 
```

            // Stop currently running fades.

```
            if (!args[2]) {
```
```
              self._stopFade(id[i]);
```
```
            }
```
```
 
```

            if (self._webAudio && sound._node && !sound._muted) {

              sound._node.gain.setValueAtTime(vol, Howler.ctx.currentTime);

            } else if (sound._node && !sound._muted) {

              sound._node.volume = vol * Howler.volume();

```
            }
```
```
 
```

            self._emit('volume', sound._id);

```
          }
```
```
        }
```
```
      } else {
```

        sound = id ? self._soundById(id) : self._sounds[0];

        return sound ? sound._volume : 0;

```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Fade a currently playing sound between two volumes (if no id is passed, all sounds will fade).

     * @param  {Number} from The value to fade from (0.0 to 1.0).

     * @param  {Number} to   The volume to fade to (0.0 to 1.0).

     * @param  {Number} len  Time in milliseconds to fade.

     * @param  {Number} id   The sound id (omit to fade all sounds).

```
     * @return {Howl}
```
```
     */
```
```
    fade: function(from, to, len, id) {
```
```
      var self = this;
```
```
 
```

      // If the sound hasn't loaded, add it to the load queue to fade when capable.

      if (self._state !== 'loaded' || self._playLock) {

```
        self._queue.push({
```
```
          event: 'fade',
```
```
          action: function() {
```

            self.fade(from, to, len, id);

```
          }
```
```
        });
```
```
 
```
```
        return self;
```
```
      }
```
```
 
```

      // Make sure the to/from/len values are numbers.

      from = Math.min(Math.max(0, parseFloat(from)), 1);

      to = Math.min(Math.max(0, parseFloat(to)), 1);

```
      len = parseFloat(len);
```
```
 
```

      // Set the volume to the start position.

```
      self.volume(from, id);
```
```
 
```

      // Fade the volume of one or all sounds.

```
      var ids = self._getSoundIds(id);
```

      for (var i=0; i<ids.length; i++) {

```
        // Get the sound.
```

        var sound = self._soundById(ids[i]);

```
 
```

        // Create a linear fade or fall back to timeouts with HTML5 Audio.

```
        if (sound) {
```

          // Stop the previous fade if no sprite is being used (otherwise, volume handles this).

```
          if (!id) {
```
```
            self._stopFade(ids[i]);
```
```
          }
```
```
 
```

          // If we are using Web Audio, let the native methods do the actual fade.

          if (self._webAudio && !sound._muted) {

            var currentTime = Howler.ctx.currentTime;

            var end = currentTime + (len / 1000);

```
            sound._volume = from;
```

            sound._node.gain.setValueAtTime(from, currentTime);

            sound._node.gain.linearRampToValueAtTime(to, end);

```
          }
```
```
 
```

          self._startFadeInterval(sound, from, to, len, ids[i], typeof id === 'undefined');

```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Starts the internal interval to fade a sound.

     * @param  {Object} sound Reference to sound to fade.

     * @param  {Number} from The value to fade from (0.0 to 1.0).

     * @param  {Number} to   The volume to fade to (0.0 to 1.0).

     * @param  {Number} len  Time in milliseconds to fade.

     * @param  {Number} id   The sound id to fade.

     * @param  {Boolean} isGroup   If true, set the volume on the group.

```
     */
```

    _startFadeInterval: function(sound, from, to, len, id, isGroup) {

```
      var self = this;
```
```
      var vol = from;
```
```
      var diff = to - from;
```

      var steps = Math.abs(diff / 0.01);

      var stepLen = Math.max(4, (steps > 0) ? len / steps : len);

```
      var lastTick = Date.now();
```
```
 
```

      // Store the value being faded to.

```
      sound._fadeTo = to;
```
```
 
```

      // Update the volume value on each interval tick.

      sound._interval = setInterval(function() {

        // Update the volume based on the time since the last tick.

        var tick = (Date.now() - lastTick) / len;

```
        lastTick = Date.now();
```
```
        vol += diff * tick;
```
```
 
```

        // Round to within 2 decimal points.

        vol = Math.round(vol * 100) / 100;

```
 
```

        // Make sure the volume is in the right bounds.

```
        if (diff < 0) {
```
```
          vol = Math.max(to, vol);
```
```
        } else {
```
```
          vol = Math.min(to, vol);
```
```
        }
```
```
 
```
```
        // Change the volume.
```
```
        if (self._webAudio) {
```
```
          sound._volume = vol;
```
```
        } else {
```

          self.volume(vol, sound._id, true);

```
        }
```
```
 
```
```
        // Set the group's volume.
```
```
        if (isGroup) {
```
```
          self._volume = vol;
```
```
        }
```
```
 
```

        // When the fade is complete, stop it and fire event.

        if ((to < from && vol <= to) || (to > from && vol >= to)) {

          clearInterval(sound._interval);

```
          sound._interval = null;
```
```
          sound._fadeTo = null;
```
```
          self.volume(to, sound._id);
```

          self._emit('fade', sound._id);

```
        }
```
```
      }, stepLen);
```
```
    },
```
```
 
```
```
    /**
```

     * Internal method that stops the currently playing fade when

     * a new fade starts, volume is changed or the sound is stopped.

     * @param  {Number} id The sound id.

```
     * @return {Howl}
```
```
     */
```
```
    _stopFade: function(id) {
```
```
      var self = this;
```
```
      var sound = self._soundById(id);
```
```
 
```
```
      if (sound && sound._interval) {
```
```
        if (self._webAudio) {
```

          sound._node.gain.cancelScheduledValues(Howler.ctx.currentTime);

```
        }
```
```
 
```
```
        clearInterval(sound._interval);
```
```
        sound._interval = null;
```
```
        self.volume(sound._fadeTo, id);
```
```
        sound._fadeTo = null;
```
```
        self._emit('fade', id);
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Get/set the loop parameter on a sound. This method can optionally take 0, 1 or 2 arguments.

     *   loop() -> Returns the group's loop value.

     *   loop(id) -> Returns the sound id's loop value.

     *   loop(loop) -> Sets the loop value for all sounds in this Howl group.

     *   loop(loop, id) -> Sets the loop value of passed sound id.

     * @return {Howl/Boolean} Returns self or current loop value.

```
     */
```
```
    loop: function() {
```
```
      var self = this;
```
```
      var args = arguments;
```
```
      var loop, id, sound;
```
```
 
```

      // Determine the values for loop and id.

```
      if (args.length === 0) {
```

        // Return the grou's loop value.

```
        return self._loop;
```
```
      } else if (args.length === 1) {
```

        if (typeof args[0] === 'boolean') {

```
          loop = args[0];
```
```
          self._loop = loop;
```
```
        } else {
```

          // Return this sound's loop value.

          sound = self._soundById(parseInt(args[0], 10));

          return sound ? sound._loop : false;

```
        }
```
```
      } else if (args.length === 2) {
```
```
        loop = args[0];
```
```
        id = parseInt(args[1], 10);
```
```
      }
```
```
 
```

      // If no id is passed, get all ID's to be looped.

```
      var ids = self._getSoundIds(id);
```

      for (var i=0; i<ids.length; i++) {

        sound = self._soundById(ids[i]);

```
 
```
```
        if (sound) {
```
```
          sound._loop = loop;
```

          if (self._webAudio && sound._node && sound._node.bufferSource) {

            sound._node.bufferSource.loop = loop;

```
            if (loop) {
```

              sound._node.bufferSource.loopStart = sound._start || 0;

              sound._node.bufferSource.loopEnd = sound._stop;

```
 
```

              // If playing, restart playback to ensure looping updates.

              if (self.playing(ids[i])) {

                self.pause(ids[i], true);

                self.play(ids[i], true);

```
              }
```
```
            }
```
```
          }
```
```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Get/set the playback rate of a sound. This method can optionally take 0, 1 or 2 arguments.

     *   rate() -> Returns the first sound node's current playback rate.

     *   rate(id) -> Returns the sound id's current playback rate.

     *   rate(rate) -> Sets the playback rate of all sounds in this Howl group.

     *   rate(rate, id) -> Sets the playback rate of passed sound id.

     * @return {Howl/Number} Returns self or the current playback rate.

```
     */
```
```
    rate: function() {
```
```
      var self = this;
```
```
      var args = arguments;
```
```
      var rate, id;
```
```
 
```

      // Determine the values based on arguments.

```
      if (args.length === 0) {
```

        // We will simply return the current rate of the first node.

```
        id = self._sounds[0]._id;
```
```
      } else if (args.length === 1) {
```

        // First check if this is an ID, and if not, assume it is a new rate value.

```
        var ids = self._getSoundIds();
```

        var index = ids.indexOf(args[0]);

```
        if (index >= 0) {
```
```
          id = parseInt(args[0], 10);
```
```
        } else {
```
```
          rate = parseFloat(args[0]);
```
```
        }
```
```
      } else if (args.length === 2) {
```
```
        rate = parseFloat(args[0]);
```
```
        id = parseInt(args[1], 10);
```
```
      }
```
```
 
```

      // Update the playback rate or return the current value.

```
      var sound;
```
```
      if (typeof rate === 'number') {
```

        // If the sound hasn't loaded, add it to the load queue to change playback rate when capable.

        if (self._state !== 'loaded' || self._playLock) {

```
          self._queue.push({
```
```
            event: 'rate',
```
```
            action: function() {
```

              self.rate.apply(self, args);

```
            }
```
```
          });
```
```
 
```
```
          return self;
```
```
        }
```
```
 
```
```
        // Set the group rate.
```

        if (typeof id === 'undefined') {

```
          self._rate = rate;
```
```
        }
```
```
 
```
```
        // Update one or all volumes.
```
```
        id = self._getSoundIds(id);
```

        for (var i=0; i<id.length; i++) {

```
          // Get the sound.
```

          sound = self._soundById(id[i]);

```
 
```
```
          if (sound) {
```

            // Keep track of our position when the rate changed and update the playback

            // start position so we can properly adjust the seek position for time elapsed.

```
            if (self.playing(id[i])) {
```

              sound._rateSeek = self.seek(id[i]);

              sound._playStart = self._webAudio ? Howler.ctx.currentTime : sound._playStart;

```
            }
```
```
            sound._rate = rate;
```
```
 
```

            // Change the playback rate.

            if (self._webAudio && sound._node && sound._node.bufferSource) {

              sound._node.bufferSource.playbackRate.setValueAtTime(rate, Howler.ctx.currentTime);

```
            } else if (sound._node) {
```

              sound._node.playbackRate = rate;

```
            }
```
```
 
```
```
            // Reset the timers.
```

            var seek = self.seek(id[i]);

            var duration = ((self._sprite[sound._sprite][0] + self._sprite[sound._sprite][1]) / 1000) - seek;

            var timeout = (duration * 1000) / Math.abs(sound._rate);

```
 
```

            // Start a new end timer if sound is already playing.

            if (self._endTimers[id[i]] || !sound._paused) {

```
              self._clearTimer(id[i]);
```

              self._endTimers[id[i]] = setTimeout(self._ended.bind(self, sound), timeout);

```
            }
```
```
 
```

            self._emit('rate', sound._id);

```
          }
```
```
        }
```
```
      } else {
```
```
        sound = self._soundById(id);
```

        return sound ? sound._rate : self._rate;

```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Get/set the seek position of a sound. This method can optionally take 0, 1 or 2 arguments.

     *   seek() -> Returns the first sound node's current seek position.

     *   seek(id) -> Returns the sound id's current seek position.

     *   seek(seek) -> Sets the seek position of the first sound node.

     *   seek(seek, id) -> Sets the seek position of passed sound id.

     * @return {Howl/Number} Returns self or the current seek position.

```
     */
```
```
    seek: function() {
```
```
      var self = this;
```
```
      var args = arguments;
```
```
      var seek, id;
```
```
 
```

      // Determine the values based on arguments.

```
      if (args.length === 0) {
```

        // We will simply return the current position of the first node.

```
        if (self._sounds.length) {
```
```
          id = self._sounds[0]._id;
```
```
        }
```
```
      } else if (args.length === 1) {
```

        // First check if this is an ID, and if not, assume it is a new seek position.

```
        var ids = self._getSoundIds();
```

        var index = ids.indexOf(args[0]);

```
        if (index >= 0) {
```
```
          id = parseInt(args[0], 10);
```

        } else if (self._sounds.length) {

```
          id = self._sounds[0]._id;
```
```
          seek = parseFloat(args[0]);
```
```
        }
```
```
      } else if (args.length === 2) {
```
```
        seek = parseFloat(args[0]);
```
```
        id = parseInt(args[1], 10);
```
```
      }
```
```
 
```
```
      // If there is no ID, bail out.
```
```
      if (typeof id === 'undefined') {
```
```
        return 0;
```
```
      }
```
```
 
```

      // If the sound hasn't loaded, add it to the load queue to seek when capable.

      if (typeof seek === 'number' && (self._state !== 'loaded' || self._playLock)) {

```
        self._queue.push({
```
```
          event: 'seek',
```
```
          action: function() {
```

            self.seek.apply(self, args);

```
          }
```
```
        });
```
```
 
```
```
        return self;
```
```
      }
```
```
 
```
```
      // Get the sound.
```
```
      var sound = self._soundById(id);
```
```
 
```
```
      if (sound) {
```

        if (typeof seek === 'number' && seek >= 0) {

          // Pause the sound and update position for restarting playback.

          var playing = self.playing(id);

```
          if (playing) {
```
```
            self.pause(id, true);
```
```
          }
```
```
 
```

          // Move the position of the track and cancel timer.

```
          sound._seek = seek;
```
```
          sound._ended = false;
```
```
          self._clearTimer(id);
```
```
 
```

          // Update the seek position for HTML5 Audio.

          if (!self._webAudio && sound._node && !isNaN(sound._node.duration)) {

            sound._node.currentTime = seek;

```
          }
```
```
 
```
```
          // Seek and emit when ready.
```

          var seekAndEmit = function() {

            // Restart the playback if the sound was playing.

```
            if (playing) {
```
```
              self.play(id, true);
```
```
            }
```
```
 
```
```
            self._emit('seek', id);
```
```
          };
```
```
 
```

          // Wait for the play lock to be unset before emitting (HTML5 Audio).

          if (playing && !self._webAudio) {

```
            var emitSeek = function() {
```
```
              if (!self._playLock) {
```
```
                seekAndEmit();
```
```
              } else {
```

                setTimeout(emitSeek, 0);

```
              }
```
```
            };
```
```
            setTimeout(emitSeek, 0);
```
```
          } else {
```
```
            seekAndEmit();
```
```
          }
```
```
        } else {
```
```
          if (self._webAudio) {
```

            var realTime = self.playing(id) ? Howler.ctx.currentTime - sound._playStart : 0;

            var rateSeek = sound._rateSeek ? sound._rateSeek - sound._seek : 0;

            return sound._seek + (rateSeek + realTime * Math.abs(sound._rate));

```
          } else {
```

            return sound._node.currentTime;

```
          }
```
```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Check if a specific sound is currently playing or not (if id is provided), or check if at least one of the sounds in the group is playing or not.

     * @param  {Number}  id The sound id to check. If none is passed, the whole sound group is checked.

     * @return {Boolean} True if playing and false if not.

```
     */
```
```
    playing: function(id) {
```
```
      var self = this;
```
```
 
```

      // Check the passed sound ID (if any).

```
      if (typeof id === 'number') {
```

        var sound = self._soundById(id);

        return sound ? !sound._paused : false;

```
      }
```
```
 
```

      // Otherwise, loop through all sounds and check if any are playing.

      for (var i=0; i<self._sounds.length; i++) {

```
        if (!self._sounds[i]._paused) {
```
```
          return true;
```
```
        }
```
```
      }
```
```
 
```
```
      return false;
```
```
    },
```
```
 
```
```
    /**
```

     * Get the duration of this sound. Passing a sound id will return the sprite duration.

     * @param  {Number} id The sound id to check. If none is passed, return full source duration.

     * @return {Number} Audio duration in seconds.

```
     */
```
```
    duration: function(id) {
```
```
      var self = this;
```
```
      var duration = self._duration;
```
```
 
```

      // If we pass an ID, get the sound and return the sprite length.

```
      var sound = self._soundById(id);
```
```
      if (sound) {
```

        duration = self._sprite[sound._sprite][1] / 1000;

```
      }
```
```
 
```
```
      return duration;
```
```
    },
```
```
 
```
```
    /**
```

     * Returns the current loaded state of this Howl.

     * @return {String} 'unloaded', 'loading', 'loaded'

```
     */
```
```
    state: function() {
```
```
      return this._state;
```
```
    },
```
```
 
```
```
    /**
```

     * Unload and destroy the current Howl object.

     * This will immediately stop all sound instances attached to this group.

```
     */
```
```
    unload: function() {
```
```
      var self = this;
```
```
 
```

      // Stop playing any active sounds.

```
      var sounds = self._sounds;
```

      for (var i=0; i<sounds.length; i++) {

        // Stop the sound if it is currently playing.

```
        if (!sounds[i]._paused) {
```
```
          self.stop(sounds[i]._id);
```
```
        }
```
```
 
```

        // Remove the source or disconnect.

```
        if (!self._webAudio) {
```

          // Set the source to 0-second silence to stop any downloading (except in IE).

          self._clearSound(sounds[i]._node);

```
 
```

          // Remove any event listeners.

          sounds[i]._node.removeEventListener('error', sounds[i]._errorFn, false);

          sounds[i]._node.removeEventListener(Howler._canPlayEvent, sounds[i]._loadFn, false);

          sounds[i]._node.removeEventListener('ended', sounds[i]._endFn, false);

```
 
```

          // Release the Audio object back to the pool.

          Howler._releaseHtml5Audio(sounds[i]._node);

```
        }
```
```
 
```
```
        // Empty out all of the nodes.
```
```
        delete sounds[i]._node;
```
```
 
```

        // Make sure all timers are cleared out.

        self._clearTimer(sounds[i]._id);

```
      }
```
```
 
```

      // Remove the references in the global Howler object.

      var index = Howler._howls.indexOf(self);

```
      if (index >= 0) {
```
```
        Howler._howls.splice(index, 1);
```
```
      }
```
```
 
```

      // Delete this sound from the cache (if no other Howl is using it).

```
      var remCache = true;
```

      for (i=0; i<Howler._howls.length; i++) {

        if (Howler._howls[i]._src === self._src || self._src.indexOf(Howler._howls[i]._src) >= 0) {

```
          remCache = false;
```
```
          break;
```
```
        }
```
```
      }
```
```
 
```
```
      if (cache && remCache) {
```
```
        delete cache[self._src];
```
```
      }
```
```
 
```
```
      // Clear global errors.
```
```
      Howler.noAudio = false;
```
```
 
```
```
      // Clear out `self`.
```
```
      self._state = 'unloaded';
```
```
      self._sounds = [];
```
```
      self = null;
```
```
 
```
```
      return null;
```
```
    },
```
```
 
```
```
    /**
```
```
     * Listen to a custom event.
```

     * @param  {String}   event Event name.

     * @param  {Function} fn    Listener to call.

     * @param  {Number}   id    (optional) Only listen to events for this sound.

     * @param  {Number}   once  (INTERNAL) Marks event to fire only once.

```
     * @return {Howl}
```
```
     */
```
```
    on: function(event, fn, id, once) {
```
```
      var self = this;
```
```
      var events = self['_on' + event];
```
```
 
```
```
      if (typeof fn === 'function') {
```

        events.push(once ? {id: id, fn: fn, once: once} : {id: id, fn: fn});

```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Remove a custom event. Call without parameters to remove all events.

     * @param  {String}   event Event name.

     * @param  {Function} fn    Listener to remove. Leave empty to remove all.

     * @param  {Number}   id    (optional) Only remove events for this sound.

```
     * @return {Howl}
```
```
     */
```
```
    off: function(event, fn, id) {
```
```
      var self = this;
```
```
      var events = self['_on' + event];
```
```
      var i = 0;
```
```
 
```

      // Allow passing just an event and ID.

```
      if (typeof fn === 'number') {
```
```
        id = fn;
```
```
        fn = null;
```
```
      }
```
```
 
```
```
      if (fn || id) {
```

        // Loop through event store and remove the passed function.

        for (i=0; i<events.length; i++) {

          var isId = (id === events[i].id);

          if (fn === events[i].fn && isId || !fn && isId) {

```
            events.splice(i, 1);
```
```
            break;
```
```
          }
```
```
        }
```
```
      } else if (event) {
```

        // Clear out all events of this type.

```
        self['_on' + event] = [];
```
```
      } else {
```

        // Clear out all events of every type.

```
        var keys = Object.keys(self);
```
```
        for (i=0; i<keys.length; i++) {
```

          if ((keys[i].indexOf('_on') === 0) && Array.isArray(self[keys[i]])) {

```
            self[keys[i]] = [];
```
```
          }
```
```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Listen to a custom event and remove it once fired.

     * @param  {String}   event Event name.

     * @param  {Function} fn    Listener to call.

     * @param  {Number}   id    (optional) Only listen to events for this sound.

```
     * @return {Howl}
```
```
     */
```
```
    once: function(event, fn, id) {
```
```
      var self = this;
```
```
 
```
```
      // Setup the event listener.
```
```
      self.on(event, fn, id, 1);
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Emit all events of a specific type and pass the sound id.

     * @param  {String} event Event name.

     * @param  {Number} id    Sound ID.

     * @param  {Number} msg   Message to go with event.

```
     * @return {Howl}
```
```
     */
```
```
    _emit: function(event, id, msg) {
```
```
      var self = this;
```
```
      var events = self['_on' + event];
```
```
 
```

      // Loop through event store and fire all functions.

      for (var i=events.length-1; i>=0; i--) {

        // Only fire the listener if the correct ID is used.

        if (!events[i].id || events[i].id === id || event === 'load') {

```
          setTimeout(function(fn) {
```
```
            fn.call(this, id, msg);
```

          }.bind(self, events[i].fn), 0);

```
 
```

          // If this event was setup with `once`, remove it.

```
          if (events[i].once) {
```

            self.off(event, events[i].fn, events[i].id);

```
          }
```
```
        }
```
```
      }
```
```
 
```

      // Pass the event type into load queue so that it can continue stepping.

```
      self._loadQueue(event);
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Queue of actions initiated before the sound has loaded.

     * These will be called in sequence, with the next only firing

     * after the previous has finished executing (even if async like play).

```
     * @return {Howl}
```
```
     */
```
```
    _loadQueue: function(event) {
```
```
      var self = this;
```
```
 
```
```
      if (self._queue.length > 0) {
```
```
        var task = self._queue[0];
```
```
 
```

        // Remove this task if a matching event was passed.

```
        if (task.event === event) {
```
```
          self._queue.shift();
```
```
          self._loadQueue();
```
```
        }
```
```
 
```

        // Run the task if no event type is passed.

```
        if (!event) {
```
```
          task.action();
```
```
        }
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Fired when playback ends at the end of the duration.

     * @param  {Sound} sound The sound object to work with.

```
     * @return {Howl}
```
```
     */
```
```
    _ended: function(sound) {
```
```
      var self = this;
```
```
      var sprite = sound._sprite;
```
```
 
```

      // If we are using IE and there was network latency we may be clipping

      // audio before it completes playing. Lets check the node to make sure it

      // believes it has completed, before ending the playback.

      if (!self._webAudio && sound._node && !sound._node.paused && !sound._node.ended && sound._node.currentTime < sound._stop) {

        setTimeout(self._ended.bind(self, sound), 100);

```
        return self;
```
```
      }
```
```
 
```
```
      // Should this sound loop?
```

      var loop = !!(sound._loop || self._sprite[sprite][2]);

```
 
```
```
      // Fire the ended event.
```
```
      self._emit('end', sound._id);
```
```
 
```

      // Restart the playback for HTML5 Audio loop.

```
      if (!self._webAudio && loop) {
```

        self.stop(sound._id, true).play(sound._id);

```
      }
```
```
 
```

      // Restart this timer if on a Web Audio loop.

```
      if (self._webAudio && loop) {
```
```
        self._emit('play', sound._id);
```

        sound._seek = sound._start || 0;

```
        sound._rateSeek = 0;
```

        sound._playStart = Howler.ctx.currentTime;

```
 
```

        var timeout = ((sound._stop - sound._start) * 1000) / Math.abs(sound._rate);

        self._endTimers[sound._id] = setTimeout(self._ended.bind(self, sound), timeout);

```
      }
```
```
 
```
```
      // Mark the node as paused.
```
```
      if (self._webAudio && !loop) {
```
```
        sound._paused = true;
```
```
        sound._ended = true;
```

        sound._seek = sound._start || 0;

```
        sound._rateSeek = 0;
```
```
        self._clearTimer(sound._id);
```
```
 
```
```
        // Clean up the buffer source.
```
```
        self._cleanBuffer(sound._node);
```
```
 
```

        // Attempt to auto-suspend AudioContext if no sounds are still playing.

```
        Howler._autoSuspend();
```
```
      }
```
```
 
```

      // When using a sprite, end the track.

```
      if (!self._webAudio && !loop) {
```
```
        self.stop(sound._id, true);
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Clear the end timer for a sound playback.

     * @param  {Number} id The sound ID.

```
     * @return {Howl}
```
```
     */
```
```
    _clearTimer: function(id) {
```
```
      var self = this;
```
```
 
```
```
      if (self._endTimers[id]) {
```

        // Clear the timeout or remove the ended listener.

        if (typeof self._endTimers[id] !== 'function') {

          clearTimeout(self._endTimers[id]);

```
        } else {
```

          var sound = self._soundById(id);

```
          if (sound && sound._node) {
```

            sound._node.removeEventListener('ended', self._endTimers[id], false);

```
          }
```
```
        }
```
```
 
```
```
        delete self._endTimers[id];
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Return the sound identified by this ID, or return null.

```
     * @param  {Number} id Sound ID
```

     * @return {Object}    Sound object or null.

```
     */
```
```
    _soundById: function(id) {
```
```
      var self = this;
```
```
 
```

      // Loop through all sounds and find the one with this ID.

      for (var i=0; i<self._sounds.length; i++) {

        if (id === self._sounds[i]._id) {

```
          return self._sounds[i];
```
```
        }
```
```
      }
```
```
 
```
```
      return null;
```
```
    },
```
```
 
```
```
    /**
```

     * Return an inactive sound from the pool or create a new one.

     * @return {Sound} Sound playback object.

```
     */
```
```
    _inactiveSound: function() {
```
```
      var self = this;
```
```
 
```
```
      self._drain();
```
```
 
```

      // Find the first inactive node to recycle.

      for (var i=0; i<self._sounds.length; i++) {

```
        if (self._sounds[i]._ended) {
```

          return self._sounds[i].reset();

```
        }
```
```
      }
```
```
 
```

      // If no inactive node was found, create a new one.

```
      return new Sound(self);
```
```
    },
```
```
 
```
```
    /**
```

     * Drain excess inactive sounds from the pool.

```
     */
```
```
    _drain: function() {
```
```
      var self = this;
```
```
      var limit = self._pool;
```
```
      var cnt = 0;
```
```
      var i = 0;
```
```
 
```

      // If there are less sounds than the max pool size, we are done.

      if (self._sounds.length < limit) {

```
        return;
```
```
      }
```
```
 
```

      // Count the number of inactive sounds.

      for (i=0; i<self._sounds.length; i++) {

```
        if (self._sounds[i]._ended) {
```
```
          cnt++;
```
```
        }
```
```
      }
```
```
 
```

      // Remove excess inactive sounds, going in reverse order.

      for (i=self._sounds.length - 1; i>=0; i--) {

```
        if (cnt <= limit) {
```
```
          return;
```
```
        }
```
```
 
```
```
        if (self._sounds[i]._ended) {
```

          // Disconnect the audio source when using Web Audio.

          if (self._webAudio && self._sounds[i]._node) {

            self._sounds[i]._node.disconnect(0);

```
          }
```
```
 
```

          // Remove sounds until we have the pool size.

```
          self._sounds.splice(i, 1);
```
```
          cnt--;
```
```
        }
```
```
      }
```
```
    },
```
```
 
```
```
    /**
```

     * Get all ID's from the sounds pool.

     * @param  {Number} id Only return one ID if one is passed.

     * @return {Array}    Array of IDs.

```
     */
```
```
    _getSoundIds: function(id) {
```
```
      var self = this;
```
```
 
```
```
      if (typeof id === 'undefined') {
```
```
        var ids = [];
```

        for (var i=0; i<self._sounds.length; i++) {

          ids.push(self._sounds[i]._id);

```
        }
```
```
 
```
```
        return ids;
```
```
      } else {
```
```
        return [id];
```
```
      }
```
```
    },
```
```
 
```
```
    /**
```

     * Load the sound back into the buffer source.

     * @param  {Sound} sound The sound object to work with.

```
     * @return {Howl}
```
```
     */
```
```
    _refreshBuffer: function(sound) {
```
```
      var self = this;
```
```
 
```

      // Setup the buffer source for playback.

      sound._node.bufferSource = Howler.ctx.createBufferSource();

      sound._node.bufferSource.buffer = cache[self._src];

```
 
```
```
      // Connect to the correct node.
```
```
      if (sound._panner) {
```

        sound._node.bufferSource.connect(sound._panner);

```
      } else {
```

        sound._node.bufferSource.connect(sound._node);

```
      }
```
```
 
```

      // Setup looping and playback rate.

      sound._node.bufferSource.loop = sound._loop;

```
      if (sound._loop) {
```

        sound._node.bufferSource.loopStart = sound._start || 0;

        sound._node.bufferSource.loopEnd = sound._stop || 0;

```
      }
```

      sound._node.bufferSource.playbackRate.setValueAtTime(sound._rate, Howler.ctx.currentTime);

```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Prevent memory leaks by cleaning up the buffer source after playback.

     * @param  {Object} node Sound's audio node containing the buffer source.

```
     * @return {Howl}
```
```
     */
```
```
    _cleanBuffer: function(node) {
```
```
      var self = this;
```

      var isIOS = Howler._navigator && Howler._navigator.vendor.indexOf('Apple') >= 0;

```
 
```

      if (Howler._scratchBuffer && node.bufferSource) {

        node.bufferSource.onended = null;

        node.bufferSource.disconnect(0);

```
        if (isIOS) {
```

          try { node.bufferSource.buffer = Howler._scratchBuffer; } catch(e) {}

```
        }
```
```
      }
```
```
      node.bufferSource = null;
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Set the source to a 0-second silence to stop any downloading (except in IE).

     * @param  {Object} node Audio node to clear.

```
     */
```
```
    _clearSound: function(node) {
```

      var checkIE = /MSIE |Trident\//.test(Howler._navigator && Howler._navigator.userAgent);

```
      if (!checkIE) {
```

        node.src = 'data:audio/wav;base64,UklGRigAAABXQVZFZm10IBIAAAABAAEARKwAAIhYAQACABAAAABkYXRhAgAAAAEA';

```
      }
```
```
    }
```
```
  };
```
```
 
```
```
  /** Single Sound Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```

   * Setup the sound object, which each node attached to a Howl group is contained in.

   * @param {Object} howl The Howl parent group.

```
   */
```
```
  var Sound = function(howl) {
```
```
    this._parent = howl;
```
```
    this.init();
```
```
  };
```
```
  Sound.prototype = {
```
```
    /**
```
```
     * Initialize a new Sound object.
```
```
     * @return {Sound}
```
```
     */
```
```
    init: function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```
```
 
```
```
      // Setup the default parameters.
```
```
      self._muted = parent._muted;
```
```
      self._loop = parent._loop;
```
```
      self._volume = parent._volume;
```
```
      self._rate = parent._rate;
```
```
      self._seek = 0;
```
```
      self._paused = true;
```
```
      self._ended = true;
```
```
      self._sprite = '__default';
```
```
 
```

      // Generate a unique ID for this sound.

```
      self._id = ++Howler._counter;
```
```
 
```

      // Add itself to the parent's pool.

```
      parent._sounds.push(self);
```
```
 
```
```
      // Create the new node.
```
```
      self.create();
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Create and setup a new sound object, whether HTML5 Audio or Web Audio.

```
     * @return {Sound}
```
```
     */
```
```
    create: function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```

      var volume = (Howler._muted || self._muted || self._parent._muted) ? 0 : self._volume;

```
 
```
```
      if (parent._webAudio) {
```

        // Create the gain node for controlling volume (the source will connect to this).

        self._node = (typeof Howler.ctx.createGain === 'undefined') ? Howler.ctx.createGainNode() : Howler.ctx.createGain();

        self._node.gain.setValueAtTime(volume, Howler.ctx.currentTime);

```
        self._node.paused = true;
```

        self._node.connect(Howler.masterGain);

```
      } else if (!Howler.noAudio) {
```

        // Get an unlocked Audio object from the pool.

        self._node = Howler._obtainHtml5Audio();

```
 
```

        // Listen for errors (http://dev.w3.org/html5/spec-author-view/spec.html#mediaerror).

        self._errorFn = self._errorListener.bind(self);

        self._node.addEventListener('error', self._errorFn, false);

```
 
```

        // Listen for 'canplaythrough' event to let us know the sound is ready.

        self._loadFn = self._loadListener.bind(self);

        self._node.addEventListener(Howler._canPlayEvent, self._loadFn, false);

```
 
```

        // Listen for the 'ended' event on the sound to account for edge-case where

        // a finite sound has a duration of Infinity.

        self._endFn = self._endListener.bind(self);

        self._node.addEventListener('ended', self._endFn, false);

```
 
```
```
        // Setup the new audio node.
```
```
        self._node.src = parent._src;
```

        self._node.preload = parent._preload === true ? 'auto' : parent._preload;

        self._node.volume = volume * Howler.volume();

```
 
```
```
        // Begin loading the source.
```
```
        self._node.load();
```
```
      }
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * Reset the parameters of this sound to the original state (for recycle).

```
     * @return {Sound}
```
```
     */
```
```
    reset: function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```
```
 
```

      // Reset all of the parameters of this sound.

```
      self._muted = parent._muted;
```
```
      self._loop = parent._loop;
```
```
      self._volume = parent._volume;
```
```
      self._rate = parent._rate;
```
```
      self._seek = 0;
```
```
      self._rateSeek = 0;
```
```
      self._paused = true;
```
```
      self._ended = true;
```
```
      self._sprite = '__default';
```
```
 
```

      // Generate a new ID so that it isn't confused with the previous sound.

```
      self._id = ++Howler._counter;
```
```
 
```
```
      return self;
```
```
    },
```
```
 
```
```
    /**
```

     * HTML5 Audio error listener callback.

```
     */
```
```
    _errorListener: function() {
```
```
      var self = this;
```
```
 
```

      // Fire an error event and pass back the code.

      self._parent._emit('loaderror', self._id, self._node.error ? self._node.error.code : 0);

```
 
```
```
      // Clear the event listener.
```

      self._node.removeEventListener('error', self._errorFn, false);

```
    },
```
```
 
```
```
    /**
```

     * HTML5 Audio canplaythrough listener callback.

```
     */
```
```
    _loadListener: function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```
```
 
```

      // Round up the duration to account for the lower precision in HTML5 Audio.

      parent._duration = Math.ceil(self._node.duration * 10) / 10;

```
 
```

      // Setup a sprite if none is defined.

      if (Object.keys(parent._sprite).length === 0) {

        parent._sprite = {__default: [0, parent._duration * 1000]};

```
      }
```
```
 
```
```
      if (parent._state !== 'loaded') {
```
```
        parent._state = 'loaded';
```
```
        parent._emit('load');
```
```
        parent._loadQueue();
```
```
      }
```
```
 
```
```
      // Clear the event listener.
```

      self._node.removeEventListener(Howler._canPlayEvent, self._loadFn, false);

```
    },
```
```
 
```
```
    /**
```

     * HTML5 Audio ended listener callback.

```
     */
```
```
    _endListener: function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```
```
 
```

      // Only handle the `ended`` event if the duration is Infinity.

      if (parent._duration === Infinity) {

        // Update the parent duration to match the real audio duration.

        // Round up the duration to account for the lower precision in HTML5 Audio.

        parent._duration = Math.ceil(self._node.duration * 10) / 10;

```
 
```

        // Update the sprite that corresponds to the real duration.

        if (parent._sprite.__default[1] === Infinity) {

          parent._sprite.__default[1] = parent._duration * 1000;

```
        }
```
```
 
```

        // Run the regular ended method.

```
        parent._ended(self);
```
```
      }
```
```
 
```

      // Clear the event listener since the duration is now correct.

      self._node.removeEventListener('ended', self._endFn, false);

```
    }
```
```
  };
```
```
 
```
```
  /** Helper Methods **/
```

  /***************************************************************************/

```
 
```
```
  var cache = {};
```
```
 
```
```
  /**
```

   * Buffer a sound from URL, Data URI or cache and decode to audio source (Web Audio API).

```
   * @param  {Howl} self
```
```
   */
```
```
  var loadBuffer = function(self) {
```
```
    var url = self._src;
```
```
 
```

    // Check if the buffer has already been cached and use it instead.

```
    if (cache[url]) {
```

      // Set the duration from the cache.

      self._duration = cache[url].duration;

```
 
```
```
      // Load the sound into this Howl.
```
```
      loadSound(self);
```
```
 
```
```
      return;
```
```
    }
```
```
 
```

    if (/^data:[^;]+;base64,/.test(url)) {

      // Decode the base64 data URI without XHR, since some browsers don't support it.

      var data = atob(url.split(',')[1]);

      var dataView = new Uint8Array(data.length);

      for (var i=0; i<data.length; ++i) {

        dataView[i] = data.charCodeAt(i);

```
      }
```
```
 
```

      decodeAudioData(dataView.buffer, self);

```
    } else {
```
```
      // Load the buffer from the URL.
```
```
      var xhr = new XMLHttpRequest();
```

      xhr.open(self._xhr.method, url, true);

      xhr.withCredentials = self._xhr.withCredentials;

```
      xhr.responseType = 'arraybuffer';
```
```
 
```

      // Apply any custom headers to the request.

```
      if (self._xhr.headers) {
```

        Object.keys(self._xhr.headers).forEach(function(key) {

          xhr.setRequestHeader(key, self._xhr.headers[key]);

```
        });
```
```
      }
```
```
 
```
```
      xhr.onload = function() {
```

        // Make sure we get a successful response back.

        var code = (xhr.status + '')[0];

        if (code !== '0' && code !== '2' && code !== '3') {

          self._emit('loaderror', null, 'Failed loading audio file with status: ' + xhr.status + '.');

```
          return;
```
```
        }
```
```
 
```

        decodeAudioData(xhr.response, self);

```
      };
```
```
      xhr.onerror = function() {
```

        // If there is an error, switch to HTML5 Audio.

```
        if (self._webAudio) {
```
```
          self._html5 = true;
```
```
          self._webAudio = false;
```
```
          self._sounds = [];
```
```
          delete cache[url];
```
```
          self.load();
```
```
        }
```
```
      };
```
```
      safeXhrSend(xhr);
```
```
    }
```
```
  };
```
```
 
```
```
  /**
```

   * Send the XHR request wrapped in a try/catch.

```
   * @param  {Object} xhr XHR to send.
```
```
   */
```
```
  var safeXhrSend = function(xhr) {
```
```
    try {
```
```
      xhr.send();
```
```
    } catch (e) {
```
```
      xhr.onerror();
```
```
    }
```
```
  };
```
```
 
```
```
  /**
```

   * Decode audio data from an array buffer.

   * @param  {ArrayBuffer} arraybuffer The audio data.

```
   * @param  {Howl}        self
```
```
   */
```

  var decodeAudioData = function(arraybuffer, self) {

    // Fire a load error if something broke.

```
    var error = function() {
```

      self._emit('loaderror', null, 'Decoding audio data failed.');

```
    };
```
```
 
```
```
    // Load the sound on success.
```
```
    var success = function(buffer) {
```

      if (buffer && self._sounds.length > 0) {

```
        cache[self._src] = buffer;
```
```
        loadSound(self, buffer);
```
```
      } else {
```
```
        error();
```
```
      }
```
```
    };
```
```
 
```

    // Decode the buffer into an audio source.

    if (typeof Promise !== 'undefined' && Howler.ctx.decodeAudioData.length === 1) {

      Howler.ctx.decodeAudioData(arraybuffer).then(success).catch(error);

```
    } else {
```

      Howler.ctx.decodeAudioData(arraybuffer, success, error);

```
    }
```
```
  }
```
```
 
```
```
  /**
```

   * Sound is now loaded, so finish setting everything up and fire the loaded event.

```
   * @param  {Howl} self
```

   * @param  {Object} buffer The decoded buffer sound source.

```
   */
```

  var loadSound = function(self, buffer) {

```
    // Set the duration.
```
```
    if (buffer && !self._duration) {
```
```
      self._duration = buffer.duration;
```
```
    }
```
```
 
```

    // Setup a sprite if none is defined.

    if (Object.keys(self._sprite).length === 0) {

      self._sprite = {__default: [0, self._duration * 1000]};

```
    }
```
```
 
```
```
    // Fire the loaded event.
```
```
    if (self._state !== 'loaded') {
```
```
      self._state = 'loaded';
```
```
      self._emit('load');
```
```
      self._loadQueue();
```
```
    }
```
```
  };
```
```
 
```
```
  /**
```

   * Setup the audio context when available, or switch to HTML5 Audio mode.

```
   */
```
```
  var setupAudioContext = function() {
```

    // If we have already detected that Web Audio isn't supported, don't run this step again.

```
    if (!Howler.usingWebAudio) {
```
```
      return;
```
```
    }
```
```
 
```

    // Check if we are using Web Audio and setup the AudioContext if we are.

```
    try {
```

      if (typeof AudioContext !== 'undefined') {

        Howler.ctx = new AudioContext();

      } else if (typeof webkitAudioContext !== 'undefined') {

        Howler.ctx = new webkitAudioContext();

```
      } else {
```
```
        Howler.usingWebAudio = false;
```
```
      }
```
```
    } catch(e) {
```
```
      Howler.usingWebAudio = false;
```
```
    }
```
```
 
```

    // If the audio context creation still failed, set using web audio to false.

```
    if (!Howler.ctx) {
```
```
      Howler.usingWebAudio = false;
```
```
    }
```
```
 
```

    // Check if a webview is being used on iOS8 or earlier (rather than the browser).

    // If it is, disable Web Audio as it causes crashing.

    var iOS = (/iP(hone|od|ad)/.test(Howler._navigator && Howler._navigator.platform));

    var appVersion = Howler._navigator && Howler._navigator.appVersion.match(/OS (\d+)_(\d+)_?(\d+)?/);

    var version = appVersion ? parseInt(appVersion[1], 10) : null;

    if (iOS && version && version < 9) {

      var safari = /safari/.test(Howler._navigator && Howler._navigator.userAgent.toLowerCase());

      if (Howler._navigator && !safari) {

```
        Howler.usingWebAudio = false;
```
```
      }
```
```
    }
```
```
 
```

    // Create and expose the master GainNode when using Web Audio (useful for plugins or advanced usage).

```
    if (Howler.usingWebAudio) {
```

      Howler.masterGain = (typeof Howler.ctx.createGain === 'undefined') ? Howler.ctx.createGainNode() : Howler.ctx.createGain();

      Howler.masterGain.gain.setValueAtTime(Howler._muted ? 0 : Howler._volume, Howler.ctx.currentTime);

      Howler.masterGain.connect(Howler.ctx.destination);

```
    }
```
```
 
```
```
    // Re-run the setup on Howler.
```
```
    Howler._setup();
```
```
  };
```
```
 
```

  // Add support for AMD (Asynchronous Module Definition) libraries such as require.js.

  if (typeof define === 'function' && define.amd) {

```
    define([], function() {
```
```
      return {
```
```
        Howler: Howler,
```
```
        Howl: Howl
```
```
      };
```
```
    });
```
```
  }
```
```
 
```

  // Add support for CommonJS libraries such as browserify.

```
  if (typeof exports !== 'undefined') {
```
```
    exports.Howler = Howler;
```
```
    exports.Howl = Howl;
```
```
  }
```
```
 
```

  // Add to global in Node.js (for testing, etc).

```
  if (typeof global !== 'undefined') {
```
```
    global.HowlerGlobal = HowlerGlobal;
```
```
    global.Howler = Howler;
```
```
    global.Howl = Howl;
```
```
    global.Sound = Sound;
```

  } else if (typeof window !== 'undefined') {  // Define globally in case AMD is not available or unused.

```
    window.HowlerGlobal = HowlerGlobal;
```
```
    window.Howler = Howler;
```
```
    window.Howl = Howl;
```
```
    window.Sound = Sound;
```
```
  }
```
```
})();
```
```
 
```
```
 
```
```
/*!
```

 *  Spatial Plugin - Adds support for stereo and 3D audio where Web Audio is supported.

```
 *  
```
```
 *  howler.js v2.2.3
```
```
 *  howlerjs.com
```
```
 *
```

 *  (c) 2013-2020, James Simpson of GoldFire Studios

```
 *  goldfirestudios.com
```
```
 *
```
```
 *  MIT License
```
```
 */
```
```
 
```
```
(function() {
```
```
 
```
```
  'use strict';
```
```
 
```
```
  // Setup default properties.
```

  HowlerGlobal.prototype._pos = [0, 0, 0];

  HowlerGlobal.prototype._orientation = [0, 0, -1, 0, 1, 0];

```
 
```
```
  /** Global Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```

   * Helper method to update the stereo panning position of all current Howls.

   * Future Howls will not use this value unless explicitly set.

   * @param  {Number} pan A value of -1.0 is all the way left and 1.0 is all the way right.

   * @return {Howler/Number}     Self or current stereo panning value.

```
   */
```

  HowlerGlobal.prototype.stereo = function(pan) {

```
    var self = this;
```
```
 
```

    // Stop right here if not using Web Audio.

    if (!self.ctx || !self.ctx.listener) {

```
      return self;
```
```
    }
```
```
 
```

    // Loop through all Howls and update their stereo panning.

    for (var i=self._howls.length-1; i>=0; i--) {

```
      self._howls[i].stereo(pan);
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /**
```

   * Get/set the position of the listener in 3D cartesian space. Sounds using

   * 3D position will be relative to the listener's position.

   * @param  {Number} x The x-position of the listener.

   * @param  {Number} y The y-position of the listener.

   * @param  {Number} z The z-position of the listener.

   * @return {Howler/Array}   Self or current listener position.

```
   */
```

  HowlerGlobal.prototype.pos = function(x, y, z) {

```
    var self = this;
```
```
 
```

    // Stop right here if not using Web Audio.

    if (!self.ctx || !self.ctx.listener) {

```
      return self;
```
```
    }
```
```
 
```

    // Set the defaults for optional 'y' & 'z'.

    y = (typeof y !== 'number') ? self._pos[1] : y;

    z = (typeof z !== 'number') ? self._pos[2] : z;

```
 
```
```
    if (typeof x === 'number') {
```
```
      self._pos = [x, y, z];
```
```
 
```

      if (typeof self.ctx.listener.positionX !== 'undefined') {

        self.ctx.listener.positionX.setTargetAtTime(self._pos[0], Howler.ctx.currentTime, 0.1);

        self.ctx.listener.positionY.setTargetAtTime(self._pos[1], Howler.ctx.currentTime, 0.1);

        self.ctx.listener.positionZ.setTargetAtTime(self._pos[2], Howler.ctx.currentTime, 0.1);

```
      } else {
```

        self.ctx.listener.setPosition(self._pos[0], self._pos[1], self._pos[2]);

```
      }
```
```
    } else {
```
```
      return self._pos;
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /**
```

   * Get/set the direction the listener is pointing in the 3D cartesian space.

   * A front and up vector must be provided. The front is the direction the

   * face of the listener is pointing, and up is the direction the top of the

   * listener is pointing. Thus, these values are expected to be at right angles

```
   * from each other.
```

   * @param  {Number} x   The x-orientation of the listener.

   * @param  {Number} y   The y-orientation of the listener.

   * @param  {Number} z   The z-orientation of the listener.

   * @param  {Number} xUp The x-orientation of the top of the listener.

   * @param  {Number} yUp The y-orientation of the top of the listener.

   * @param  {Number} zUp The z-orientation of the top of the listener.

   * @return {Howler/Array}     Returns self or the current orientation vectors.

```
   */
```

  HowlerGlobal.prototype.orientation = function(x, y, z, xUp, yUp, zUp) {

```
    var self = this;
```
```
 
```

    // Stop right here if not using Web Audio.

    if (!self.ctx || !self.ctx.listener) {

```
      return self;
```
```
    }
```
```
 
```

    // Set the defaults for optional 'y' & 'z'.

```
    var or = self._orientation;
```

    y = (typeof y !== 'number') ? or[1] : y;

    z = (typeof z !== 'number') ? or[2] : z;

    xUp = (typeof xUp !== 'number') ? or[3] : xUp;

    yUp = (typeof yUp !== 'number') ? or[4] : yUp;

    zUp = (typeof zUp !== 'number') ? or[5] : zUp;

```
 
```
```
    if (typeof x === 'number') {
```

      self._orientation = [x, y, z, xUp, yUp, zUp];

```
 
```

      if (typeof self.ctx.listener.forwardX !== 'undefined') {

        self.ctx.listener.forwardX.setTargetAtTime(x, Howler.ctx.currentTime, 0.1);

        self.ctx.listener.forwardY.setTargetAtTime(y, Howler.ctx.currentTime, 0.1);

        self.ctx.listener.forwardZ.setTargetAtTime(z, Howler.ctx.currentTime, 0.1);

        self.ctx.listener.upX.setTargetAtTime(xUp, Howler.ctx.currentTime, 0.1);

        self.ctx.listener.upY.setTargetAtTime(yUp, Howler.ctx.currentTime, 0.1);

        self.ctx.listener.upZ.setTargetAtTime(zUp, Howler.ctx.currentTime, 0.1);

```
      } else {
```

        self.ctx.listener.setOrientation(x, y, z, xUp, yUp, zUp);

```
      }
```
```
    } else {
```
```
      return or;
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /** Group Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```

   * Add new properties to the core init.

   * @param  {Function} _super Core init method.

```
   * @return {Howl}
```
```
   */
```

  Howl.prototype.init = (function(_super) {

```
    return function(o) {
```
```
      var self = this;
```
```
 
```

      // Setup user-defined default properties.

      self._orientation = o.orientation || [1, 0, 0];

```
      self._stereo = o.stereo || null;
```
```
      self._pos = o.pos || null;
```
```
      self._pannerAttr = {
```

        coneInnerAngle: typeof o.coneInnerAngle !== 'undefined' ? o.coneInnerAngle : 360,

        coneOuterAngle: typeof o.coneOuterAngle !== 'undefined' ? o.coneOuterAngle : 360,

        coneOuterGain: typeof o.coneOuterGain !== 'undefined' ? o.coneOuterGain : 0,

        distanceModel: typeof o.distanceModel !== 'undefined' ? o.distanceModel : 'inverse',

        maxDistance: typeof o.maxDistance !== 'undefined' ? o.maxDistance : 10000,

        panningModel: typeof o.panningModel !== 'undefined' ? o.panningModel : 'HRTF',

        refDistance: typeof o.refDistance !== 'undefined' ? o.refDistance : 1,

        rolloffFactor: typeof o.rolloffFactor !== 'undefined' ? o.rolloffFactor : 1

```
      };
```
```
 
```
```
      // Setup event listeners.
```

      self._onstereo = o.onstereo ? [{fn: o.onstereo}] : [];

      self._onpos = o.onpos ? [{fn: o.onpos}] : [];

      self._onorientation = o.onorientation ? [{fn: o.onorientation}] : [];

```
 
```

      // Complete initilization with howler.js core's init function.

```
      return _super.call(this, o);
```
```
    };
```
```
  })(Howl.prototype.init);
```
```
 
```
```
  /**
```

   * Get/set the stereo panning of the audio source for this sound or all in the group.

   * @param  {Number} pan  A value of -1.0 is all the way left and 1.0 is all the way right.

   * @param  {Number} id (optional) The sound ID. If none is passed, all in group will be updated.

   * @return {Howl/Number}    Returns self or the current stereo panning value.

```
   */
```

  Howl.prototype.stereo = function(pan, id) {

```
    var self = this;
```
```
 
```

    // Stop right here if not using Web Audio.

```
    if (!self._webAudio) {
```
```
      return self;
```
```
    }
```
```
 
```

    // If the sound hasn't loaded, add it to the load queue to change stereo pan when capable.

```
    if (self._state !== 'loaded') {
```
```
      self._queue.push({
```
```
        event: 'stereo',
```
```
        action: function() {
```
```
          self.stereo(pan, id);
```
```
        }
```
```
      });
```
```
 
```
```
      return self;
```
```
    }
```
```
 
```

    // Check for PannerStereoNode support and fallback to PannerNode if it doesn't exist.

    var pannerType = (typeof Howler.ctx.createStereoPanner === 'undefined') ? 'spatial' : 'stereo';

```
 
```

    // Setup the group's stereo panning if no ID is passed.

```
    if (typeof id === 'undefined') {
```

      // Return the group's stereo panning if no parameters are passed.

```
      if (typeof pan === 'number') {
```
```
        self._stereo = pan;
```
```
        self._pos = [pan, 0, 0];
```
```
      } else {
```
```
        return self._stereo;
```
```
      }
```
```
    }
```
```
 
```

    // Change the streo panning of one or all sounds in group.

```
    var ids = self._getSoundIds(id);
```
```
    for (var i=0; i<ids.length; i++) {
```
```
      // Get the sound.
```

      var sound = self._soundById(ids[i]);

```
 
```
```
      if (sound) {
```
```
        if (typeof pan === 'number') {
```
```
          sound._stereo = pan;
```
```
          sound._pos = [pan, 0, 0];
```
```
 
```
```
          if (sound._node) {
```

            // If we are falling back, make sure the panningModel is equalpower.

            sound._pannerAttr.panningModel = 'equalpower';

```
 
```

            // Check if there is a panner setup and create a new one if not.

            if (!sound._panner || !sound._panner.pan) {

              setupPanner(sound, pannerType);

```
            }
```
```
 
```

            if (pannerType === 'spatial') {

              if (typeof sound._panner.positionX !== 'undefined') {

                sound._panner.positionX.setValueAtTime(pan, Howler.ctx.currentTime);

                sound._panner.positionY.setValueAtTime(0, Howler.ctx.currentTime);

                sound._panner.positionZ.setValueAtTime(0, Howler.ctx.currentTime);

```
              } else {
```

                sound._panner.setPosition(pan, 0, 0);

```
              }
```
```
            } else {
```

              sound._panner.pan.setValueAtTime(pan, Howler.ctx.currentTime);

```
            }
```
```
          }
```
```
 
```

          self._emit('stereo', sound._id);

```
        } else {
```
```
          return sound._stereo;
```
```
        }
```
```
      }
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /**
```

   * Get/set the 3D spatial position of the audio source for this sound or group relative to the global listener.

   * @param  {Number} x  The x-position of the audio source.

   * @param  {Number} y  The y-position of the audio source.

   * @param  {Number} z  The z-position of the audio source.

   * @param  {Number} id (optional) The sound ID. If none is passed, all in group will be updated.

   * @return {Howl/Array}    Returns self or the current 3D spatial position: [x, y, z].

```
   */
```

  Howl.prototype.pos = function(x, y, z, id) {

```
    var self = this;
```
```
 
```

    // Stop right here if not using Web Audio.

```
    if (!self._webAudio) {
```
```
      return self;
```
```
    }
```
```
 
```

    // If the sound hasn't loaded, add it to the load queue to change position when capable.

```
    if (self._state !== 'loaded') {
```
```
      self._queue.push({
```
```
        event: 'pos',
```
```
        action: function() {
```
```
          self.pos(x, y, z, id);
```
```
        }
```
```
      });
```
```
 
```
```
      return self;
```
```
    }
```
```
 
```

    // Set the defaults for optional 'y' & 'z'.

    y = (typeof y !== 'number') ? 0 : y;

    z = (typeof z !== 'number') ? -0.5 : z;

```
 
```

    // Setup the group's spatial position if no ID is passed.

```
    if (typeof id === 'undefined') {
```

      // Return the group's spatial position if no parameters are passed.

```
      if (typeof x === 'number') {
```
```
        self._pos = [x, y, z];
```
```
      } else {
```
```
        return self._pos;
```
```
      }
```
```
    }
```
```
 
```

    // Change the spatial position of one or all sounds in group.

```
    var ids = self._getSoundIds(id);
```
```
    for (var i=0; i<ids.length; i++) {
```
```
      // Get the sound.
```

      var sound = self._soundById(ids[i]);

```
 
```
```
      if (sound) {
```
```
        if (typeof x === 'number') {
```
```
          sound._pos = [x, y, z];
```
```
 
```
```
          if (sound._node) {
```

            // Check if there is a panner setup and create a new one if not.

            if (!sound._panner || sound._panner.pan) {

              setupPanner(sound, 'spatial');

```
            }
```
```
 
```

            if (typeof sound._panner.positionX !== 'undefined') {

              sound._panner.positionX.setValueAtTime(x, Howler.ctx.currentTime);

              sound._panner.positionY.setValueAtTime(y, Howler.ctx.currentTime);

              sound._panner.positionZ.setValueAtTime(z, Howler.ctx.currentTime);

```
            } else {
```

              sound._panner.setPosition(x, y, z);

```
            }
```
```
          }
```
```
 
```
```
          self._emit('pos', sound._id);
```
```
        } else {
```
```
          return sound._pos;
```
```
        }
```
```
      }
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /**
```

   * Get/set the direction the audio source is pointing in the 3D cartesian coordinate

   * space. Depending on how direction the sound is, based on the `cone` attributes,

   * a sound pointing away from the listener can be quiet or silent.

   * @param  {Number} x  The x-orientation of the source.

   * @param  {Number} y  The y-orientation of the source.

   * @param  {Number} z  The z-orientation of the source.

   * @param  {Number} id (optional) The sound ID. If none is passed, all in group will be updated.

   * @return {Howl/Array}    Returns self or the current 3D spatial orientation: [x, y, z].

```
   */
```

  Howl.prototype.orientation = function(x, y, z, id) {

```
    var self = this;
```
```
 
```

    // Stop right here if not using Web Audio.

```
    if (!self._webAudio) {
```
```
      return self;
```
```
    }
```
```
 
```

    // If the sound hasn't loaded, add it to the load queue to change orientation when capable.

```
    if (self._state !== 'loaded') {
```
```
      self._queue.push({
```
```
        event: 'orientation',
```
```
        action: function() {
```

          self.orientation(x, y, z, id);

```
        }
```
```
      });
```
```
 
```
```
      return self;
```
```
    }
```
```
 
```

    // Set the defaults for optional 'y' & 'z'.

    y = (typeof y !== 'number') ? self._orientation[1] : y;

    z = (typeof z !== 'number') ? self._orientation[2] : z;

```
 
```

    // Setup the group's spatial orientation if no ID is passed.

```
    if (typeof id === 'undefined') {
```

      // Return the group's spatial orientation if no parameters are passed.

```
      if (typeof x === 'number') {
```
```
        self._orientation = [x, y, z];
```
```
      } else {
```
```
        return self._orientation;
```
```
      }
```
```
    }
```
```
 
```

    // Change the spatial orientation of one or all sounds in group.

```
    var ids = self._getSoundIds(id);
```
```
    for (var i=0; i<ids.length; i++) {
```
```
      // Get the sound.
```

      var sound = self._soundById(ids[i]);

```
 
```
```
      if (sound) {
```
```
        if (typeof x === 'number') {
```

          sound._orientation = [x, y, z];

```
 
```
```
          if (sound._node) {
```

            // Check if there is a panner setup and create a new one if not.

```
            if (!sound._panner) {
```

              // Make sure we have a position to setup the node with.

```
              if (!sound._pos) {
```

                sound._pos = self._pos || [0, 0, -0.5];

```
              }
```
```
 
```

              setupPanner(sound, 'spatial');

```
            }
```
```
 
```

            if (typeof sound._panner.orientationX !== 'undefined') {

              sound._panner.orientationX.setValueAtTime(x, Howler.ctx.currentTime);

              sound._panner.orientationY.setValueAtTime(y, Howler.ctx.currentTime);

              sound._panner.orientationZ.setValueAtTime(z, Howler.ctx.currentTime);

```
            } else {
```

              sound._panner.setOrientation(x, y, z);

```
            }
```
```
          }
```
```
 
```

          self._emit('orientation', sound._id);

```
        } else {
```
```
          return sound._orientation;
```
```
        }
```
```
      }
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /**
```

   * Get/set the panner node's attributes for a sound or group of sounds.

   * This method can optionall take 0, 1 or 2 arguments.

   *   pannerAttr() -> Returns the group's values.

   *   pannerAttr(id) -> Returns the sound id's values.

   *   pannerAttr(o) -> Set's the values of all sounds in this Howl group.

   *   pannerAttr(o, id) -> Set's the values of passed sound id.

```
   *
```
```
   *   Attributes:
```

   *     coneInnerAngle - (360 by default) A parameter for directional audio sources, this is an angle, in degrees,

   *                      inside of which there will be no volume reduction.

   *     coneOuterAngle - (360 by default) A parameter for directional audio sources, this is an angle, in degrees,

   *                      outside of which the volume will be reduced to a constant value of `coneOuterGain`.

   *     coneOuterGain - (0 by default) A parameter for directional audio sources, this is the gain outside of the

   *                     `coneOuterAngle`. It is a linear value in the range `[0, 1]`.

   *     distanceModel - ('inverse' by default) Determines algorithm used to reduce volume as audio moves away from

   *                     listener. Can be `linear`, `inverse` or `exponential.

   *     maxDistance - (10000 by default) The maximum distance between source and listener, after which the volume

   *                   will not be reduced any further.

   *     refDistance - (1 by default) A reference distance for reducing volume as source moves further from the listener.

   *                   This is simply a variable of the distance model and has a different effect depending on which model

   *                   is used and the scale of your coordinates. Generally, volume will be equal to 1 at this distance.

   *     rolloffFactor - (1 by default) How quickly the volume reduces as source moves from listener. This is simply a

   *                     variable of the distance model and can be in the range of `[0, 1]` with `linear` and `[0, ∞]`

   *                     with `inverse` and `exponential`.

   *     panningModel - ('HRTF' by default) Determines which spatialization algorithm is used to position audio.

   *                     Can be `HRTF` or `equalpower`.

```
   *
```

   * @return {Howl/Object} Returns self or current panner attributes.

```
   */
```

  Howl.prototype.pannerAttr = function() {

```
    var self = this;
```
```
    var args = arguments;
```
```
    var o, id, sound;
```
```
 
```

    // Stop right here if not using Web Audio.

```
    if (!self._webAudio) {
```
```
      return self;
```
```
    }
```
```
 
```

    // Determine the values based on arguments.

```
    if (args.length === 0) {
```

      // Return the group's panner attribute values.

```
      return self._pannerAttr;
```
```
    } else if (args.length === 1) {
```

      if (typeof args[0] === 'object') {

```
        o = args[0];
```
```
 
```

        // Set the grou's panner attribute values.

        if (typeof id === 'undefined') {

```
          if (!o.pannerAttr) {
```
```
            o.pannerAttr = {
```

              coneInnerAngle: o.coneInnerAngle,

              coneOuterAngle: o.coneOuterAngle,

              coneOuterGain: o.coneOuterGain,

              distanceModel: o.distanceModel,

              maxDistance: o.maxDistance,

              refDistance: o.refDistance,

              rolloffFactor: o.rolloffFactor,

              panningModel: o.panningModel

```
            };
```
```
          }
```
```
 
```
```
          self._pannerAttr = {
```

            coneInnerAngle: typeof o.pannerAttr.coneInnerAngle !== 'undefined' ? o.pannerAttr.coneInnerAngle : self._coneInnerAngle,

            coneOuterAngle: typeof o.pannerAttr.coneOuterAngle !== 'undefined' ? o.pannerAttr.coneOuterAngle : self._coneOuterAngle,

            coneOuterGain: typeof o.pannerAttr.coneOuterGain !== 'undefined' ? o.pannerAttr.coneOuterGain : self._coneOuterGain,

            distanceModel: typeof o.pannerAttr.distanceModel !== 'undefined' ? o.pannerAttr.distanceModel : self._distanceModel,

            maxDistance: typeof o.pannerAttr.maxDistance !== 'undefined' ? o.pannerAttr.maxDistance : self._maxDistance,

            refDistance: typeof o.pannerAttr.refDistance !== 'undefined' ? o.pannerAttr.refDistance : self._refDistance,

            rolloffFactor: typeof o.pannerAttr.rolloffFactor !== 'undefined' ? o.pannerAttr.rolloffFactor : self._rolloffFactor,

            panningModel: typeof o.pannerAttr.panningModel !== 'undefined' ? o.pannerAttr.panningModel : self._panningModel

```
          };
```
```
        }
```
```
      } else {
```

        // Return this sound's panner attribute values.

        sound = self._soundById(parseInt(args[0], 10));

        return sound ? sound._pannerAttr : self._pannerAttr;

```
      }
```
```
    } else if (args.length === 2) {
```
```
      o = args[0];
```
```
      id = parseInt(args[1], 10);
```
```
    }
```
```
 
```

    // Update the values of the specified sounds.

```
    var ids = self._getSoundIds(id);
```
```
    for (var i=0; i<ids.length; i++) {
```
```
      sound = self._soundById(ids[i]);
```
```
 
```
```
      if (sound) {
```

        // Merge the new values into the sound.

```
        var pa = sound._pannerAttr;
```
```
        pa = {
```

          coneInnerAngle: typeof o.coneInnerAngle !== 'undefined' ? o.coneInnerAngle : pa.coneInnerAngle,

          coneOuterAngle: typeof o.coneOuterAngle !== 'undefined' ? o.coneOuterAngle : pa.coneOuterAngle,

          coneOuterGain: typeof o.coneOuterGain !== 'undefined' ? o.coneOuterGain : pa.coneOuterGain,

          distanceModel: typeof o.distanceModel !== 'undefined' ? o.distanceModel : pa.distanceModel,

          maxDistance: typeof o.maxDistance !== 'undefined' ? o.maxDistance : pa.maxDistance,

          refDistance: typeof o.refDistance !== 'undefined' ? o.refDistance : pa.refDistance,

          rolloffFactor: typeof o.rolloffFactor !== 'undefined' ? o.rolloffFactor : pa.rolloffFactor,

          panningModel: typeof o.panningModel !== 'undefined' ? o.panningModel : pa.panningModel

```
        };
```
```
 
```

        // Update the panner values or create a new panner if none exists.

```
        var panner = sound._panner;
```
```
        if (panner) {
```

          panner.coneInnerAngle = pa.coneInnerAngle;

          panner.coneOuterAngle = pa.coneOuterAngle;

          panner.coneOuterGain = pa.coneOuterGain;

          panner.distanceModel = pa.distanceModel;

          panner.maxDistance = pa.maxDistance;

          panner.refDistance = pa.refDistance;

          panner.rolloffFactor = pa.rolloffFactor;

          panner.panningModel = pa.panningModel;

```
        } else {
```

          // Make sure we have a position to setup the node with.

```
          if (!sound._pos) {
```

            sound._pos = self._pos || [0, 0, -0.5];

```
          }
```
```
 
```
```
          // Create a new panner node.
```

          setupPanner(sound, 'spatial');

```
        }
```
```
      }
```
```
    }
```
```
 
```
```
    return self;
```
```
  };
```
```
 
```
```
  /** Single Sound Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```

   * Add new properties to the core Sound init.

   * @param  {Function} _super Core Sound init method.

```
   * @return {Sound}
```
```
   */
```

  Sound.prototype.init = (function(_super) {

```
    return function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```
```
 
```

      // Setup user-defined default properties.

      self._orientation = parent._orientation;

```
      self._stereo = parent._stereo;
```
```
      self._pos = parent._pos;
```

      self._pannerAttr = parent._pannerAttr;

```
 
```

      // Complete initilization with howler.js core Sound's init function.

```
      _super.call(this);
```
```
 
```

      // If a stereo or position was specified, set it up.

```
      if (self._stereo) {
```
```
        parent.stereo(self._stereo);
```
```
      } else if (self._pos) {
```

        parent.pos(self._pos[0], self._pos[1], self._pos[2], self._id);

```
      }
```
```
    };
```
```
  })(Sound.prototype.init);
```
```
 
```
```
  /**
```

   * Override the Sound.reset method to clean up properties from the spatial plugin.

   * @param  {Function} _super Sound reset method.

```
   * @return {Sound}
```
```
   */
```

  Sound.prototype.reset = (function(_super) {

```
    return function() {
```
```
      var self = this;
```
```
      var parent = self._parent;
```
```
 
```

      // Reset all spatial plugin properties on this sound.

      self._orientation = parent._orientation;

```
      self._stereo = parent._stereo;
```
```
      self._pos = parent._pos;
```

      self._pannerAttr = parent._pannerAttr;

```
 
```

      // If a stereo or position was specified, set it up.

```
      if (self._stereo) {
```
```
        parent.stereo(self._stereo);
```
```
      } else if (self._pos) {
```

        parent.pos(self._pos[0], self._pos[1], self._pos[2], self._id);

```
      } else if (self._panner) {
```
```
        // Disconnect the panner.
```
```
        self._panner.disconnect(0);
```
```
        self._panner = undefined;
```
```
        parent._refreshBuffer(self);
```
```
      }
```
```
 
```

      // Complete resetting of the sound.

```
      return _super.call(this);
```
```
    };
```
```
  })(Sound.prototype.reset);
```
```
 
```
```
  /** Helper Methods **/
```

  /***************************************************************************/

```
 
```
```
  /**
```

   * Create a new panner node and save it on the sound.

   * @param  {Sound} sound Specific sound to setup panning on.

   * @param {String} type Type of panner to create: 'stereo' or 'spatial'.

```
   */
```

  var setupPanner = function(sound, type) {

```
    type = type || 'spatial';
```
```
 
```
```
    // Create the new panner node.
```
```
    if (type === 'spatial') {
```

      sound._panner = Howler.ctx.createPanner();

      sound._panner.coneInnerAngle = sound._pannerAttr.coneInnerAngle;

      sound._panner.coneOuterAngle = sound._pannerAttr.coneOuterAngle;

      sound._panner.coneOuterGain = sound._pannerAttr.coneOuterGain;

      sound._panner.distanceModel = sound._pannerAttr.distanceModel;

      sound._panner.maxDistance = sound._pannerAttr.maxDistance;

      sound._panner.refDistance = sound._pannerAttr.refDistance;

      sound._panner.rolloffFactor = sound._pannerAttr.rolloffFactor;

      sound._panner.panningModel = sound._pannerAttr.panningModel;

```
 
```

      if (typeof sound._panner.positionX !== 'undefined') {

        sound._panner.positionX.setValueAtTime(sound._pos[0], Howler.ctx.currentTime);

        sound._panner.positionY.setValueAtTime(sound._pos[1], Howler.ctx.currentTime);

        sound._panner.positionZ.setValueAtTime(sound._pos[2], Howler.ctx.currentTime);

```
      } else {
```

        sound._panner.setPosition(sound._pos[0], sound._pos[1], sound._pos[2]);

```
      }
```
```
 
```

      if (typeof sound._panner.orientationX !== 'undefined') {

        sound._panner.orientationX.setValueAtTime(sound._orientation[0], Howler.ctx.currentTime);

        sound._panner.orientationY.setValueAtTime(sound._orientation[1], Howler.ctx.currentTime);

        sound._panner.orientationZ.setValueAtTime(sound._orientation[2], Howler.ctx.currentTime);

```
      } else {
```

        sound._panner.setOrientation(sound._orientation[0], sound._orientation[1], sound._orientation[2]);

```
      }
```
```
    } else {
```

      sound._panner = Howler.ctx.createStereoPanner();

      sound._panner.pan.setValueAtTime(sound._stereo, Howler.ctx.currentTime);

```
    }
```
```
 
```
```
    sound._panner.connect(sound._node);
```
```
 
```
```
    // Update the connections.
```
```
    if (!sound._paused) {
```

      sound._parent.pause(sound._id, true).play(sound._id, true);

```
    }
```
```
  };
```
```
})();
```
```
 
```