Sound effects in JavaScript / HTML5

user_224129 0
Viewed 299882

I'm using HTML5 to program games; the obstacle I've run into now is how to play sound effects.

The specific requirements are few in number:

  • Play and mix multiple sounds,
  • Play the same sample multiple times, possibly overlapping playbacks,
  • Interrupt playback of a sample at any point,
  • Preferably play WAV files containing (low quality) raw PCM, but I can convert these, of course.

My first approach was to use the HTML5 <audio> element and define all sound effects in my page. Firefox plays the WAV files just peachy, but calling #play multiple times doesn't really play the sample multiple times. From my understanding of the HTML5 spec, the <audio> element also tracks playback state, so that explains why.

My immediate thought was to clone the audio elements, so I created the following tiny JavaScript library to do that for me (depends on jQuery):

var Snd = {
  init: function() {
    $("audio").each(function() {
      var src = this.getAttribute('src');
      if (src.substring(0, 4) !== "snd/") { return; }
      // Cut out the basename (strip directory and extension)
      var name = src.substring(4, src.length - 4);
      // Create the helper function, which clones the audio object and plays it
      var Constructor = function() {};
      Constructor.prototype = this;
      Snd[name] = function() {
        var clone = new Constructor();
        clone.play();
        // Return the cloned element, so the caller can interrupt the sound effect
        return clone;
      };
    });
  }
};

So now I can do Snd.boom(); from the Firebug console and play snd/boom.wav, but I still can't play the same sample multiple times. It seems that the <audio> element is really more of a streaming feature rather than something to play sound effects with.

Is there a clever way to make this happen that I'm missing, preferably using only HTML5 and JavaScript?

I should also mention that, my test environment is Firefox 3.5 on Ubuntu 9.10. The other browsers I've tried - Opera, Midori, Chromium, Epiphany - produced varying results. Some don't play anything, and some throw exceptions.

html5-audio html javascript
18 Answers

HTML5 Audio objects

You don't need to bother with <audio> elements. HTML 5 lets you access Audio objects directly:

var snd = new Audio("file.wav"); // buffers automatically when created
snd.play();

There's no support for mixing in current version of the spec.

To play same sound multiple times, create multiple instances of the Audio object. You could also set snd.currentTime=0 on the object after it finishes playing.

Since the JS constructor doesn't support fallback <source> elements, you should use 

(new Audio()).canPlayType("audio/ogg; codecs=vorbis")

to test whether the browser supports Ogg Vorbis.

If you're writing a game or a music app (more than just a player), you'll want to use more advanced Web Audio API, which is now supported by most browsers.

user_270090

You may also want to use this to detect HTML 5 audio in some cases:

http://diveintohtml5.ep.io/everything.html

HTML 5 JS Detect function

function supportsAudio()
{
    var a = document.createElement('audio'); 
    return !!(a.canPlayType && a.canPlayType('audio/mpeg;').replace(/no/, ''));
}
user_633990

To play the same sample multiple times, wouldn't it be possible to do something like this:

e.pause(); // Perhaps optional
e.currentTime = 0;
e.play();

(e is the audio element)

Perhaps I completely misunderstood your problem, do you want the sound effect to play multiple times at the same time? Then this is completely wrong.

user_2042180

Have a look at the jai (-> mirror) (javascript audio interface) site. From looking at their source, they appear to be calling play() repeatedly, and they mention that their library might be appropriate for use in HTML5-based games.

You can fire multiple audio events simultaneously, which could be used for creating Javascript games, or having a voice speaking over some background music

user_817170

Sounds like what you want is multi-channel sounds. Let's suppose you have 4 channels (like on really old 16-bit games), I haven't got round to playing with the HTML5 audio feature yet, but don't you just need 4 <audio> elements, and cycle which is used to play the next sound effect? Have you tried that? What happens? If it works: To play more sounds simultaneously, just add more <audio> elements.

I have done this before without the HTML5 <audio> element, using a little Flash object from http://flash-mp3-player.net/ - I wrote a music quiz (http://webdeavour.appspot.com/) and used it to play clips of music when the user clicked the button for the question. Initially I had one player per question, and it was possible to play them over the top of each other, so I changed it so there was only one player, which I pointed at different music clips.

Lee_Kowalkowski_309450

It's not possible to do multi-shot playing with a single <audio> element. You need to use multiple elements for this.

user_784360 

var AudioContextFunc = window.AudioContext || window.webkitAudioContext;
var audioContext = new AudioContextFunc();
var player=new WebAudioFontPlayer();
var instrumVox,instrumApplause;
var drumClap,drumLowTom,drumHighTom,drumSnare,drumKick,drumCrash;
loadDrum(21,function(s){drumClap=s;});
loadDrum(30,function(s){drumLowTom=s;});
loadDrum(50,function(s){drumHighTom=s;});
loadDrum(15,function(s){drumSnare=s;});
loadDrum(5,function(s){drumKick=s;});
loadDrum(70,function(s){drumCrash=s;});
loadInstrument(594,function(s){instrumVox=s;});
loadInstrument(1367,function(s){instrumApplause=s;});
function loadDrum(n,callback){
  var info=player.loader.drumInfo(n);
  player.loader.startLoad(audioContext, info.url, info.variable);
  player.loader.waitLoad(function () {callback(window[info.variable])});
}
function loadInstrument(n,callback){
  var info=player.loader.instrumentInfo(n);
  player.loader.startLoad(audioContext, info.url, info.variable);
  player.loader.waitLoad(function () {callback(window[info.variable])});
}
function uhoh(){
  var when=audioContext.currentTime;
  var b=0.1;
  player.queueWaveTable(audioContext, audioContext.destination, instrumVox, when+b*0, 60, b*1);
  player.queueWaveTable(audioContext, audioContext.destination, instrumVox, when+b*3, 56, b*4);
}
function applause(){
  player.queueWaveTable(audioContext, audioContext.destination, instrumApplause, audioContext.currentTime, 54, 3);
}
function badumtss(){
  var when=audioContext.currentTime;
  var b=0.11;
  player.queueWaveTable(audioContext, audioContext.destination, drumSnare, when+b*0, drumSnare.zones[0].keyRangeLow, 3.5);
  player.queueWaveTable(audioContext, audioContext.destination, drumLowTom, when+b*0, drumLowTom.zones[0].keyRangeLow, 3.5);
  player.queueWaveTable(audioContext, audioContext.destination, drumSnare, when+b*1, drumSnare.zones[0].keyRangeLow, 3.5);
  player.queueWaveTable(audioContext, audioContext.destination, drumHighTom, when+b*1, drumHighTom.zones[0].keyRangeLow, 3.5);
  player.queueWaveTable(audioContext, audioContext.destination, drumSnare, when+b*3, drumSnare.zones[0].keyRangeLow, 3.5);
  player.queueWaveTable(audioContext, audioContext.destination, drumKick, when+b*3, drumKick.zones[0].keyRangeLow, 3.5);
  player.queueWaveTable(audioContext, audioContext.destination, drumCrash, when+b*3, drumCrash.zones[0].keyRangeLow, 3.5);
}
<script src='https://surikov.github.io/webaudiofont/npm/dist/WebAudioFontPlayer.js'></script>
<button onclick='badumtss();'>badumtss</button>
<button onclick='uhoh();'>uhoh</button>
<button onclick='applause();'>applause</button>
<br/><a href='https://github.com/surikov/webaudiofont'>More sounds</a>

user_3400120

Web Audio API is right tool for this job. There is little bit of work involved in loading sounds files and playing it. Luckily there are plenty of libraries out there that simplify the job. Being interested in sounds I also created a library called musquito you can check out that as well.

Currently it supports only fading sound effect and I'm working on other things like 3D spatialization.

user_7416160
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