javascriptweb-audio-apijavascript-oscillator

(Web Audio API) Oscillator node error: cannot call start more than once


When I start my oscillator, stop it, and then start it again; I get the following error:

Uncaught InvalidStateError: Failed to execute 'start' on 'OscillatorNode': cannot call start more than once.

Obviously I could use gain to "stop" the audio but that strikes me as poor practice. What's a more efficient way of stopping the oscillator while being able to start it again?

code (jsfiddle)

var ctx = new AudioContext();
var osc = ctx.createOscillator();

osc.frequency.value = 8000;

osc.connect(ctx.destination);

function startOsc(bool) {
    if(bool === undefined) bool = true;
    
    if(bool === true) {
        osc.start(ctx.currentTime);
    } else {
        osc.stop(ctx.currentTime);
    }
}

$(document).ready(function() {
    $("#start").click(function() {
       startOsc(); 
    });
    $("#stop").click(function() {
       startOsc(false); 
    });
});

Current solution (at time of question): http://jsfiddle.net/xbqbzgt2/2/

Final solution: http://jsfiddle.net/xbqbzgt2/3/


Solution

  • A better way would be to start the oscillatorNode once and connect/disconnect the oscillatorNode from the graph when needed, ie :

    var ctx = new AudioContext();
    var osc = ctx.createOscillator();   
    osc.frequency.value = 8000;    
    osc.start();    
    $(document).ready(function() {
        $("#start").click(function() {
             osc.connect(ctx.destination);
        });
        $("#stop").click(function() {
             osc.disconnect(ctx.destination);
        });
    });
    

    This how muting in done in muting the thermin (mozilla web audio api documentation)