Jacksonkr Jacksonkr - 1 month ago 15
Javascript Question

(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/

Answer

The best solution I've found so far is to keep the SAME audioContext while recreating the oscillator every time you need to use it.

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

FYI You can only create 6 audioContext objects per browser page lifespan (or at least per my hardware):

Uncaught NotSupportedError: Failed to construct 'AudioContext': The number of hardware contexts provided (6) is greater than or equal to the maximum bound (6).
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