Is there a way to use the Web Audio API to sample audio faster than real-time?

Question

I\'m playing around with the Web Audio API & trying to find a way to import an mp3 (so therefore this is only in Chrome), and generate a waveform of it on a canvas. I c

Answer 1

There is a really amazing 'offline' mode of the Web Audio API that allows you to pre-process an entire file through an audio context and then do something with the result:

var context = new webkitOfflineAudioContext();

var source = context.createBufferSource();
source.buffer = buffer;
source.connect(context.destination);
source.noteOn(0);

context.oncomplete = function(e) {
  var audioBuffer = e.renderedBuffer;
};

context.startRendering();

So the setup looks exactly the same as the real-time processing mode, except you set up the oncomplete callback and the call to startRendering(). What you get back in e.redneredBuffer is an AudioBuffer.