Animation while playing audio in HTML5

Question

I have a flash player programmed by a different team. Now I have 1 project where I need to re program that player into HTML5. All functions of the flash player looks doable. I am just not sure how to show the animation when audio is being played. Eg. When beats get high, the animation shows up more when there is a bit silence the animation show up less. Could anybody please help me?

To get an idea, here is the attached screenshot:

Answer 1

With SoundManager2 you can easily access waveform data and make a graphical display with it:

someSoundObject.whileplaying = function() {
  // Move 256 absolutely-positioned 1x1-pixel DIVs, for example (ugly, but works)
  var gPixels = document.getElementById('graphPixels').getElementsByTagName('div');
  var gScale = 32; // draw -32 to +32px from "zero" (i.e., center Y-axis point)
  for (var i=0; i<256; i++) {
    graphPixels[i].style.top = (gScale+Math.ceil(this.waveformData.left[i]*-gScale))+'px';
  }
}

http://www.schillmania.com/projects/soundmanager2/doc/