0

Background:

I am currently trying to create a frequency visualizer for music using Flash and AS3 (for a variety of reasons). I am completely new to AS3, somewhat new to Flash, but have a bit of background with javascript, which has helped a lot to get me to where I am at. Anyway, I have this code that I have modified from a tutorial for creating bars for the amplitude of each range of frequency.

However, because I want it to work first I used probably the least efficient way of calculating each bar.

The Code:

import flash.media.Sound;
import flash.net.URLRequest;
import flash.events.Event;
import flash.utils.ByteArray;
import flash.display.FrameLabel;

var s:Sound = new Sound(new URLRequest("Mix 1 v4.mp3"));
s.play(0, 1);

var ba:ByteArray = new ByteArray();

addEventListener(Event.ENTER_FRAME, loop);
function loop(e:Event):void {
    graphics.clear();
    graphics.beginFill(0xFFFF00);
    graphics.drawRect(0, 502, 1280, 4);
    SoundMixer.computeSpectrum(ba, true);
    for (var i:uint=0; i<256; i+=8) {
        if (i<=8) {
        var num:Number = -ba.readFloat()*250;
        graphics.beginFill(0xFFFF00);
        graphics.drawRect(110, 500, 32, num);
        }
        if (i>8 && i<=16) {...

And the code continues increasing each if statement by 8 and each drawRect(110(34*x), 500...)

What I am looking for is a way to make the computeSpectrum and ByteArray "global" and have the graphics automatically drawn for each section of frequency values, instead of having 32 instances of if (i>32 && i<=40) {...

All in all, this code works. But it is most definitely not correct, at least from my limited experience (I imagine it will probably make some of you cringe.)

I realize there is probably a way to simplify it, but it is hard to figure out where to start, and is frustrating to debug when you don't know what you are doing (I'm sure we have all been there at one point)

I will work at coming up with my own solution, but I would be extremely happy with some guidance on this issue.

Thanks

G-Schmu
  • 27
  • 7
  • computeSpectrum method works off of global sounds not just the mp3 playing. I would suggest scrapping this completely and look into this. http://www.marinbezhanov.com/web-development/14/actionscript-3-sound-extract-demystified-or-how-to-draw-a-waveform-in-flash/ – The_asMan Apr 08 '14 at 21:17
  • I appreciate the suggestion, but it is not quite what I am looking for (at least as far as I could tell from my brief look through all the links). I want a real-time representation of each frequency. Basically I am trying to emulate _[this](https://www.youtube.com/watch?v=nA6rz9KQElQ)_, with more control. – G-Schmu Apr 09 '14 at 00:03
  • My point is the code is there. How you represent/graph the data is up to you. You said you are new to AS3 so again I would suggest you take that code and modify it to work the way you want it. – The_asMan Apr 09 '14 at 15:10
  • You dont need to control the results. If the sound has low treble why rig the results to make it look higher than heard? Visuals should match ears. Also with computeSpectrum consider the visual difference between setting `FFT = ` true vs false (time vs freq domains). And yes, lose the `if` statements (unnecessary calculations) – VC.One Apr 09 '14 at 21:24

1 Answers1

0

This doesn't make sense:

for (var i:uint=0; i<256; i+=8) {
    if (i<=8) ...
    if (i>8 && i<=16) ...

You don't need the if statments, you know what i is on each go around the loop, so you can simplify this to: 

for (var i:uint=0; i<256; i+=8)
{
    var index = (i / 8);//or bitshift using i >> 3
    var num:Number = -ba.readFloat()*250;
    graphics.beginFill(0xFFFF00);
    graphics.drawRect(110 + (index * 32), 500, 32, num);
}
DFreeman
  • 542
  • 6
  • 13
  • I knew it was going to be something simple like that. I thought I had tried doing something similar, but when I tried to do it for some reason it wasn't taking the next part of the Float for each bar. Thanks. – G-Schmu Apr 11 '14 at 02:00