Flash 创建声音波形图象

//创建位图数据
var bmpData:BitmapData = new BitmapData(256,100,false,0x000000);
//创建模糊滤镜
var blurFilter:BlurFilter = new BlurFilter(2,1.6);

var matrix:Array = new Array();
matrix = matrix.concat([1,0]);// 红
matrix = matrix.concat([0,1,0]);// 绿
matrix = matrix.concat([0,0]);// 蓝
matrix = matrix.concat([0,.85,0]);// 透明度
var alphaFilter:ColorMatrixFilter = new ColorMatrixFilter(matrix);
var bmp:Bitmap = new Bitmap(bmpData);
bmp.blendMode = BlendMode.LIGHTEN;
addChild(bmp);
addEventListener(Event.ENTER_FRAME,enterFrameHandler);

const PLOT_HEIGHT:int = 50;
const CHANNEL_LENGTH:int = 256;
var snd:Sound = new Sound();
var req:URLRequest = new URLRequest("song.mp3");
snd.load(req);
var channel:SoundChannel;
channel = snd.play();
addEventListener(Event.ENTER_FRAME,enterFrameHandler);
snd.addEventListener(Event.SOUND_COMPLETE,onPlaybackComplete);
var bytes:ByteArray = new ByteArray();

function enterFrameHandler(e:Event) {
	SoundMixer.computeSpectrum(bytes,0);
	var n:Number = 0;

	bmpData.applyFilter(bmpData,bmpData.rect,new Point(0,0),alphaFilter);
	bmpData.draw(this);
	
	for (var i:int = 0; i < CHANNEL_LENGTH; i++) {
		n = (bytes.readFloat() * PLOT_HEIGHT);
		bmpData.setPixel((i * 2),(PLOT_HEIGHT - n),0xffCC00);
	}
	
	for (i = CHANNEL_LENGTH; i > 0; i--) {
		n = (bytes.readFloat() * PLOT_HEIGHT);
		bmpData.setPixel((i * 2),0xccff00);
	}
	bmp.bitmapData.copyPixels(bmpData,0));
	bmp.visible = true;
	bmpData.applyFilter(bmpData,blurFilter);
}
//播放结束时删除enterFrameHandler方法
function onPlaybackComplete(event:Event) {
	removeEventListener(Event.ENTER_FRAME,enterFrameHandler);
}