flash播放音频显示波形

package
{
//引入相关的类
import flash.display.Sprite;
import flash.display.Graphics;
import flash.media.Sound;
import flash.media.SoundChannel;
import flash.media.SoundMixer;
import flash.net.URLRequest;
import flash.events.Event;
import flash.utils.ByteArray;

//自定义wave类，实现相关操作
public class wave extends Sprite
{
//定义所需变量
private var sound:Sound;
private var ba:ByteArray;
private var num:Number;
private var sound_channel:SoundChannel;
private var t:Number=0;

public function wave()
{
sound=new Sound();
ba=new ByteArray();
sound.load(new URLRequest("test.mp3"));
sound_channel=sound.play();
//添加事件侦听，用spectrum函数处理
this.addEventListener(Event.ENTER_FRAME,spectrum);
}
//侦听处理函数，调用绘制波形函数
private function spectrum(event:Event)
{
graphics.clear();
drawFunction(1,0xbb11aa);

}
//绘制波形主函数
private function drawFunction(thickness:Number,color:Number)
{
graphics.lineStyle(thickness,color,100);
//获取当前声音频谱信息
SoundMixer.computeSpectrum(ba,false,0);
//绘制声波曲线
for(var i=30;i<=stage.stageWidth-30;i++)
{
//以浮点形式读出当前声音频谱信息
num=ba.readFloat()*360;
if(i>30)
{
var fi=stage.stageHeight/2+num;
graphics.lineTo(i,fi);
}
else
{
trace(i);
graphics.moveTo(30,stage.stageHeight/2+num);
}
}
}
}
}