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);
				}
			}
		}
	}
}