In Flex3,NetStream publishs record ，the video has no image,only has voice

<?xml version="1.0" encoding="utf-8"?>

<mx:Application xmlns:mx="http://www.adobe.com/2006/mxml" layout="absolute" creationComplete="init();">

<mx:Script>

<![CDATA[

import mx.controls.Alert;

import mx.core.mx_internal;

import flash.media.Camera;

private var nc:NetConnection;

private var ns:NetStream;

private var crm:Camera;

private var mic:Microphone;

private var shobj:SharedObject;

private var myurl = "rtmp://localhost:8888/video/flv";

private function init():void{

crm = Camera.getCamera();

mic = Microphone.getMicrophone();

     if(crm){

          crm.setMode(video.width,video.height,200,true);

          crm.setQuality(0,70);

          video.attachCamera(crm);

          conn();

     }else{

          Alert.show("USING");

     }

}

private function conn():void{

            nc = new NetConnection();

            nc.connect(myurl);

            nc.addEventListener(NetStatusEvent.NET_STATUS,onNetStatusHandler);

}

private function onNetStatusHandler(evt:NetStatusEvent):void {

            if(evt.info.code=="NetConnection.Connect.Success")

            {

                shobj = SharedObject.getRemote("show",nc.uri,true);

               shobj.addEventListener(SyncEvent.SYNC,sharedObject_func);

               shobj.connect(nc);

                ns=new NetStream(nc);

                ns.addEventListener(NetStatusEvent.NET_STATUS,onNetStatusHandler);

                ns.attachCamera(crm);

                ns.attachAudio(mic);

                ns.publish("tmp_vedio","record");

            }

        }

]]>

</mx:Script>

<mx:VideoDisplay width="167" height="144" id="video"/>

</mx:Application>

         So,I play the record video , but there is no image , just voice . (My compute's carema is good) Anyone can help me ? Thanks.