在网上找了很多都是flex3的，发现错的也没用

 代码如下：

<?xml version="1.0" encoding="utf-8"?>
<s:Application xmlns:fx="http://ns.adobe.com/mxml/2009" 
			   xmlns:s="library://ns.adobe.com/flex/spark" 
			   xmlns:mx="library://ns.adobe.com/flex/mx" minWidth="955" minHeight="600" xmlns:custom="custom.*">
	<fx:Declarations>
		<!-- 将非可视元素（例如服务、值对象）放在此处 -->
	</fx:Declarations>
	<fx:Script>
		<![CDATA[
			import mx.events.FlexEvent;
			
			import org.osmf.events.MediaPlayerStateChangeEvent;
			private function checkState(e:MediaPlayerStateChangeEvent):void{
				if(e.state == "playing") 
					vid_player.videoObject.smoothing = true;
			}
			
		]]>
	</fx:Script>
	
	
	<s:VideoDisplay id="vid_player" top="0" left="0" right="0" bottom="0" scaleMode="stretch" source="http://helpexamples.com/flash/video/clouds.flv"  mediaPlayerStateChange="checkState(event)" />
</s:Application>

Flex4 VideoDisplay smooth 在全屏状态下消除锯齿