Detecting Display Settings: Use the screenResolutionX and screenResolutionY properties of the system.capabilities object.

package{
import flash.display.Sprite;
import flash.system.Capabilities;
public class Main extends Sprite{
public function Main(){
trace(flash.system.Capabilities.screenResolutionX);
trace(flash.system.Capabilities.screenResolutionY);
}
}
}

प्रेम watch out, this might be userful to us in detecting the video resolution & laying out accordingly.

more useful samples like this can be found here - http://www.java2s.com/Code/Flash-Flex-ActionScript/CatalogFlash-Flex-ActionScript.htm