RichMedia+

package {
 import flash.display.Sprite;
 import flash.text.TextField;
 
 public class TextFieldSize extends Sprite {
  public function TextFieldSize() {
   var txt:TextField = new TextField();
   txt.text = "0";
   txt.autoSize = "left";
 
   var sp:Sprite = new Sprite();
   sp.addChild(txt);
 
   trace(txt.width, txt.textWidth); // 64 60
 
   sp.scaleX = 2;
   trace(txt.width, txt.textWidth); // 34 30
 
   sp.scaleX = 3;
   trace(txt.width, txt.textWidth); // 24 20
  }
 }
}

package {
 import flash.display.Graphics;
 import flash.display.Sprite;
 import flash.display.StageScaleMode;
 import flash.events.Event;
 import flash.text.TextField;
 
 /**
  * Detect scale of stage with show all mode by TextField.textWidth
  * @author Ticore Shih - http://ticore.blogspot.com/
  */
 public class StageScaleDetector extends Sprite {
 
  public var txt:TextField = new TextField();
  public var stdTextWidth:Number;
 
  public var sp:Sprite = new Sprite();
 
  public function StageScaleDetector() {
   stage.scaleMode = StageScaleMode.SHOW_ALL;
 
   initDetector();
   initBackground();
   initSprite();
 
   addEventListener(Event.ENTER_FRAME, onStageResize);
  }
 
  public function initDetector():void {
   txt.text = "-";
   txt.rotation = 90;
   addChild(txt);
   stdTextWidth = txt.textWidth;
  }
 
  public function initBackground():void {
   var g:Graphics = this.graphics;
   g.lineStyle(10, 0x808080);
   g.drawRect(0, 0, stage.stageWidth, stage.stageHeight);
  }
 
  public function initSprite():void {
   var g:Graphics = sp.graphics;
   g.lineStyle(3, 0);
   g.beginFill(0, 0.5);
   g.drawRect(0, 0, 100, 100);
   g.endFill();
   addChild(sp);
  }
 
  public function onStageResize(e:Event):void {
   var stageScale:Number = stdTextWidth / txt.textWidth;
   sp.scaleX = sp.scaleY = 1 / stageScale;
   sp.x = (stage.stageWidth - sp.width) / 2;
   sp.y = (stage.stageHeight - sp.height) / 2;
  }
 }
}

import flash.events.Event;
import flash.media.Video;
 
stage.addEventListener(Event.ADDED_TO_STAGE,
 function(e:Event):void{
  if (e.target is Video) e.target.smoothing = true;
 }, true);

package {
 import flash.events.ProgressEvent;
 import mx.preloaders.SparkDownloadProgressBar;
 
 public class MySparkDownloadProgressBar extends SparkDownloadProgressBar {
 
  override protected function showDisplayForDownloading(elapsedTime:int, event:ProgressEvent):Boolean {
   /*/
   trace("showDisplayForDownloading: elapsedTime = " + elapsedTime);
   trace("showDisplayForDownloading:" + event.bytesLoaded + " " +
    event.bytesTotal + " " + (event.bytesLoaded < event.bytesTotal / 2));
   //*/
 
   return elapsedTime > 100;
   // return elapsedTime > 700 && event.bytesLoaded < event.bytesTotal / 2;
  }
 }
}

<?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"
  preloader="MySparkDownloadProgressBar">
 
 <s:layout>
  <s:VerticalLayout verticalAlign="middle" horizontalAlign="center"/>
 </s:layout>
 
 <s:Button label="Button" />
 
</s:Application>

package {
 import mx.preloaders.DownloadProgressBar;
 
 public class MyDownloadProgressBar extends DownloadProgressBar {
 
  override protected function showDisplayForInit(elapsedTime:int, count:int):Boolean {
   return elapsedTime > 300 && count == 2;
  }
 
 }
}