FLASH26: Applying audio descriptions to Flash video

Example Code:

package {
  import fl.video. *;
  import flash.events. *;
  import flash.media.Sound;
  import flash.media.SoundChannel;
  import flash.net.URLRequest;
  import flash.display.Sprite;
  
  public class AudioDescriptions extends Sprite {
    private var channel: SoundChannel = new SoundChannel;
    private var myPlayer: FLVPlayback;
    private var _enabled: Boolean = true;
    private var _toggleBtn: Button;
    private var snd: Sound = new Sound();
    public function AudioDescriptions() {
      // point myPlayer to the FLVPlayback component instance on the stage, 
      // which should be loaded with a valid video source.
      myPlayer = my_FLVPlybk;
      // add cue points. When any of these are reached, the 
      // MetadataEvent.CUE_POINT event will fire
      myPlayer.addASCuePoint(8.35, "ASpt1");
      myPlayer.addASCuePoint(23.23, "ASpt2");
      
      enable();
      
      enable_AD_btn.addEventListener(MouseEvent.CLICK, handleBtnClick);
    }
    
    private function handleBtnClick(e) {
      _enabled = ! _enabled;
      if (! _enabled) {
        disable();
        enable_AD_btn.label = "Enable Audio Descriptions";
      } else {
        enable();
        enable_AD_btn.label = "Disable Audio Descriptions";
      }
    }
    
    public function enable() {
      // set up an event handler which will be called each time a cue point is reached
      myPlayer.addEventListener(MetadataEvent.CUE_POINT, cp_listener);
    }
    
    public function disable() {
      // remove the event handler called each time a cue point is reached, so 
      // that audio description is disabled.
      myPlayer.removeEventListener(MetadataEvent.CUE_POINT, cp_listener);
    }
    
    private function cp_listener(eventObject: MetadataEvent): void {
      snd = new Sound();
      //recreate sound object as it can only load one mp3 file
      //check to see which cue point was reached
      switch (eventObject.info.name) {
        case "ASpt1":
        snd.load(new URLRequest("sphere.mp3"));
        //create a new Sound object, and load the appropriate mp3
        channel = snd.play();
        // play the audio description, and assign it to the SoundChannel object
        break;
        case "ASpt2":
        snd.load(new URLRequest("transfrm.mp3"));
        channel = snd.play();
        break;
      }
    }
  }
}