Setting the skin background alpha on an FLVPlayback control skin in Flash using ActionScript 3.0

// ActionScript 3.0
/* Requires
 * - FLVPlayback control in Flash library
 * - Slider control in Flash library
 * - SkinOverPlaySeekMute.swf file in same directory as Flash document
 */
import fl.controls.Slider;
import fl.events.SliderEvent;
import fl.video.FLVPlayback;
 
var slider:Slider = new Slider();
slider.minimum = 0.0;
slider.maximum = 1.0;
slider.value = 0.85;
slider.snapInterval = 0.05;
slider.liveDragging = true;
slider.addEventListener(SliderEvent.CHANGE, slider_change);
slider.move(10, 10);
addChild(slider);
 
var flvPlayback:FLVPlayback = new FLVPlayback();
flvPlayback.autoPlay = false;
flvPlayback.source = "http://www.helpexamples.com/flash/video/cuepoints.flv";
flvPlayback.skin = "SkinOverPlaySeekMute.swf";
flvPlayback.x = 10;
flvPlayback.y = 40;
addChild(flvPlayback);
 
function slider_change(evt:SliderEvent):void {
    flvPlayback.skinBackgroundAlpha = evt.value;
}