How do i play a song from library when the preloader is a "x"% of total loaded? - actionscript-3

Question

I am currently undertaking a final exam based on the presentation of an offline portfolio and I need to make a preloader, where when the process of loading is 25% of total bytes, to play a sound that is imported into the library. I've tried several ways and can’t do it.
I'll leave you the code for my preloader.
//(also this code is a mouse loader in text form)
this.loaderInfo.addEventListener(ProgressEvent.PROGRESS,checkingProgress);
function checkingProgress(event:ProgressEvent):void{
var procentLoaded:Number = event.bytesLoaded/event.bytesTotal*100;
ptxt.text=int(procentLoaded)+"%";
if(procentLoaded == 100){
this.gotoAndPlay(1,"Video-Int");
}
}
stage.addChild(ptxt);
ptxt.mouseEnabled = false;
ptxt.addEventListener(Event.ENTER_FRAME, fl_CustomMouseCursor);
function fl_CustomMouseCursor(event:Event) {
ptxt.x = stage.mouseX;
ptxt.y = stage.mouseY;
}
Mouse.hide();
this.addEventListener(Event.ENTER_FRAME, loading);
function loading(e:Event):void {
var total:Number = this.stage.loaderInfo.bytesTotal;
var loaded:Number = this.stage.loaderInfo.bytesLoaded;
prel.scaleX = loaded/total;
if (total == loaded){
play();
this.removeEventListener(Event.ENTER_FRAME, loading);
}
}

Answer 1

You need to make the sound file in your library available for actionscript.
Give it a Class name ex. MySound
...
var mysound:MySound = new MySound();
var soundPLaying:Boolean = false;
function checkingProgress(event:ProgressEvent):void{
var procentLoaded:Number = event.bytesLoaded/event.bytesTotal*100;
ptxt.text= procentLoaded +"%";
if(procentLoaded > 25 && !soundPlaying){ //check if loaded mor then 25% and sound isn't playing
mysound.play();
soundPlaying = true;
}
if(procentLoaded == 100){
this.gotoAndPlay(1,"Video-Int");
}
}
...
if you need to do some extra stuff like pause, change volume etc you will need a SoundChannel Object