RemoveChild() but audio still plays

Question

Hy!
I have a flash website where different pages are movieclips which are added or removed from the main stage, depending on which buttons are clicked.
The problem is that I have a 'video' page where a YouTube player is embedded. The video plays as soon as the movieclip loads, but when I remove the child from the stage and I add another movieclip on top of it, the audio still plays.
I have tried using the SounMixer.stopAll() but it works only when I test swf in Flash. When I open the swf separately from the folder it is in, it doesn't work anymore.
Can somebody please help me?
Thanks a lot!

Answer 1

It is not a FLVPlayback control, it is a YouTube ActionScript 3.0 Player API.
Here is the code :
// The player SWF file on www.youtube.com needs to communicate with your host
// SWF file. Your code must call Security.allowDomain() to allow this
// communication.
Security.allowDomain("www.youtube.com");
// This will hold the API player instance once it is initialized.
var player:Object;
var loader:Loader = new Loader();
loader.contentLoaderInfo.addEventListener(Event.INIT, onLoaderInit);
loader.load(new URLRequest("http://www.youtube.com/apiplayer?version=3")); //load the embedded player
play_btn.addEventListener(MouseEvent.CLICK, playVid);
pause_btn.addEventListener(MouseEvent.CLICK, pauseVid);
video1_btn.addEventListener(MouseEvent.CLICK,playVid1);
video2_btn.addEventListener(MouseEvent.CLICK,playVid2);
video3_btn.addEventListener(MouseEvent.CLICK,playVid3);
mute_btn.addEventListener(MouseEvent.CLICK,muteVideo);
unmute_btn.addEventListener(MouseEvent.CLICK,unmuteVideo);
function onLoaderInit(event:Event):void {
    addChild(loader);
    loader.content.addEventListener("onReady", onPlayerReady);
    loader.content.addEventListener("onError", onPlayerError);
    loader.content.addEventListener("onStateChange", onPlayerStateChange);
    loader.content.addEventListener("onPlaybackQualityChange", onVideoPlaybackQualityChange);
function onPlayerReady(event:Event):void {
    // Event.data contains the event parameter, which is the Player API ID
  trace("player ready:", Object(event).data);
  player = loader.content;
          player.loadVideoByUrl("http://www.youtube.com/v/v6oJ5rw9mys",0);
    // Set appropriate player dimensions an its position
  player.setSize(480, 360);
          player.x=50;
          player.y=220;
          video_title.text="Multiplying Sevens-Times Table";
function onPlayerError(event:Event):void {
    // Event.data contains the event parameter, which is the error code
    trace("player error:", Object(event).data);
function onPlayerStateChange(event:Event):void {
    // Event.data contains the event parameter, which is the new player state
    trace("player state:", Object(event).data);
function onVideoPlaybackQualityChange(event:Event):void {
    // Event.data contains the event parameter, which is the new video quality
    trace("video quality:", Object(event).data);
I have taken this code from its YouTube ActionScript 3.0 Player API Reference