Embedded youtube plays video too fast with no sound

Question

I am trying to implement the YT player in a Javascript based app for Samsung smart TV. The problem is that the video I want to use plays without sound and to fast. Is any of you hae an idea why??

Here the code I am using (the video was encoded in .mp4 format http://www.youtube.com/watch?v=l4uSJ-LpkwY):

var player=false; 

function onYouTubePlayerReady(playerId) {
                   player = document.getElementById(playerId);

                   Player.init();
//                 Player.setWindow();
}               

var Player = {};

Player.init = function(){

    this.playVideo("l4uSJ-LpkwY");
    this.setWindow();

}
Player.setWindow = function(){

        document.getElementById('ytplayer').style.width = "450px";
        document.getElementById('ytplayer').style.height = "450px";     
        document.getElementById('ytplayer').setSize(450,450);


}

Player.setFull = function(){

        document.getElementById('ytplayer').style.width = "960px";
        document.getElementById('ytplayer').style.height = "540px";     
        document.getElementById('ytplayer').setSize(960,540);


}

Player.onStateChange = function(state){

}

Player.playVideo = function(url){
    player.loadVideoById(url);
}

Player.stopVideo = function(){
    player.stopVideo();
}

Player.pauseVideo = function(){
    player.pauseVideo();
}

Best regards, Jérémy D.