я не знаю, почему у вас он двоится, я просто предложил, вариант решения проблемы

Код:
var connection_nc:NetConnection = new NetConnection();
connection_nc.connect(null);
this.createEmptyMovieClip("flv_mc", this.getNextHighestDepth());
var stream_ns:NetStream = new NetStream(connection_nc);
my_video.attachVideo(stream_ns);
flv_mc.attachAudio(stream_ns);
var audio_sound = new Sound(flv_mc);
stream_ns.play("1.flv");
function onEnterFrame(){
trace(stream_ns.time);
}
f1... .

Код:
var my_nc:NetConnection = new NetConnection();
my_nc.connect(null);
var my_ns:NetStream = new NetStream(my_nc);
my_video.attachVideo(my_ns);
my_ns.play("yourVideo.flv");
this.createEmptyMovieClip("flv_mc", this.getNextHighestDepth());
flv_mc.attachAudio(my_ns);
var audio_sound:Sound = new Sound(flv_mc);