Sound duration in AS3

Hi every bodyI need to create a player to stream audio files (mp3 and other audio extentions) in my website. To create this player I used flash cs3 and actionscript3.I found actionscript 2 is easyer to creat and get duration (mysound.duration) but in ac3 I can’t get sound duration with this syntext : "mySound.duration"attention : In ActionScript3 BEFORE loading is completed , I need my audio file in player to show duration and displayed minute and second in the stage.I tried so many solutions in the internet but all of them provide sound duration AFTER loading is Completed (but I need sound duration BEFORE loading is Completed)attention : My audio files are multi bitrate rang exp.(24 kbs , 34kbs , 128kbs or higher).I am trying to get audio DURATION of audio “total bytes” but these solutions just are right for only 128kbs audios.I need any help to solve this problem.please help meThank you