checking mp3 file

I wanted to write php script so that it can upload mp3 file.
but is there a way that i can check that it really is an mp3 but not some text file being renamed to .mp3 extension?

I've looked through some example and found this

    function _checkSongFormat($sSongPath)
    {
		$sSongPath = str_replace(" ","%20",$sSongPath);
        $aMp3Headers = array
        (
            array(0x49, 0x44, 0x33, 0x03),
            array(0xFF, 0xFB),
        );
        $aSongData = array();
        $hF = fopen($sSongPath, 'r');
        for ($i = 0; $i < 4; $i++)
        {
            $aSongData[$i] = bin2hex(fread($hF, 1));
        }
        fclose($hF);
        foreach ($aMp3Headers as $aHeader)
        {
            $bEqual = true;
            for ($i = 0; $i < 4; $i++)
            {
                if (!isset($aHeader[$i]))
                {
                    break;
                }
                if (dechex($aHeader[$i]) != $aSongData[$i])
                {
                    $bEqual = false;
                    break;
                }
            }
            if ($bEqual)
            {
                return true;
            }
        }
        return false;
    }

Code (markup):

But here's the problem...even a real mp3 file sometimes return as false.

 

Check for more info: http://www.hydrogenaudio.org/forums/lofiversion/index.php/t22245.html

 

i dun get it ...wat do u mean by check an mp3 file?

 

I usually just use this on my audio site:

if ($_FILES['audio']['type'] == "audio/mpeg") {
// Continue
} else {
// Error
}

Code (markup):

With the input box name as audio.