function is_utf($str){
    return (iconv("UTF-8","UTF-8",$str)==$str) ? 'utf8' : 'cp1251';
}

function GetFileEncoding($filepath){
    if (file_exists(realpath($filepath))){
        $media = new ffmpeg_movie(realpath($filepath));
        return  is_utf($media->getArtist());
    }
    return false;
}