<?php
    /* Posted at http://www.w3tools.info/2011/09/php-lame-encoder-mp3-conversion.html */

    function alterBitrate($data,$filefrom,$fileto,$lamepath){
    /*
            $data = array holding data related to mp3.
            $filefrom = Mp3 file path.
            $fileto = Path to save file to
            $lamepath = Path to lame encode
    */
            $tagncmd = array(
                            'br' => '-b',
                            'title' => '--tt',
                            'artist' => '--ta',
                            'album' => '--tl',
                            'comment' => '--tc',
                            'genre' => '--tg',
                            'art' => '--ti',
                            'year' => '--ty',
                            'trackno' => '--tn'
                    );
            $execstr = escapeshellarg($lamepath);
            foreach($data as $k => $v){
                    if($v!="")
                    $execstr .= " ".$tagncmd[$k]." ".escapeshellarg($v);
            }
            $execstr .= " ".escapeshellarg($filefrom)." ".escapeshellarg($fileto);
            echo $execstr;
            echo system($execstr);
    }

    /* USAGE */

    $data = array(
    'br' => 50, // Bitrate
    'title' => 'Something',
    'artist' => 'Someone',
    'album' => 'Somealbum',
    'comment' => 'Altering Bitrate :P',
    'genre' => 'Rock',
    'art' => 'art.gif',
    'year' => '2011',
    'trackno' => '5'
    );

    alterBitrate($data,'F:\php\lame\samp.mp3','F:\php\lame\new.mp3','F:\php\lame\lame.exe');

    ?>