Classe

Olá pessoal não tenho muita experiencia com php e estou querendo usar um sistema meio que pronto de conversão de video do youtube eu achei esse seguinte sistema:

é um arquivo que se chama "youtubemp3.php" com o seguinte codigo:

<?php

class youtubemp3{

// Cool

	private $videoID;
	private $fileName;
	private $fileTime;
	private $initURL;
	private $fileCC;
	public $fileInfo;

	// Create cURL init url with constructor
	public function __construct($videoID){
 $this->videoID = $videoID;
 $this->fileTime = time();
 $this->fileCC = $this->videoID.$this->fileTime;
 $this->initURL = "http://www.youtube-mp3.org/get?ab=128&video_id={$this->videoID}&r={$this->fileTime}.{$this->cc($this->fileCC)}";
	}

	// Create "r" parameter part for init url
	private function cc($a){
 $m = 65521;
 $b = 1;
 $c = 0;
 $d = "";
 for($i=0; $i<strlen($a); $i++){
 $d = ord($a[$i]);
 $b = ($b+$d)%$m;
 $c = ($c+$b)%$m;
 }
 return $c<<16|$b;
	}

	// In fact, this is a fake conversion function.
	public function convert(){
 $ch = curl_init();
 curl_setopt ($ch, CURLOPT_URL, $this->initURL);
 curl_setopt ($ch, CURLOPT_COOKIEFILE, 'cookie.txt');
 curl_setopt ($ch, CURLOPT_COOKIEJAR, 'cookie.jar');
 curl_setopt ($ch, CURLOPT_REFERER, "http://www.youtube-mp3.org/");
 curl_setopt ($ch, CURLOPT_USERAGENT, "Mozilla/5.0 (compatible; MSIE 5.01; Windows NT 5.0)");
 curl_setopt ($ch, CURLOPT_RETURNTRANSFER, 1);
 curl_setopt ($ch, CURLOPT_HEADER, 1);
 $content = curl_exec ($ch);
 curl_close ($ch);
 $pm = preg_match("/Location: (.*?)/iU", $content, $matches);
 $r = rtrim($matches[1]);
 $result = isset($r) ? array("status" => true, "url" => $r) : array("status" => false);
 if($result["status"]){
 $headers = get_headers($result["url"],1);
 $fn = explode("?", basename($result["url"]));
 $this->fileName = $fn[0];
 $this->fileInfo = array(
 "id" => $this->videoID,
 "name" => $this->fileName,
 "size" => $headers["Content-Length"],
 "url" => $result["url"],
 "headers" => array(
 "Content-Type: {$headers["Content-Type"]}",
 "Content-Length: {$headers["Content-Length"]}",
 "Content-Transfer-Encoding: Binary",
 "Content-disposition: attachment; filename={$this->fileName}"
 )
 );
 }else{
 $this->fileInfo = false;
 }
 return $this;
	}

	// Create header & read file
	public function download(){
 if($this->fileInfo){
 foreach($this->fileInfo["headers"] as $headerString){
 header($headerString);
 }
 readfile($this->fileInfo["url"]);
 }
	}
}

/*
* EXAMPLE
* EXAMPLE URL :

* EXAMPLE URL ID : ydRAb9cwHnA
*/

$MP3 = new youtubemp3("ydRAb9cwHnA");
$MYFILE = $MP3->convert();

/*
* Optional data ( Never use with download function! )

 * print_r($MYFILE->fileInfo);
 */
$MYFILE->download();

/*
* tadaaa! Your MP3 file downloaded...
*
* You can use this way

 * $MP3->convert()->download();
 * because this class have a fluent interface.
 */
?>Dai preciso criar o formulario para enviar a url o "youtubemp3.php"

No tutorial desse sistema o cara da as seguintes dicas para usar:

$MP3 = new youtubemp3("ydRAb9cwHnA");
$MYFILE = $MP3->convert();

Optional data ( Nunca use com função de download! )

print_r($MYFILE->fileInfo);

$MYFILE->download();

tadaaa! Seu arquivo MP3 baixado ...

Você pode usar esse caminho
$MP3->convert()->download();
porque esta classe tem uma interface fluente.

Alguem me ajudaa