Download youtube video’s with PHP

<?
//example string for the function
get_youtube_download_link("http://www.youtube.com/watch?v=8yOa-7fHNwo&feature=rec-HM-r2");

function str_between($string, $start, $end){ $string = " ".$string;
$ini = strpos($string,$start); if ($ini == 0) return ""; $ini +=
strlen($start); $len = strpos($string,$end,$ini) - $ini; return
substr($string,$ini,$len); }
function get_youtube_download_link($url){
if( $url !== "")
{
$youtube_link = $url;
//$url = get_post_meta($post->ID, 'url', true);
if ( file_get_contents($youtube_link) !== "")
{
$youtube_page = file_get_contents($youtube_link);
$v_id = str_between($youtube_page, "&video_id=", "&");
$t_id = str_between($youtube_page, "&t=", "&");
$flv_link = "http://www.youtube.com/get_video?video_id=$v_id&t=$t_id";
$hq_flv_link = "http://www.youtube.com/get_video?video_id=$v_id&t=$t_id&fmt=6";
$mp4_link = "http://www.youtube.com/get_video?video_id=$v_id&t=$t_id&fmt=18";
$threegp_link = "http://www.youtube.com/get_video?video_id=$v_id&t=$t_id&fmt=17";
echo "\t\tDownload (right-click &gt; save as)&#58;\n\t\t";
echo "<a href=\"$flv_link\">FLV</a>\n\t\t";
echo "<a href=\"$hq_flv_link\">HQ FLV (if available)</a>\n\t\t";
echo "<a href=\"$mp4_link\">MP4</a>\n\t\t";
echo "<a href=\"$threegp_link\">3GP</a><br><br>\n";
}
}
}
?>