fast PHP function to check if youtube video is still valid:

<?php
function checkYoutubeId($id) {
if (!$data = @file_get_contents(”http://gdata.youtube.com/feeds/api/videos/”.$id)) return false;
if ($data == “Video not found”) return false;
return true;
}

function checkYoutube($vid) {

if (strlen($vid) < 12) { return checkYoutubeId($vid); }

$preg1 = ‘@www.youtube.com\/watch\?v=(.*?)$@’;
if ( preg_match($preg1, $vid, $match) ) {
$id = explode(”&”,$match[1]);   return checkYoutubeId($id[0]);
}

$preg1 = ‘@www.youtube.com\/v\/(.*?)$@’;
if ( preg_match($preg1, $vid, $match) ) {
$id = explode(”&”,$match[1]);   return checkYoutubeId($id[0]);
}
}
?>

$vid posible format/sintax:

1. http  ://www.youtube.com/watch?v=[ID]&feature=…&…
2. http  ://www.youtube.com/watch?v=[ID]
3. www.youtube.com/watch?v=[ID]
4. youtube.com/watch?v=[ID]
5. http ://www.youtube.com/v/[ID]
6. www.youtube.com/v/[ID]
7. youtube.com/v/[ID]
8. [ID]
9. …. and any valid youtube video url