How can convert the below youtube urls 

```
$url1 = http://www.youtube.com/watch?v=136pEZcb1Y0&feature=fvhl
$url2 = http://www.youtube.com/watch?feature=fvhl&v=136pEZcb1Y0

```

into 

```
 $url_embedded = http://www.youtube.com/v/136pEZcb1Y0

```

using Regular Expressions?