^.+(?|&)v=([a-zA-Z0-9]+).*$
hxxp://www.youtube.com/v/$1
hxxp://www.youtube.com/?watch="YoutubeID"
Youtube.com/v/youtubeID.
http://www.youtube.com/watch?v=67-YcLickUA
use strict;
use warnings;
my $string = 'http://www.youtube.com/watch?v=67-YcLickUA';
$string =~ s(.+watch?v=([0-9a-zA-Z-]+))(Youtube.com/v/$1);
print "$stringn";