use strict;
use warnings;

use Parse::BBCode;
my $p = Parse::BBCode->new({
    tags => {
        youtube => {
            code => sub {
                my ($parser, $attr, $content) = @_;
                my $id = $$content;
                if ($id =~ m{^http://www\.youtube\.(?:de|com)/(?:(?:watch)?\?v=|embed/)(\S*)$}) {
                    $id = $1;
                }
                my $escaped = Parse::BBCode::escape_html($id);
                return qq{<iframe width="400" height="300" }
                    . qq{src="http://www.youtube.com/embed/$escaped" }
                    . qq{frameborder="0" allowfullscreen></iframe>};
            },
            parse => 0,
        },
    },
});
my $bbcode = do { local $/; <DATA> };
my $html = $p->render($bbcode);
print $html;

__DATA__
[youtube][/youtube]
[youtube]1234_Abc[/youtube]
[youtube]http://www.youtube.de/?v=1234_Abc[/youtube]
[youtube]http://www.youtube.de/embed/1234_Abc[/youtube]
[youtube]foo bar bam 123[/youtube]
[youtube]http://www.youtube.com/watch?v=Hg8Fa_EUQqY[/youtube]