как сделать регулярку на код ютуба

[sarkis]

всем привет ...В поле должна быть проверка на наличие youtu.be в https:// youtu.be /s9vYn7YnXcY. Т.е в поле добавляют видео и оно заносится в базу..
Как реализовать ?

 

[invader]

function replaceyoutube($text)
{
    $text = preg_replace('~
        # Match non-linked youtube URL in the wild
        https?://         # Required scheme. Either http or https.
        (?:[0-9A-Z-]+\.)? # Optional subdomain.
        (?:               # Group host alternatives.
        youtu\.be/      # Either youtu.be,
        | youtube\.com    # or youtube.com followed by
        \S*             # Allow anything up to VIDEO_ID,
        [^\w\-\s]       # but char before ID is non-ID char.
        )                 # End host alternatives.
        ([\w\-]{11})      # $1: VIDEO_ID is exactly 11 chars.
        (?=[^\w\-]|$)     # Assert next char is non-ID or EOS.
        (?!               # Assert URL is not pre-linked.
        [?=&+%\w]*      # Allow URL (query) remainder.
        (?:             # Group pre-linked alternatives.
        [\'"][^<>]*>  # Either inside a start tag,
        | </a>          # or inside <a> element text contents.
            )               # End recognized pre-linked alts.
            )                 # End negative lookahead assertion.
            [?=&+%\w-]*        # Consume any URL (query) remainder.
            ~ix',
        'http://www.youtube.com/embed/$1',
        $text);
    return $text;
}