get_vimeo_id

https?:\/\/                   // Required scheme. Either http or https.
  (?:[a-z0-9-]+\.)?           // Optional subdomain.
  vimeo\.com\/                 // Domain name.
  (?:                         // Group path alternatives.
    moogaloop.swf\?clip_id=   // Either moogaloop.swf?clip_id=
    |video\/                   // or video/
  )?                          // or nothing. End path alternatives.
  (?:
    channels\/                // channels/channel_name/
    [^\/]+\/
  )?
  (?:                         // groups/group_name/videos/
    groups\/
    [^\/]+\/
    videos\/
  )?
  ([0-9]+)                    // $1: Video id is a number.
[?=&+%#!\-\w\.]*            // Consume any URL (query) remainder.

/https?:\/\/(?:[a-z0-9-]+\.)?vimeo\.com\/(?:moogaloop.swf\?clip_id=|video\/)?(?:channels\/[^\/]+\/)?(?:groups\/[^\/]+\/videos\/)?([0-9]+)[?=&+%#!\-\w\.]*/i