[The Geek]

You only use the Embedding Regexp if the data needed to embed cannot be found within the URL itself.

For example:

if the embed code for www.myvideo.com/watch.php?v=123456 looks like:
<embed src="http://www.myvideo.com/watch.php?v=abcdef" ... />

In this instance, the URL doesnt 'tie up' to the embed HTML so AME needs to go to www.myvideo.com/watch.php?v=123456 and find the abcdef part. With the Embedding Regexp, AME pulls down the page and runs something like:

http://www\.myvideo\.com/watch\.php\?v=(\w+)

Which grabs the abcdef part so the video will properly embed.

In the event that the URL contains the information you need (i.e. the dailymotion definition I just posted) then this process is redundant and a time waster. Furthermore, the Embedding Regexp is generally different than the regexp used to match the URL in the first place.

Hope this helps.