Media Tags regex code needed for modified YouTube links in Invision Power Board

Question

IPBoard already comes with relevant regex codes for regular YouTube links. I need help with a different kind of YouTube links that are sent through subscription update emails. Here are some example links:

http://youtube.com/attribution_link?a=r_FgjB-RKNo&u=/watch%3Fv%3DB0_X8zWJd0Q%26feature%3Dem-uploademail (B0_X8zWJd0Q)
http://youtube.com/attribution_link?a=1crTn2Lx38I&u=/watch%3Fv%3DHhebhh2s5d4%26feature%3Dem-uploademail (Hhebhh2s5d4)
http://youtube.com/attribution_link?a=_zMgiznzBto&u=/watch%3Fv%3D-kaoCPvUHJM%26feature%3Dem-uploademail (-kaoCPvUHJM)
http://youtube.com/attribution_link?a=F8VReY1sT0A&u=/watch%3Fv%3D5RLM9rk0Q8s%26feature%3Dem-uploademail (5RLM9rk0Q8s)

The code in the brackets at the end is the relevant YouTube video ID. attribution_link?a= seems to include random digits for different videos.

Here is what IPBoard backend shows:

Existing regex structure for regular YouTube links:

http(?:s)?://(www.)?youtube.com/watch\?(\S+?)?v=([\d\w-_]+?)(&\S+?)?

This converts to:

<iframe id="ytplayer" class="EmbeddedVideo" type="text/html" width="640" height="390" src="http://youtube.com/embed/$3?html5=1&fs=1" frameborder="0" allowfullscreen webkitallowfullscreen /></iframe>

IPBoard Guidelines::

Media Replacement Match

Example Link: http://www.test.com/23423/

Match: http://www.test.com/{1}/

Media Replacement HTML

You can use $1, $2, etc as variable replacements.

Example Link: <a href="http://www.testm.com/$1/">$1</a>

Result: <a href="http://www.testm.com/23423/">23423</a>

Answer 1

Updated expression to handle embedded urlencoded links:

youtube.*?watch.*?v(?:%25|=)([\d\w-_]+)

Example: http://regex101.com/r/fO6qE5

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Old:

http(?:s)?:\/\/(?:www\.)?youtube\.com\/.*?watch%3Fv%([\d\w-_]+)

Example: http://regex101.com/r/cX9rP2