I think they were fighting. A surprise feature by konami. :p
Anyway, just follow this format 'http://www.youtube.com/watch?v=1nvhFH0qfOE' as explained above and you should be good to go. Anything after the 12 characters can be removed and usually begins with '&' like in you're link '&feature=youtu.be'. So you can remove everything starting from '&'.
Hey mate, well you've done good removing 's' from http, but sometimes the link is longer than usual. For example, this is what you linked 'http://www.youtube.com/watch?v=1nvhFH0qfOE&feature=youtu.be', and this is how the complete link should look like: 'http://www.youtube.com/watch?v=1nvhFH0qfOE'.
See a difference? It's simple when you get used to it. It just starts with a http (no s), then the typical 'www.youtube.com', then 'watch?' and a 'v=' (for video) and a string of 12 random characters, in your link's case is '1nvhFH0qfOE'. The 'v=1nvhFH0qfOE' is the actual unique video link. These characters are obviously different and unique for each youtube video. You can swap this with any other 'http://www.youtube.com/watch?v=xxxxxxxxxxxx' and you'll get you're video. Maybe you've seen some people on other sites or forums only posting 'v=1nvhFH0qfOE'. You don't have to care about this part though. Just thought I'd let you know
Hope this helps and did not cause more confusion
