[Plugin: Viper's Video Quicktags] cropped embedded code from youtube dont run

Hi, when i use the cropped embedded code from youtube like this:

https://www.youtube.com/v/zlfKdbWwruY

the plugin dont run.

when i changed the code to

https://www.youtube.com/watch?v=zlfKdbWwruY

then it go.

What is the mistake in the plugin?

I think, we simple cropped and paste the code in and dont we must change the code?!