Bulk Rename Utility

Suppose I have Files named like:
Title1.mp4,Title2.mp4,Titlex.mp4

And then I have some random files of different extension(lets say .srt)
I want to multiple copy the name of .mp4 to .srt files(May or may not be in the same directory)

How do I do that?

Thank in Advance!

Hi, can you give examples please? thanks

I want to rename All the subtitle files as the name of the mp4 files.http://imgur.com/a/i0HAf