PlayerPlugin (Safari Internet plug-in) quit unexpectedly

Dear All, I would be very grateful if you could help me with the following

Since about a month I'm constantly receiving a warning pop up saying that:

PlayerPlugin (Safari Internet plug-in) quit unexpectedly while using the libgsttspplugin.so plug-in.

It occurs every 10'and it is very annoying .. I could not find any solution googling online so I do hope some of you super helping genious will give me the trick I am looking for to finally get rid of it.

Safari Version 11.0.2 (13604.4.7.1.3)

MacBook Pro Mac 13-inch, 2017) running macOS High Sierra version 10.13.2

Many many thanks in advance and a very nice day to you all.

Carolina