Strobe help

Hello

I am new to FCPX and have been using it for the past month or so.

In my current project I would like to be able to make the screen strobe/blink/flash at a certain rate per minute - specifically between 8-13 per second over the top of the footage I have, rather than replacing it.

I have tried to achieve this with the 'flashing' effect in the video filters menu but I can't seem to adjust anything other than the 'intensity' which seems pointless.

I have searched for similar questions and answers but can't find an answer for this with FCPX.
I have seen the blink filter discussed but I don't think this is in FCPX?

Any help as to how I can achieve this is much appreciated

You want it to blink to what color?
Very easy to do in Motion.

Check the free fcpx plugins on this forum and look for the AB Source strobe effect posted by NocoDave. There is also a newer version on the app store. It will do what you want.

But as BenB suggests, if you are familiar with Motion you can customize your own effect and publish it directly to FCPX.