Hi guys,

i am looking for a way to add black bars to a video.
These bars should really hide something that is visible , so a crop will not do the job.

Any ideas how to get this done using kdenlive ?

Here's one out of multiple ways: create a title clip that contains the black bars you want and where you want them to be. The title editor allows you to draw rectangles and to fill them with any color you want. Place the title clip on a track above the track with your clip. Add an affine or composite transition to the title clip. Done.

I don't understand why the clip effect won't work, but since you didn't give any details, I should not speculate. Do you need the black bars in positions other than at the periphery?