Hi,

I have two videos. One is a translation into sign language. Now I want a smaller video with the translation to be within the other video.

I put the sign language video on the upper trace, the other below. I could also cut the sign language video and make it smaller. But now, around this video everything is black. It does not show the second video which is below.

How can I have this black area transparent?

I tried it with bluescreen and composite, but then, everything within the sing language video that is black becomes also transparent.

Thank you very much for help!

Clips normally don't come with any transparency and Kdenlive's tracks in the timeline don't work like layers in graphics programs. What you want is a transition. Yes, that's right. In you case, add an Affine transition to the clip in the upper track. The affine transition allows you to resize and position your clip with respect to the clip on the next track ( or a different track you are compositing with). Take a look at the transition's properties.