One of the things the Linux desktop sorely needs is a good video editor. I’ve heard of kdenlive before but never tried it. How is it (both for experienced users doing complex editing and for newbies just wanting to trim some footage)? I’ve also seen that black magic’s editor is available for Linux, but it is an enormous package...
I don't know on Linux, but for Windows I also had to search around and manually install some codecs because otherwise it wouldn't render to a given format (I believe it was mp4).
Then I've found OpenShot, that was enough for my requirements (https://www.openshot.org/). It has a Linux version. Source code here: https://github.com/OpenShot/openshot-qt