OpenShot is a free and open-source video editor. The design isn’t anything fancy compared to paid apps like Final Cut or Premiere but it’s surprisingly powerful and gets the job done.
From its Features page:
Based on the powerful FFmpeg library, OpenShot can read and write most video and image formats. For a full list of supported formats, see the FFmpeg project. OpenShot’s export dialog defaults to some of the more common formats, but with the advanced tab, you can use any FFmpeg format.