Kdenlive

Kdenlive is a free and open-source video editor that brings professional-grade video editing capabilities to everyone. It is built for the whole range between a simple family video and a complex project, and it is community driven rather than the product of a single vendor.

The application is written in C++ and assembled from a handful of open technologies, which is worth knowing before packaging it or sending a patch.

A few names cover both the stack and where the work actually happens.

• MLT: the core framework providing the video editing functionality.
• Qt and KDE Frameworks 6: the GUI layer the interface is built on.
• frei0r: the library behind the video effects.
• LADSPA: the library behind the audio effects.
• KDE Invent: primary development runs on KDE's GitLab instance, and code contributions belong there rather than on the GitHub mirror.

Newcomers are pointed at the build instructions, the architecture and coding guidelines, and an introduction to MLT, plus a developer Matrix channel where the maintainers ask you to get in touch before starting on a task. Open issues on KDE Invent, some of them labeled First Task, and reports in the KDE bug tracker are the suggested places to look.

Stable releases and experimental daily builds are both published on the project website. Contribution is not limited to code either, since translation, bug reporting and triage, documentation, tutorials and helping other users on forums are all listed as ways in.