Cine Encoder is an application that allow to convert media files while preserving HDR metadata.
Videomassa
It is a FLOSS, powerful, multitasking and cross-platform graphical user interface (GUI) for FFmpeg and yt-dlp.
MystiQ
Easy to use and elegant Multimedia converter.
Frenu à manu
HandBrake is an open-source video transcoder.
Cianu
The ciano is a multimedia converter for all the format you need.