Shutter Encoder is an open source converter designed by video editors

Shutter encoder app window showing a large image in teh centre ofa pot with some food next to it. Below that can be seen an audio waveform typically seen in video editors. To the righ are numerous settings toggles for video bitrate, audio codecs, video cropping, etc.

Handbrake may well immediately come to mind. This is similar in what it does (conversion based on FFmpeg in the background) but it looks a lot better and easier to use, and has quite a few functions that do not convert video for example: Cut without re-encoding, Replace audio, Rewrap, Conform, Merge, Extract, Subtitling, Video inserts.

It also categorises the video conversions by separating editing formats for output type formats. It is cross-platform for Windows, macOS, and Linux (including AppImage format).

Furthermore, it also has a Watch Folder feature to watch where you may render videos too, and when that render is completed, Shutter Encoder can auto convert e.g. for output say of DaVinci Resolve on Linux, this can do the conversion to H.264.

See https://www.shutterencoder.com