Honey, I Shrunk The Vids is a set-and-forget batch video converter powered by FFMPEG. Portable binaries are available for Windows, Linux, and Mac OS (both Intel and Apple Silicon platforms) - your choice of GUI for desktop, or CLI for server use.
AI disclosure, please click for more information: 
Screenshots
Originally I designed it as a PowerShell application with a WinForms GUI (first post for the curious ) because I got tired of tweaking FFMPEG commands per-file, but then wondered if I could port it to a more universal solution. Turned out I could; from the feedback on the second post I've since done several efficiency passes and resolved a number of scaling issues. Full details on the Releases page.
The reason for the version bump to 2.0 is pretty exciting: I added a CLI binary by user request. To support this, I also refactored the engine to decouple it from the frontend so the CLI and GUI use the same backend (purely for maintainability). Fixed remote-mount detection and local staging of remote files (don't wanna slam a CIFS connection with a live transcode, hey!); more efficiency passes, made the log a bit easier to read and added a job progress window, some Mac fixes for Apple's proprietary Spatial Audio tracks returning an unknown codec on probe, and I think it's in a good state at 2.1.1 so I rolled the changes into main with this release. The old GUI-only codebase is retired and this is the base I'll be applying any further updates/bug fixes to.
I took the screenshots as I've been writing this post; I'm actively using this thing on my own machines and so are some of my friends who've been helping me with testing. I hope some of you also find it useful! And of course if you find a bug, have a feature request, or just have questions, please let me know! Bugs, I will fix; feature requests I will at least consider, and may well implement. Questions, I will be happy to answer 😊