Related question: is there any decent OS software that can intelligently pick encoding parameters that preserve quality while minimizing size?

I recently tried to implement video uploading for an open source project, but naively choosing ffmpeg parameters can often result in noticeable quality loss / large output file size / long encoding time. And easily all three of those at the same time.

I have been interested in this and to my surprise I was able to find just a single project that does something similar: https://github.com/master-of-zen/Av1an

It has the ability to do trial compression (w/ scene splitting) and evaluate quality loss up to a desired factor.