C

concatenate

Cluster-concat is a pipeline that auto-extracts features from video clips, places them on an Endel-style grid, groups them by nearby BPM, and generates ffmpeg concat lists. It also includes X (Twitter) re-encode steps, so you can drop in a bunch of clips and get concatenated videos almost fully automatically.

split one file into many or concatenate them back to one

Concatenate file(s) to standard output or file. https://github.com/ethauvin/dcat

Shake off extra weight from videos

Resize/slice/join video file using ffmpeg(x264) with a Gtk+ GUI.