"Assembly language of FFmpeg" leads me to think of -filter_complex. It's not for human consumption even once you know many of its gotchas (-ss and keyframes, PT

"Assembly language of FFmpeg" leads me to think of -filter_complex. It's not for human consumption even once you know many of its gotchas (-ss and keyframes, PTS, labeling and using chain outputs, fading, mixing resolutions etc). But then again no-one is adjusting timestamps manually in batch scripts, so a high-level script on top of filter_complex doesn't have much purpose.