When writing my filtergraphs, I’ve found the following three “tricks” to be immensely helpful
Use an actual editor. Fish shell has a keybind that opens the current prompt in your $EDITOR, and saving+quitting returns to the editor. Makes multi line ffmpeg filters trivial. Doubly so if your editor has something like TabNine completions
If that’s not enough, write the filter in a dedicated file, and use either editor automation or something like entr to run ffmpeg’s graph2dot command and then graphviz to get a visualization of said graph. Helps ferret out bugs
Build up more complex graphs using either ffplay or mpv. You can add filters at runtime to mpv via the repl (press ~) and the vf add command
But part of the fun of FFmpeg is spending two days trying to figure out how to get it to do what you are trying to do.
When writing my filtergraphs, I’ve found the following three “tricks” to be immensely helpful
$EDITOR, and saving+quitting returns to the editor. Makes multi line ffmpeg filters trivial. Doubly so if your editor has something like TabNine completionsvf addcommand