ffmpeg has a lot of dependencies.
Can you choose which codecs you want to compile in or not ?
E.g.
ffmeg.config = “I want these codecs”
or a curses window which allow to choose ?
Cfr. gentoo “use flags” or freebsd “make config”.
You can choose to install these manually, if you need those features. All other dependencies are not optional and will be automatically installed when you install ffmpeg.
Since ffmpeg is in the repos, you do not compile it when you install it, your package manager (pacman) downloads a binary package which was built by the Arch devs.
EDIT: since the question of this topic has been edited by the OP, this answer is no longer applicable. At first it was a question about the ffmpeg in the repos, now it is about ffmpeg-git, from the AUR. I’m out of here, before I waste any more time answering a question which may be sneakily changed again.
If you pass the --editmenu option to yay it will give you the ability to edit the PKGBUILD inline
Alternatively, you could save into the config and you would always have that option. Personally, I have the diffmenu on all the time and only turn the editmenu on when I need it.