Using --enable-libvmaf turns FFmpeg compilation to non-free

I have successfully compiled using instructions at this link with some modifications to libvmaf code section:

wget & -Dbuilt_in_models=false

to point to the latest vmaf code, without inbuilt models & finally adding:

--enable-libvmaf

to the existing lists of configure oprions ...but to my surprise the final build ffmpeg is not non-free ...I mean --libfdk-aac is disabled ...when I run ffmpeg -buildconf on the latest build??

1. It seems to me --enable-libvmaf forces compilation to gpl instead of non-free as using configure without it results in build with --libfdk-aac enabled.
2. How can I build ffmpeg and use both vmaf & fdk-aac?....if it's not possible then how can i keep both statics (non-free & gpl) on ubuntu 20.04 (probably at usr/bin/local) and run as per requirement?

1 Answer

Silly mistake..there was another copy of ffmpeg at /usr/local/bin......& I was using ffmpeg -buildconf instead of ./ffmpeg -buildconf inside a folder.