I am using ffmpeg in my java project with javacpp-presets. I want to be able to edit the ffmpeg and libx264 for my needs. I edited the ffmpeg and libx264 source codes, compiled it and use it successfully through the command line. now I want to use the new source code within my java code using the javacpp-preset. how do I configure the javacpp-preset to work with my version of ffmpeg?