FFMPEG with NDI support

Unfortunately, FFMPEG does not support NDI due to copyright issues but wait there is a recent Github tutorial that brings back NDI support on Linux machines.

For MacOS several patches/versions are outdated while I now found that the old method posted by Johan Els on Github several years ago still works.

As I can stream now basically every camera under macOS and Ubuntu using gphoto2 and ffmpeg, I am ready to sell my whole HDMI setup including the Atem Mini – at least at sometime in the near future ;-)