What exactly is FFMPEG an alternative to? I keep hearing people mention it, but I’ve never stopped to look into it until now.

I tend to do some very basic video editing just to put an image with an audio file so I can upload my music to YouTube. This can do what I need it to do? To what degree can this replace a video editor with a full graphical interface?

Edit: Nevermind. I definitely misunderstood what the tool was at a fundamental level. Got it now.