I've never installed the VLC pack, if that's separate from the Player. Most of my other software video related don't see the ffmpeg codec.
ffmpeg is not a codec, it's a software that handles a collection codecs such as libavcodec. Usually just having VLC installed is enough support for other applications, but the VLC pack broadens that support. https://ffmpeg.org/about.html
I usually hold off on plugins until I need them but it's not always easy when you're naturally curious. Plugins are dlls or dynamic link libraries. Dlls' are intended to save space by being available to multiple applications for use which is why a single codec can be linked to by several different applications. If you get a message about a missing dll, more often than not it's easier to locate and download the single dll, and then manually install it.