The one button in the installer you are remembering is actually unrelated. It's the gahnome people taking worst from winblows as usual and sticking with it after the last benefits die.

This time it's the video codec system (instead of just using ffmpeg lul), they called it "gstreamer". If you try to install ALL gstreamer plugins, it will be some two digit gibibyte number (don't remember exactly). The button in the installer installs most popular plugins.

Now, applications that try to use it will do anything but tell you what you are missing. Segfault, "whoopsie daisy unknown error", just hang around and so on and so forth. Chances are, it's not in dependencies either, recommended or required. One would think the ffmpeg plugin in the base set can do anything, but as it turns out it can't. For some reason.