Mac OS High Sierra has changed how the media buttons on the keyboard work. Instead of controlling Itunes, Spotify, VLC and a few other media playback programs, they control anything that's open at the moment. For example, if you listen to Spotify and have a video open here on MacWorld in the browser, pressing the play / pause button will stop the video while Spotify continues.
If you are one of the many users who like it This behavior is purely idiotic, and the media buttons should control the background music playback and not something you like to click on or press space to pause, we have a good news. There is a solution that restores normal behavior.
The developer Milan Toth has developed a small program called High Sierra Media Key Enabler, which makes the media buttons only control Itunes or Spotify and nothing else. It is therefore practical also for those who disturbed how the media buttons could control VLC instead of Itunes or Spotify if it was the latest open media program.
The only cross is that the program only works with physical buttons and not with those Virtual Buttons on Macbook Pro with Touch Bar.
High Sierra Media Key Enabler can be downloaded from the developer's website or from Github where it is open source. Since it has not been signed with a Developer Certificate, you must right-click on the program, choose Open, and then accept that it is running to bypass Gatekeeper. If you do not trust the developer, you can get Xcode and compile the Github code on your own.