I am writing a C# SDK (to be used by UWP Publishers) and would like to detect if another application (Pandora, Spotify, Amazon Music, etc.) is playing music in the background, so that I can mute my SDK's sounds.
This comment to this question seems to indicate that I can use BackgroundMediaPlayer.IsMediaPlaying(), but when I play Pandora in a web browser, or the Amazon Music App, this method seems to always return false when music is playing in another app.
This answer to this question seems to indicate that we used to be able to use Microsoft.Xna.Framework.Media.MediaPlayer.State to detect if another app was playing background music, but I don't believe this call is not available in UWP (please let me know if I'm wrong -- I mainly care about this working on Desktop and XBox One).
So my question is, how can I determine if another app (on desktop or in web browser or on Windows phone) is playing music?