The app has in-app music which can be switched off by the user, e.g. if he rather listens to his own music. In the near future, tutorial-videos will be added to the app. These videos don't have and need any sound themselves. The problem is that apple only allows one audio- and videostream at a time - but how about independent audio- and videostreams? It'd be perfect if it were possible to just play the in-game music without interruption while the user watches, pauses or ends the video, as if it were independent, or if he could listen to his own music without having silence while the video is playing or any kind of interruption. The second option - to implement music into the video so it isn't silent - would be the last option, because it would mean that user-music or in-app music - whichever the user prefers - would have to stop playing to play music the user decided not to listen to or at another position on the same or a similar track.