Media Player has no Sound

I am playing a video with the media player in the User Interface and the video plays but there is no sound, despite the original video file having sound. Is there something I have to do besides referencing the media player in the graph?

I have the Open Source node and the media player referenced as a variable but apparently that is not enough. However, I am not sure how to play sound if there is a built-in reason that the media player alone doesn’t do that.

You need to add a media sound source, it’s a little counterintuitive but this documentation should explain it pretty simply.