This app is is a music visualizer, but it also has a feature to play a silent audio file in the background. This allows it to use the audio tunneling feature that some phones have, so other music played on the device will work with music visualizers.
This app runs a persistent service with a silent audio player that attempts to occupy the audio tunneling feature, so media players won't attempt to use it. The service itself uses very little battery: it simply starts playing a blank audio file and pauses it.
Many thanks to h6a_h4i for finding a workaround for the audio tunneling problem. Check out h6a_h4i's app, Music Visualizer!
