[ifrins]

Not the dev, but it seems like this app is using Android's internal audio Visualizer APIs and they require record audio permission even if just visualizing the audio played by the app. https://developer.android.com/reference/android/media/audiof...

[StavrosK]

Huh, that's weird (and broken), thanks for the clarification.

[harjot-oberai]

To get FFT data , the device records a small portion of currently playing audio, analyses it, does some magic signals and systems stuff, and generates an array containing the FFT data. Thus the permission to Record Audio.