Here’s sort of how that waveform animation works:
- A Core Animation package [1] creates a particle emitter and overlays a teal/white glow on top of it
- A shader warps the waveform view (not shown) based on time — not volume/amplitude
- Weird shit ensues with how the package is built, how the system renders CA packages, and the demo app allowing the springboard wallpaper to bleed through in the app switcher

[1] https://rambo.codes/posts/2018-11-09-animations-are-assets