The demo application is the reference for a QuickTime-inspired playback shell.
Patterns shown by the demo
centered floating transport HUD
auto-hide playback controls
title-bar integration on macOS
native macOS menu wiring
backend and renderer preference toggles
workflow entry points for export and recording
Recommendation
Keep your reusable playback control surface in MediaPlayer.Controls, then place app-specific shell behaviors in your own view models and services. The demo shows the composition pattern, but the reusable primitives now live in the control library where possible.