I reverse engineered Apple's video wallpapers

Summary

A video wallpaper engine for macOS Tahoe. Phosphene is a menu bar app + wallpaper extension that plays your own video files as the macOS desktop and lock-screen wallpaper. It plugs into the system's native wallpaper picker, so videos appear alongside Apple's built-in Aerials in System Settings → Wallpaper. It is built on top of Apple's private WallpaperExtensionKit framework — the same one Apple's own Aerials use — which means playback runs out-of-process, survives app quits, and integrates with the OS-level lock-screen / idle / sleep lifecycle. ⚠️ Private framework. Phosphene loads WallpaperExtensionKit via dlopen and uses Mirror-based runtime introspection to talk to its XPC types. Apple could change this at any major OS release. The project tracks macOS 26 (Tahoe). Bring your own videos. Import MP4 / MOV / any AVFoundation-readable file. They show up in the system wallpaper picker. Gapless looping. Frame-accurate loops by offsetting PTS/DTS across loop boundaries — no flush, no stutter. Multi-display + per-Space selections. Different wallpapers per display, persisted by macOS. Power-aware playback. A graduated PlaybackPolicy reduces work or pauses entirely based on thermal state, battery level, on-battery vs AC, Game Mode, and presentation mode (active / locked / idle). Smooth lock-screen ramp. When Only on Lock Screen is enabled, the wallpaper eases in/out with a cubic curve as you lock and unlock, matching Apple's own Aerials behavior. Pause when occluded. Detects when every display is fully covered by windows and pauses rendering until the desktop is visible again. Adaptive variants. Optionally pre-render lower-resolution / lower-fps variants of a video; the renderer swaps to the cheapest variant that satisfies the current policy at each loop boundary. Menu bar control. Preview the current wallpaper, toggle pause, switch displays, configure behavior, launch at login. macOS Tahoe (26.0+). Phosphene depends on the Wallpaper extension point introduced in macOS 14...