kageroumado/phosphene

Phosphene is a macOS app that lets you use your own video files as the desktop wallpaper and lock screen background on Apple's latest version of macOS, called Tahoe. It is a menu bar app paired with a wallpaper extension. Once installed, you add MP4 or MOV files through the menu bar, then pick them from the standard System Settings panel where you would normally choose between Apple's own moving wallpapers like the Aerials. The way it talks to the system is not entirely supported. The README is honest that the project loads a private Apple framework called WallpaperExtensionKit using a low-level dlopen call, and inspects internal types using Swift Mirror reflection because the real definitions are not published. The author warns that Apple could change those internal types in a future macOS release and break the app. The project currently targets macOS 26 Tahoe on Apple Silicon Macs, and needs Xcode 17 with Swift 6 to build. A fair amount of engineering went into making the video look natural as a wallpaper. Loops are designed to be gapless by adjusting timestamps across the loop boundary so there is no visible stutter. A PlaybackPolicy module slows down or pauses the video based on thermal state, battery level, whether the Mac is on AC power, Game Mode, or whether the screen is locked or idle. Multiple displays each get their own selection, and rendering pauses when every desktop is fully covered by windows. There is also an adaptive variants system that pre-renders lower resolution copies of a video so the renderer can pick the cheapest one that still meets the current policy at each loop point. Snapshots and the lock screen fade in and out smoothly to match Apple's own behavior. The README ends with a note that Phosphene was started as a commercial project, but the author open sourced it under the MIT license after deciding the market for Mac video wallpaper apps was already crowded.