Apple's video wallpaper format reverse engineered by kageroumado

Kageroumado has reverse engineered Apple's video wallpaper format and released Phosphene, an open-source toolkit that lets developers create custom video wallpapers for iOS [GitHub]. The implementation supports the same HEVC-based container format Apple uses, with precise timing and layering controls required for parallax effects and dynamic rendering.

Phosphene includes a Python-based encoder and detailed documentation explaining how to package videos into the .wallpaper container, bypassing Apple's locked authoring tools. The project also outlines how to sideload these files onto iOS devices without jailbreaking, using configuration profiles or MDM-style deployment.

The reverse engineering reveals that Apple’s format relies on tightly synchronized video layers and metadata tags for motion tracking, which Phosphene replicates accurately enough to pass system validation [Hacker News]. This opens the door for third-party apps to generate dynamic wallpapers programmatically—something Apple does not currently allow through the App Store.

Developers have already used Phosphene to build experimental tools, including live data-driven wallpapers and audio-reactive visuals. One contributor demonstrated a wallpaper that changes based on weather conditions pulled from an API.

Apple has not responded to the release, but past precedent suggests future OS updates could restrict sideloaded wallpapers. iOS 17 already tightened validation around dynamic assets, though Phosphene currently works on all devices running iOS 16 and later.