The format

XMP

The dynamic wallpaper information is stored in the "apple_desktop:solar" (xmlns:apple_desktop="http://ns.apple.com/namespace/1.0/") XMP metadata.

ap: dict. Basic information
- d: int.
- l: int.
si: array of dict. The solar-based dynamic
- i: int. The index of the image to use. You can use multiple times the same image and store it once.
- a: float. The elevation of the sun at the time and place the image is (supposedly) taken.
- z: float. The azimuth of the sun at the time and place the image is (supposedly) taken.

The dynamic wallpaper information is stored in the "H24" (or "apple_desktop:h24") XMP metadata.

ap: dict. Basic information
- d: int.
- l: int.
ti: array of dict. The time-based dynamic
- i: int. The index of the image to use. You can use multiple times the same image and store it once.
- t: float. The time when to change. It is between 0 and 1, 0 being 0:00, 0.25 is 6:00, 0.5 is 12:00, etc.

It requires knowing the solar position at the current position of the user.

This one is easy. The i value (in ti entries) is a decimal number between 0 and 1, and is a simple mapping of the daytime: