macOS offers three kinds of changing wallpaper. A Dynamic Wallpaper is a HEIC image whose stills brighten and darken with the time of day. An aerial is Apple's own video that animates as you lock or unlock, then rests as a still. A live wallpaper is a video loop that keeps playing behind your windows while you work.
| What the file is | When it moves | Who plays it | Work while you use the Mac | |
|---|---|---|---|---|
| Dynamic Wallpaper | One HEIC image holding several stills and timing metadata | It doesn't; it brightens and darkens through the day | macOS | None between picture changes |
| Aerial | A 4K HEVC video that macOS downloads from Apple | As you lock or unlock, and as the screen saver | macOS, with Apple's aerial player | None on the unlocked desktop |
| Live wallpaper | A video loop, usually H.264 or HEVC in an MP4 or MOV file | Continuously, behind your windows | A wallpaper app | Hardware decoding while the desktop is visible |
Dynamic Wallpapers: one image file, several stills
A Dynamic Wallpaper is a single HEIC image file that holds several versions of the same scene, plus metadata telling macOS which one to show. Apple describes them as images that brighten and darken based on the time of day for your current location. Some instead carry a light and a dark version that follow your Light or Dark appearance. When you pick one, the menu next to its name offers:
- Dynamic: gradually brightens and darkens with the time of day where you are.
- Automatic: switches from light to dark at sunset when Appearance is set to Auto.
- Light (Still) and Dark (Still): one fixed version of the picture.
There is no video in a Dynamic Wallpaper. macOS changes the picture as the hours pass and draws a still in between, so it costs what any desktop picture costs. Some download from Apple the first time you choose them. The history and setup steps are in dynamic vs live wallpaper on Mac; apps that build your own HEIC files are compared on Dynamic Wallpaper Club and 24 Hour Wallpaper.
Aerials: Apple's video, played as you lock and unlock
Aerials are Apple's slow-motion films, grouped as Landscape, Cityscape, Underwater and Earth. Apple's guide for macOS 26 and 27 says they animate as you lock or unlock your Mac, and that by default the aerial you pick is also your screen saver, played in slow motion. Shuffle Aerials is different: stills that change at an interval you set.
Each aerial is a 4K HEVC video that macOS downloads from Apple when you first choose it, and Apple's own player decodes it. You can't add a video of your own in System Settings: custom wallpaper there means photos, image files, folders and albums.
The video decodes only while it moves: on the Lock Screen, during the lock and unlock transitions, and while the screen saver runs. Once you are working, the desktop shows a still, so an aerial adds no decode work while you use the Mac.
Live wallpapers: a video loop behind your windows
A live wallpaper is a video loop, usually H.264 or HEVC in an MP4 or MOV file, that keeps playing at the desktop's wallpaper layer while you work. macOS has no setting for it, so it takes an app. Playback goes through Apple's Video Toolbox, which decodes supported H.264 and HEVC video in dedicated hardware; hardware video decode explains why that matters.
This is the only one of the three that does decode work all day, for as long as the desktop is visible. How much depends on resolution, frame rate, how many displays play their own loop and what the app pauses for. MacWall, for example, pauses behind full-screen apps by default and stops while your displays sleep. On macOS 26 (Tahoe) or later an app can also hand its video to macOS so it plays on the Lock Screen, the subject of how Lock Screen video works on macOS Tahoe.
What each one costs in CPU
- Dynamic Wallpaper: nothing between picture changes, because there is no video to decode.
- Aerial: decode work while it plays on the Lock Screen and as the screen saver; none on the unlocked desktop.
- Live wallpaper: continuous hardware decoding while the desktop is visible, and none while the app has it paused, because a paused wallpaper decodes no frames.
- Real-time rendered wallpaper (shader scenes, game-engine scenes, web pages): the most expensive kind, because every frame is computed instead of decoded. It is the model behind Wallpaper Engine's scene wallpapers on Windows; see why Wallpaper Engine doesn't run on Mac.
These are relative costs, not measurements. For figures from your own Mac, open Activity Monitor's Energy tab and compare a few minutes with the wallpaper playing and paused. Battery and energy basics walks through the test, and live wallpaper CPU usage on Mac covers what drives the CPU number.
Which one fits
- A desktop that follows the day without motion: a Dynamic Wallpaper.
- Motion only when you lock or step away: an aerial, or an aerial screen saver over any wallpaper.
- Motion while you work, your own clips, or a different loop per display: a live wallpaper app. Screen saver options are covered in how to change the screen saver on Mac.
Sources
- Customize the wallpaper on your Mac, Apple Support, accessed 6 November 2026
- Wallpaper settings on Mac, Apple Support, accessed 5 November 2026
- Use a screen saver on your Mac, Apple Support, accessed 6 November 2026
- Video Toolbox, Apple Developer, accessed 5 November 2026
- View energy consumption in Activity Monitor on Mac, Apple Support, accessed 5 November 2026
Keep learning
- What is a live wallpaper?A live wallpaper is a short video loop rendered at the desktop wallpaper layer instead of a still image.
- How macOS wallpapers workmacOS composites the wallpaper as its own layer below icons and windows, and only recent versions let third-party apps supply Lock Screen video.
- Hardware video decodeApple's media engine can decode supported H.264 and HEVC video in dedicated hardware, reducing the CPU work required for a 4K wallpaper loop.
- Video formats and codecsEncode wallpapers as H.264 or HEVC in an MP4 container, at display resolution, 24–30 fps, with no audio track.
- Resolution and displaysMatch wallpaper resolution to the panel's native pixels, and prefer one mirrored loop over separate loops on every display.
- Battery and energy basicsA wallpaper's battery cost is decode work times time on screen, so pausing when nothing is visible removes almost all of it.
- Why Wallpaper Engine isn't on MacWallpaper Engine is Windows software with its own DirectX 11 renderer, and its developer says there are no immediate plans for a Mac version.
- Lock Screen video on TahoeOn macOS 26 Tahoe and later the Lock Screen shows the system wallpaper and macOS plays it itself, so a video handed to the system keeps moving there after the app that set it quits.