MacWall's design goal is that you forget it is running. Video frames are decoded by Apple's media hardware through VideoToolbox and composited with Metal, so the CPU is not decoding pixels, and when nothing is visible, playback stops instead of running in the background.
Pause rules
- Pause on battery (off by default): on battery, stops playback once Low Power Mode is on or macOS shows the low-battery warning, and resumes on power. Pair it with Lower quality on battery, which caps playback at 1080p and 30 fps whenever you are unplugged.
- Pause in full screen: a full screen app covers the wallpaper, so decoding it is pure waste.
- Pause on display sleep / lock: always on. Nothing decodes while the screen is off.
- Pause on high CPU: yields automatically during exports, compiles, and other heavy work, then resumes when load drops.
- Pause on Low Power Mode: follows the system energy preference you already set.
Verify it yourself
- Open Activity Monitor → CPU tab.
- Search for `MacWall` and watch the % CPU column with a wallpaper playing.
- Switch to the Energy tab and check Energy Impact over a few minutes.
- Pause from the menu bar and watch both values fall to effectively zero.
With hardware-decodable media, MacWall moves video decoding off the CPU and stops the wallpaper decoder while paused. Actual CPU and Energy Impact readings vary by Mac, source video, display setup, and settings; use the steps above to measure your own setup. The methodology is broken down in the performance guide.
If usage looks higher than expected
- Check the source video. A 60 fps 8K import costs far more to decode than a 4K 30 fps loop. Re-encode using the guidance in Import your own videos.
- Check codec support. Unusual codecs can fall back to software decode. H.264 and HEVC always use hardware.
- Count displays. Separate loops on several 4K panels multiply decode work; mirroring one loop decodes once.
- Check for a competing wallpaper app. Two apps fighting over the wallpaper layer will both keep working, and both keep drawing.