How to Set a Video as a Screensaver on Mac (Any MP4)

macOS ships with gorgeous video screensavers. The aerial flights over Hong Kong and the California coast are 4K footage, streamed and played by the system itself, and they are the reason an idle Mac in an office looks like a screensaver ad.

What macOS does not ship is any way to use your video. There is no Add button, no import, nothing in System Settings that accepts an MP4. The machinery for video screensavers is all there, running Apple's clips; the door for yours simply is not.

Quick answer: macOS only reads .mov files from a protected system folder, so there is no built-in way to add your own video. Wallper does the conversion and install for you; the manual method and SaveHollywood are the free alternatives.

People have found three real ways through that door. One is automated, one is manual surgery on a system folder, and one is a veteran free utility. All three work. They are not equally pleasant, so here is the honest comparison, including the sharp edges nobody mentions.

Method 1: Wallper (the Automated Route)

Wallper handles the desktop, the lock screen and the screensaver together, so one short setup covers all three. You do it once:

1. Open Wallper Settings and turn on Use Lock Screen & Screensaver.

2. Open System Settings, Wallpaper and scroll down. A Wallper block now lives there. It can show a generic Extensions icon at first, which is normal.

3. Back in Wallper, click Set as Wallpaper on any video you like, from the gallery or your own files.

4. Wallper processes the video for a few seconds, shows the progress, and installs it. Done.

From then on, changing the screensaver is just step 3 again. No passwords, no system folders, nothing to redo after an update. The full walkthrough with screenshots is on the setup page. This one-toggle flow is for macOS 26 and later; on older versions the app falls back to its earlier install method.

Under the hood, Wallper re-encodes the video to the format macOS expects, handles resolution, color and timing, and installs the result where the system actually reads from. There are no background daemons and no launch agents. Playback runs through Apple's own pipeline, the same one the built-in aerials use, which is why it is Apple-notarized and keeps playing while your Mac is locked.

The whole flow is covered by the 7-day free trial, and the gallery it draws from is free to browse, so trying it costs nothing.

Method 2: The Manual System-Folder Method

This is the method behind most tutorials, and it is genuinely clever reverse engineering. macOS keeps its downloaded aerial clips in a system folder; put a correctly shaped file there, and the system will play yours too.

The recipe:

1. Convert your video to .mov. The screensaver system will not read .mp4. Many guides say to just rename the extension, and it often works, because MP4 and QuickTime containers are close cousins, but when the codec inside is not what macOS expects you get a saver that shows up and refuses to play. A real re-encode to H.264 or HEVC in a .mov container is the reliable version.

2. Make a thumbnail. Take a still frame, save it as a JPEG at something like 1920x1080, and name it to match the clip so System Settings can show a preview.

3. Copy both into the system folder at /Library/Application Support/com.apple.idleassetsd/Customer/4KSDR240FPS/. The folder is protected, so you will authenticate, and on some macOS versions you will fight permissions harder than that.

4. Reopen System Settings and pick your clip under Screen Saver.

It works, and I have real respect for whoever mapped it out. But go in knowing the failure modes: a macOS update can rebuild idleassetsd and quietly delete your files, a wrong codec fails silently with no error to Google, there is no uninstaller except you remembering what you put where, and you are editing a folder the OS considers its own. None of that is a catastrophe. All of it is why this method produces so many follow-up forum threads.

Method 3: SaveHollywood

The third door is SaveHollywood, a free, open-source screensaver plugin that has been around for over a decade, distributed these days through its author's GitHub. Install it, and it appears as a screensaver whose options panel accepts your video files; it plays them back when the Mac idles.

Where it fits: one specific video, zero budget, no interest in a wallpaper app. For that job it is entirely respectable, and recommending against free software that works would be dishonest.

Where it shows its age: it is a passion project maintained on its author's schedule, major macOS releases have broken it before, playback is software-side rather than through the system's native pipeline, and there is no library, no lock screen story, and no desktop story. You are also installing a third-party screensaver plugin, which is a category macOS trusts less with every release.

The Three Methods, Side by Side

What Makes Good Screensaver Footage

Whichever method you choose, the footage matters more than the mechanism, because a screensaver is watched differently from a wallpaper: full screen, from across the room, for minutes at a time, with nothing in front of it.

Slow wins. Apple's aerials drift for a reason. Fast cuts and camera shake that feel energetic for ten seconds feel exhausting for ten minutes. Long loops win too, since a 15-second loop repeats forty times in a ten-minute idle and even a clean loop point becomes visible through repetition. And darker footage is kinder to the screen and the room, especially overnight.

The nature and space collections are effectively purpose-built for this, and our 50 free 4K wallpapers list marks out plenty of calm, slow-moving candidates.

Screensaver, Wallpaper, Lock Screen: Know Which One You Are Setting

These three get conflated in every forum thread, so, precisely: the wallpaper plays behind your icons while you work (our guide to changing Mac wallpapers covers that side), the screensaver starts after the Mac idles, and the lock screen is the password prompt surface, which on macOS 26 can carry a live wallpaper of its own.

They are separate systems with separate rules. Wallper's whole pitch is making them feel like one: the same video on all three, set from one place, covered in more depth in the guide to setting a video as a live wallpaper on Mac and the comparison with Apple's Aerial screensaver.