macOS Sonoma introduced dynamic video screensavers, allowing your Mac to transition smoothly between static desktop images and engaging video visuals. These screensavers include breathtaking aerial views, cityscapes, landscapes, and underwater scenes. You can also add your own custom videos for a personalized screensaver experience. Here's how you can enable and customize both built-in and custom screensavers in macOS.

Method 1: Enabling Built-in macOS Screen Savers

Step 1: Open the System Settings app on your Mac. You can access it by clicking the Apple menu at the top-left corner of your screen and selecting "System Settings," or by pressing Cmd + Space to launch Spotlight and typing "System Settings." You can also find it by clicking the Apple logo at the top left.

Step 2: From the sidebar on the left, select "Screen Saver." You will see several categories, including Landscape, Cityscape, Underwater, and Earth. Each category contains various video screensavers you can use.

Step 3: Click on your preferred screensaver thumbnail. If it's your first time using it, your Mac will automatically download the video. You will see a download progress indicator and can cancel the download by clicking the "x". Once downloaded, the screensaver is ready to use.

Step 4: To preview the screensaver, hover your mouse cursor over the thumbnail at the top of the Screen Saver settings pane and click "Preview."

Step 5: Customize your screensaver by toggling the "Show as wallpaper" option. Enabling this displays the first frame of the video as your desktop wallpaper, creating a seamless transition when your screensaver activates. Additionally, you can set the screensaver to shuffle through various scenes at intervals ranging from every 12 hours to every month.

Step 6: Scroll down and you will see options to shuffle the Screen Saver between different categories or all available options. Just click the option you want to select.

Step 7: You can also use the Hot Corners feature on macOS to start the screensaver instantly. Click the "Desktop and Dock" on the left panel and scroll down. Then click the "Hot Corners" toggle button at the very bottom.

Step 8: Click any one of the four corners from which you want to start your screensaver and select "Start screensaver." Then click "Done." Now, when you move your cursor to the corner you selected for the screensaver, it will automatically start.

Step 9: To view the clock on your computer screen while the Screen Saver is running, click "Lock Screen" on the left. Then click the button on the right of the "Show large clock" option and select "On Screen Saver and Lock Screen".

Step 10: The Lock Screen page also lets you control when the Screen Saver will start automatically. Simply click the button next to "Start Screen Saver When Inactive" and set the time after which the Screen Saver will start.

Method 2: Adding Your Own Custom Video Screensavers

macOS also allows you to use your own videos as screensavers, giving your Mac a unique and personal touch. Here's how to set it up:

Step 1: Prepare your custom video file. The video must be in MOV format. If your video is in MP4 format, you can usually rename the file extension to ".mov" directly. If renaming doesn't work, re-encode the video using a tool like QuickTime or Handbrake. For optimal results, choose videos that loop smoothly, and consider removing audio tracks to reduce file size.

Step 2: Generate a thumbnail image for your screensaver. Take a screenshot from your video and save it as a JPEG file. Thumbnail dimensions can vary widely, but a standard size like 1920x1080 pixels is recommended for clarity.

Step 3: You'll need administrator permissions to place your custom files into the appropriate system folders. Copy your prepared MOV video file into the following directory:

/Library/Application Support/com.apple.idleassetsd/Customer/4KSDR240FPS

Then, copy your JPEG thumbnail image into:

/Library/Application Support/com.apple.idleassetsd/snapshots

Step 4: After placing the files, macOS will recognize your custom video as a screensaver option. To activate it, return to the Screen Saver settings in System Settings, locate your video, and choose it as your default screensaver.

Note: Sometimes, you may experience occasional issues where custom screensavers temporarily stop working, displaying a plain gray background instead. If this happens, toggling the "Show as Screensaver" option off and then back on typically resolves the issue temporarily. This glitch may be related to a stability issue, so ensure your system software is updated to the latest version to minimize this problem.

With these simple steps, you can easily enable, customize, and even create your own unique screensaver experience in macOS. Whether using built-in aerial views or your personal video collection, your Mac can now display engaging visuals whenever you're away from the keyboard.