I would like to trim my videos in Photos app running on macOS Mojave, and consequently, reclaim valuable hard disk space.

  • Photos only appears to do a non-destructive trim, so it doesn't for up hard disk space.

  • When I edit with an external application such as quicktime, I am unable to save over the original video once my edits are complete.

  • I could export, and reimport the video into photos, however I would loose the metadata such as date, time, camera settings, and location.

Is there a solution to my problem?

  • what kind of trim are you talking about ?
    – Ruskes
    Dec 3, 2018 at 1:24

1 Answer 1


The only way to reduce the file size of a Video is to change its resolution (quality).

For that you will use the Export command.

Once exported to a lower resolution, the process is not reversible.

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Standard definition (480p) is good for standard-definition TV.

If the video will play on a high-definition TV or display, choose one of the high-definition formats: 720p or 1080p.

4K is used for ultra-high-definition TVs and displays.

720 is most common and a good balance between good picture at reasonable file size.

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