Editing movies using Quicktime

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Level 1

4 points

Editing movies using Quicktime

I'm using Quicktime on a Macbook Air M3 to edit small video clips (basically trimming them from 14sec to 9secs)

Software version is macOS Sequoia 15.3.1. Quicktime Player Version 10.5(1216.2)

As recent as last week I could bring in .mp4 files and save the edited version as an .mp4 with a .AAE file (what ever that is.) I could then select the .mp4 files to submit them to 3rd parties.

Today, when I trim the files there is no option to save but I can duplicate then save as a .MOV file but the file doesn't play back correctly. It seems to extend the first second out over the whole 9 seconds! I managed to find a work around by sharing the trimmed file but that's not very efficient. Anybody know what's going on?

One thing I did this time that was different, was to rotate the movie left before trimming. That shouldn't cause a problem though should it?

MacBook Air (M3, 2024)

Posted on Feb 18, 2025 6:21 PM

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Answer 1

drcder Author

Level 1

4 points

Feb 20, 2025 2:03 PM in response to Matti Haveri

Thanks for your response. I recorded the video using LiveViewStudio. It generates an .mp4 my golf swing on my ipad. I airdrop it to my macbook air, edit it, and then submit it to an instructor for review.

I just tried to edit the file without rotating it and it worked fine. It looks like rotating the image causes the problem. I'll contact LiveView to see if they can rotate the image prior to me downloading it.

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Answer 2

Feb 20, 2025 10:23 PM in response to drcder

If this helps any: rotating via QuickLook (select the movie in the Finder and hit the Space Bar) is fast and lossless because it just edits the rotation MatrixStructure in the metadata.

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Answer 3

Feb 20, 2025 2:53 AM in response to drcder

Maybe that .mp4 is corrupted or it is using a very long GOP? Where does that .mp4 come from and what app has encoded it?

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Editing movies using Quicktime