iMovie huge "high quality media" files

Question

Level 1

4 points

iMovie huge "high quality media" files

Hello everyone! After updating to MacOS sequoia operating system I had really hard time using iMovie. I am currently working on a small project and I found out that the library kept getting bigger and bigger in a strange way. I saw the file gaining 20gb in 2 minutes without even editing my project. Before Sequoia update I used to work on 5-6 projects like this before I have to move my library to an external disk. Anyone w/ same issue?

MacBook Air 13″, macOS 15.0

Posted on Oct 19, 2024 1:31 AM

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Answer 1

Oct 19, 2024 2:04 AM in response to Kostas_Gatos

The problem is almost certainly caused by iMovie creating huge ProRes render files which most Macs made in the last few years do not need.

Click on the iMovie icon in the menu bar at the top left of your screen and select Settings.

Click the Render Files Delete button.

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Answer 2

Oct 19, 2024 2:56 AM in response to Ian R. Brown

The only thing I can think is to delete the preferences which is something you should try whenever editing apps behave weirdly.

As you launch iMovie hold down the Option and Command keys until a window appears asking whether you want to delete the preferences.

Click Delete.

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Answer 3

Oct 19, 2024 2:42 AM in response to Ian R. Brown

There are lots of videos here about clearing space on iMovie but I suspect many of them are just saying what I said.

Clear iMovie Space

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Answer 4

Kostas_Gatos Author

Level 1

4 points

Oct 19, 2024 2:20 AM in response to Ian R. Brown

Thanks for your time! I already did that and "solve" my problem temporarily. But is there any permanent solution to my problem or I will have to delete those files after 20mins working on my project. I didn't have this issue before sequoia. Is there any system preference or setting that I can do, so my Mac isn't creating this proRes files?

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Answer 5

Oct 19, 2024 2:34 AM in response to Kostas_Gatos

Unfortunately you can't turn them off in iMovie the same as you can in Final Cut Pro.

I am not using Sequoia so I don't know whether that is the cause of the problem.

Could it be that your iMovie Library is massive? How large is it?

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Answer 6

Kostas_Gatos Author

Level 1

4 points

Oct 19, 2024 2:44 AM in response to Ian R. Brown

Nah, I just created a brand new library with just 1 project. I inserted a 50 min video and started editing it. When I saw the library file, it was 17gb and I saw it LIVE getting bigger and bigger. After 2 minutes it was 38gb. Now, as we speak it is 41 gb

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Answer 7

Tom Wolsky

Level 10

151,831 points

Oct 19, 2024 4:02 AM in response to Kostas_Gatos

Can you go into the library bundle and find the render files. See what format they are. I suspect it might be a higher quality ProRes. I don’t think there is a setting for that in iMovie but an update may have changed it.

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Answer 8

Oct 19, 2024 6:21 AM in response to Tom Wolsky

The strange thing is that I have just put a 24 minute video in the latest iMovie timeline on my M2 mini, added colour correction, comic effect, green screen and retimed it and my render folder is only 3.1 MB!

I can't get it to add render files.

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Answer 9

Rich839

Level 8

47,628 points

Oct 19, 2024 9:48 AM in response to Kostas_Gatos

Hi,

The comments by others in this thread have pretty much addressed the issue.

When you import a highly compressed movie into the iMovie timeline iMovie will unpack it for editing purposes. As a result, the file size will get larger. Try creating a new iMovie project and import into it a test video recorded with your iPhone. See if that provides you with any more information.

Also, to get more data, place onto your desktop the video that you are currently working with. Open it in QuickTimePlayer. Then do a Windows > Show Movie Inspector. In the pop-up box, check the data size and file format of the clip.

-- Rich

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