iMovie huge "high quality media" files

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.

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

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.

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.

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

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?

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.

I have never heard of anything like that before!

What is your original video . . . .mp4, .mov, ProRes?

That Durant look like a render folder for a 24 minute movie.