Aspect ratio changes after export

The aspect ratio shouldn’t change after export. iMovie exports at 16:9 or 9:16, with black bars as necessary to make the video fit the 16:9 dimensions.

Try deleting preferences. To delete preferences open iMovie while holding down the Option and Command keys and select to delete preferences in the box that appears. iMovie will open in new blank library. Reopen your old library to get back to your projects. Now see if you can export properly.

— Rich

Without seeing the original display on the iMovie preview screen, I can't tell from your screen shot in the original post whether the aspect ratio changed or whether it was just the size that changed.

In any event, since the video exported and played fine on your desktop, iMovie did it's job and didn't change the size or aspect ratio. It is now an independent standalone video. Based on the information that you provided I would conclude that any size or aspect ratio change likely was done by your Android phone or Instagram. How does the video play on the VLC free download app or other video player? If you put the video in the Photos app, how does it play there? How does it play when you share the video from iMovie to email? Have you tried uploading it to You Tube?

-- Rich

It looks like both the size and aspect ratio changed. In the iMovie preview screen display, the image is cropped so as not to display the white vehicle in the driveway on the right. In VLC the display is not cropped, as you can see the white vehicle.

It is hard to tell from the screen shot in your original post whether the aspect ratio has changed. Is the bottom part of the image black? If so, the aspect ratio looks the same. Still, the size is definitely smaller.

I can't explain the change in size. I exported an iMovie project with a square video and then sent it to my iPhone with AirDrop. Both the relative size and aspect ratio were preserved, with the same black bars around it as shown in my iMovie preview screen.

Try exporting your video from VLC and then importing that video to your Android phone and see if works to preserve size and aspect ratio.

Also, what happens when you reimport the Android video back to your Mac? Does the size revert back to the original, or is it still the smaller size?

-- Rich

Yes, its very puzzling. I have no clue as to what might be causing it. You might try contacting Apple Support, as they have the capability of remotely accessing your Mac, that we don't have here. To contact apple support click on the Get

Support item in the upper right hand corner of this forum’s screen.  Navigate to a place where you can enter your

phone number.

If you contact Apple Support, would you post back as to what they came up with?

-- Rich

Hmmm. Would you post a screen shot of what you see in the iMovie preview screen?

-- Rich