Help! How should I export my movie so I don't get glitches?

So, you have pretty much ruled out a systemic issue with iMovie or the Mac. It looks to me that it may be a format issue with the media that you are using. Not all Mp4 works with iMovie. It must be Mp4/AAC. AAC stands for Advanced Audio Coding. Try converting your Mp4 clip to H.264, Mp4/AAC with the free download, Handbrake. Do that even if the codec already is indicated to be Mp4/AAC. Re-rendering often cures the issue.

You can get Handbrake here:

https://handbrake.fr/

A simple way to do it is to open Handbrake and do a File/Open Source. Navigate to your video and choose it as the source from the resulting screen. Then do File/Start Encoding. Wait a couple of minutes for the conversion to complete. Then save and import the converted clip into iMovie.

I don't know what format that the Procreate app uses, or what Alpha algorithm. So can't tell whether they may be some issue there. Sometimes HEVC can be problematic, even though supported by iMovie.

To cover the bases, you might try creating a new project and seeing is it exports better from there. Also, you can try redownloading iMovie. To update/redownload iMovie 10, drag your iMovie 10 app from the Applications folder into the trash, but do not empty the trash. Sign in to the app store and open your purchases folder by clicking on your name at the bottom of the app store side bar.   You will see your purchases displayed, including iMovie 10. Redownload/update iMovie from there. If not successful, drag your present iMovie app out of the trash (if you moved it there) and return it to the Applications folder.

-- Rich

Hi, audreyromjue,

Try these easy to do procedures and see if one of them cures the problem:

Deleting 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 a new library. Reopen your old library to get back to your projects.  Deleting preferences is a safe procedure that will not cause data loss or disruption to your project.

Resetting the System Management Controller

Try resetting the System Management Controller (but no longer available for the new M1 computers:)

https://support.apple.com/en-us/HT201295

Resetting the NVRAM or PRAM

Try resetting the NVRAM or PRAM:

https://support.apple.com/en-us/HT204063

-- Rich

A 2 minute video should normally take less than 2 minutes to export unless it is something like 8K with multiple tracks and effects.

Do what Rich suggests and if you continue to have problems, tell us exactly how and what you are trying to export.

Have you exported successfully in the past?

I assume you have done this exact process before successfully?

If so, it is quite possible that there may be some corruption in at least one of the clips.

If that is the case, you will need to import the clips and re-do the project as Rich suggests.

It might help viewers of this thread diagnose the fault if you could upload examples of the "glitches"......... whatever they may be.

Never seen anything like it in a normal video.

I assume it is the big green triangles , the black and grey stretch lines from the chin and the black and grey triangle in the middle of "Quarantine"?

They do look like a special effect called "Shear" but how they have got there I cannot guess.

It is certainly possible that the issue resides with the Procreate app. Like, Ian, I have never seen in iMovie the type of glitches that you are experiencing. Try posting your question on Procreate's discussion forum. Here's the link:

https://folio.procreate.art/discussions/4

-- Rich

Slight correction . . . the name of the filter in Final Cut Pro is Scrape not Shear and this is one of the effects it produces, not dissimilar from your glitches.