Artifacts in iMovie

Hi, geniusweb,

I don't think that Air Dropping the project caused this. Possibly a corrupt preference is causing it.

Try opening iMovie while holding down the Option and Command keys and selecting 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. Now see if the artifacts are gone.

Another thing you can try is to copy your media into a newly created project and see if that cures the problem. To do that, do an Edit/Select All, Edit/Copy, of the media in your project and then Edit/Paste it into the newly created project.

You could also try booting up in Safe Mode and, after everything loads, immediately shut down and reboot in normal mode. Then see if iMovie works properly.

-- Rich

I believe I found a solution that works. I was getting badly pixelated artifacts semi-randomly in my video when I would export to MP4 in any resolution. I was using video clips shot on an iPhone 8.

To resolve it, I rendered my heavily edited project to a 1080 Pro Res (.mov) file, which essentially flattened the timeline to a single video clip and did not have the artifacts created by the MP4 converter (I believe the converter is the issue, going from the raw iPhone format to MP4). I then created a new project and imported the .mov file I just produced. Once I added that to the new timeline, I was able to export it to any MP4 resolution with no artifacts. I've done this about a dozen times now with the same result - no more glitches/pixelated frames or transitions.

(Cross-posting here in case it helps.)

Thanks for posting back. So, your HEVC clips are the ones with the issue.

Try exporting from iPhone with the Automatic setting to get a more compatible format. Either that or try converting the already exported HEVC clips to H.264, Mp4/AAC, that Handbrake will do by default. Then import the converted clips into iMovie. See if either of the above works.

— Rich

— Rich

I have Converter all my videos and photos used in iMovie from high Efficiency Format to mp4 and jpg. After that there wäre no mir artifacts in the Rennerei video. Bit is was a lot of work to Exchange all the files. I have switched my iPhone back to Best compatibility.

I hope Apple will fix the problem soon!

I've had this problem happen with many movies I made with iMovie. The only fix I've been able to find that works for me is to 1st put all my clips into iMovie on my iPhone, then export it and import that file to iMovie. It's a complete PITA because then once you have end up with one long clip that you then need to cut & edit. But if I just import clips right in from iPhone to iMovie on my iMac I'll end up with random pixelation frames here & there throughout the project.

Anyway....hope that helps.

That's interesting.

When exporting out of iMovie from your cell phone, try using AirDrop to export the project itself (as opposed to the video) to your Mac. It will import into the Downloads folder on your Mac. Then you can open iMovie on your Mac and do a File/Import iOS Projects. The iPhone project should then import into iMovie for Mac as a project with editable clips instead of one long clip.

Or, if I remember correctly, I think you can double click on the project in the downloads folder and it will open in an iMovie for Mac project as an editable project.

See if that helps.

-- Rich

For the record I'm not on Catalina yet, so I don't think that the OS is the problem.

I've been working on Rich's suggestion and converted my clips to mp4 using handbrake. I've started piecing my movie back together and so far everything is looking really good. I'm willing to say that this is the solution until Apple gets it sorted out.

It's frustrating that this doesn't work out of the box using standard Apple products front to back.... This gear is too expensive not to work. Figure it out, Apple...

Finally a recent thread with the same problem I have.

I'm using the latest iMac with a Radeon 580X and an iPhone X for videos and photos. MacOS, iOS and iMovie with all the latest updates to this day (29.12.19).

The only solution I have found (trial and error solution):

Export video (4K) from Photos to folder on Mac, open video with Quicktime Player, export original 4K video to a lower resolution (1080p), import to iMovie, export finished product and then you don't have any artifacts and all...

This "solution" is terrible and kind of annihilates the purpose of having 4K. I was also extremely disappointed that the latest iMovie update does NOT fix this problem, which is extremely annoying!!!

Have you tried importing the iPhone video to your desktop and then using Handbrake to re-encode the video to H.264, Mp4/AAC? If not, try that, even if the video already is in that format. You can get Handbrake here:

https://handbrake.fr/

-- Rich

A recent poster found that the artifact was eliminated by splitting the clip just before the artifact, but not actually cutting out the artifact. In other words, just splitting the clip was enough to eliminate the artifact. Just passing it on.

Here’s the thread:

https://discussions.apple.com/thread/251098954

– Rich

Using Handbrake to convert all my clips first worked a treat. I just have to remember to do it each time. It's a pain, but it's quicker than learning Premiere.

-Jason

Actually, I meant to say "iPhone videos". Sorry. The artifacts could happen with photos as well, however. The posts I have seen refer to videos.

You might try taking out the photo and see if that resolves it. What format are the iPhone videos shot in? If it's HEVC perhaps that is the issue.

Also, you can do some troubleshooting.

Boot up in Safe Mode (see Finder help menu for instructions) and, after everything loads, immediately shut down and reboot in normal mode.

Create a new project with your media and see if it works O.K. there. Also, try with non-iPhone videos and see if the artifacts are gone.

Open iMovie while holding down the Option and Command keys and selecting 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. Now see if the artifacts are gone.

Open iMovie in a new library, copy your project there, and see if you can share out without artifacts. You can open in a new library by opening iMovie while holding down just the option key and selecting to create a new library in the box that appears.

Nothing that has been tried on this seems to have worked for other posters. It might be something that Apple needs to address.

-- Rich

-- Rich

Hmmm. The issue might be related to a quirk with the new updates. I think somebody mentioned that there is a supplemental Catalina update, but not sure. You might check in case there is a supplemental update that addresses this issue.

You might try using a different transition than cross-dissolve and see if that makes a difference. Or try adding the cross-dissolve by doing Edit/Add Cross Dissolve.

As a workaround, you can add a black background to your timeline and adjust its duration to the same duration as your video clips. Then put your video clips into the auxiliary time line above the black background. Then place your cursor on the video clip to reveal the fade handles (blue dot) in the upper corners of the clip. Slide the fade handles toward the middle of the clip to create a fade. Do that to adjacent clips. You then will get a cross fade that looks a little like a cross dissolve. Not perfect, but might suit your needs.

-- Rich

This problem is affecting my projects, exactly as described, and it ONLY affects footage shot using an iPhone. I have a 2017 MBP running Mojave. I have iMovie 10.1.14.

The only workaround I have found is exporting the video, noting where all the glitches show up, and then reimporting that raw footage into the video and exporting again. Sometimes I have to export a collection of clips and bring that in.

This is unreliable and time-consuming. It added three hours to my editing time for a recent 7-minute video. I have submitted a support request.

I really hope Apple figures out how to fix this problem. Everyone is telling me to switch to Premiere but I don't have the time now to learn new software.

Thanks,

Jason