Artifacts in iMovie

You can give your feedback directly to Apple at this link:

https://www.apple.com/feedback/imovie.html

You might consider using your Time Machine backup, if you have one, to revert back to Mojave and iMovie 10.1.12, where everything was working.

-- Rich

My setup:

MBP 15" 2018 with TouchBar, macOS Mojave 10.14.6

iMovie 10.1.14

iPhone 11, iOS 13.3

~90 video clips in HEVC format

I can confirm that not all iPhone videos causing those artifacts. After 22 tries of tweaking, trimming and replacing "damaged" clips with another clips (that also were taken on iPhone) I've managed to conquer those nasty artifacts in my 3min video. This is ridiculous!

I wrote a Bug report to Apple about this and I would recommend to do the same thing for everyone who is facing this issue. Apple will pay more attention if more bug reports will be reported. On other side they pay less attention if reported bug is old. So we should do this as fast and massive as possible.

https://www.apple.com/feedback/imovie.html

As far as I know the bug is at least one year old. I know because my equipment is the same (software updated) (iPhone 7 + iMovie) and only work on a «family video» each year. On Dec 2018 I was having exactly the same problem and trying to find an answer, to no avail. So it's a long story that seems to be ignored by Apple on each new version. :-(

Have all of you guys reported the issues with iMovie to Apple in a formal way?

https://www.apple.com/feedback/imovie.html

I did and I think it’s the only way to raise attention to this bug, this forum is only a self service info portal...

The more bugs we all report the more attention it will get in the priority list.

And I agree: transcoding is not an option, only an ugly workaround 😤

specially when we’re all using Apple’s ecosystem and not some weird third party tools or codecs!

Thanks to everyone who has contributed to this post. It have been very helpful to know I am not alone experiencing this issue.

I have a project that is around 25 minutes long, comprised of many clips cut down to 3-5 seconds. Most of the source clips are 4K iPhone, but there are also some HEIC clips pulled from Live Photos, some 1080 clips from a Sony camera, and a few other mics sources.

Exporting the source clips out to another format and recutting is just not practical.

I just tried the suggestion of exporting the entire movie to ProRes 4k file and unfortunately this did not fix the issue for me.

A few other things I have noticed

• I see the clips during playback in iMovie
• tweaking the affected clip by a few frames, making it a bit longer or shorter, will temporarily remove the artifact
• doing the above fix for the entire movie results in a whack a mole situation, where by the time I have fixed the entire project some of the artifacts
• the artifacts tend to come back in the same places
• the artifacts are a few frames from another nearby clip, sometimes rendered upside down and inverted or with mixed transparency over the underlying clip
• splitting the clip containing the artifact into sub clips (as suggested in one of these threads) did not help fix the issue
• setting the view timescale slider to about the middle and then slowly scrubbing the playhead over an artifact area will also temporarily remove the artifact if you go then jump back a minute or so and watch the affected segment in the iMovie preview panel

At this point I am just waiting and hoping that Apple will release an update for iMovie that will fix the issue. It seems to be releted to key frame generation IMHO.

kezwhite,

Try using your Time Machine backup, if you have one, to restore your iMovie 10.1.12 app.

-- Rich

Work with a smaller test video first.

— Ricbh

It's been affecting iMovie for over a year. I'm using 10.1.14 - same problem. The last update did not solve this.

-Jason

Just tried a new export of one of my projects. this time with no artifacts

My Setup:

• Macbook Pro 15"
• macOS 10.15.4
• iPhone 11
• iMovie 10.1.14
  • Quality: ProRes
  • Compression: Better Quality

Oh wow, this bug is getting bigger and bigger!

I’ve got the same problems since Catalina and tried so many things now, but I guess it’s just a really ugly bug in iMovie 😤

https://discussions.apple.com/thread/250814858?answerId=251560101022#251560101022

can I subscribe to one of your reported bugs or should I open another one?!

thx

I'm only doing small parts now to test, but I swapped out one of the clips that was being affected and it did fix that one, but then it happened in another place which was fine before.

In my projects this is not directly tied to transitions, since I do not have many of them.

Thx again Rich for the workarounds, I tried all of them before, but nothing helped 😕

My videos are all HEVC Full HD 60p taken on an iPhone XS. All projects containing those videos have issues, older iMovie projects with H264 videos from my older iPhone seem to be OK. Is it the same with you guys experiencing the same problems?

However, it's a pretty bad defect that came with the Catalina update and that needs to be fixed urgently...

I don't know of any way of reverting back to previous iMovie version without Time Machine, unless you have a non-Time Machine backup drive that contains the earlier version. Possibly you can find a website that can provide a download, or perhaps you have a backup older computer that you can copy it from.

-- Rich

--

Also so disappointed that the new release doesn't help. I even tried re-importing and creating new projects and all the other fixes suggested before in the new version in the hope that it would resolve. Then I finally just got my hands on a copy of 10.1.11, but if I try to open my projects or library in this version it terminates with at the error that one or more of the libraries were created with a newer version of iMovie. Seems I am completely at the mercy of Apple.

Hi, same problem here. But I can confirm it's not Catalina-related but older. I experienced the same bug in movies recorded with and iPhone 7 on iMovie 10.1.12 last year (and maybe before), when transitioning two clips with 'dissolve'. Videos are from the iPhone camera usually Full-HD, 60fps (HEVC). It happens only on some of them, but don't know why or if there is a pattern. On iMovie the preview window usually looks OK, but sometimes also shows the bug / jitter / big pixeles. It's more noticeable when exporting (sharing) to any format (usually Full-HD H.264 .mov) Removing the clips or transitions and adding them again sometimes work (on iMovie), but not always. I have been dealing with this for more that a year and praying on each new version it dissapears… but not yet.

--Alvy