Resolved iMovie renders part of a video as black

[franzkfk]

Hi,

I have a VERY SPECIAL project in iMovie and what iMovies does is, that it renders the video, but part of it is black. Not all of it. When I tried to render it a few times to check If some part specifically does it, actually it does not ... the time when the screen goes black is always different.
I tried new installation. I have tried reset settings.
I have M1 Air.
The thing is that when I render it in 720p it is fine ... when I do it in 1080p part of it goes black.

Could you help me?

 

[ColdCase]

When you share the project (export), does the result have black sections?

If not I'd say there may be CPU/GPU limits that, when exceeded, produces dark real time sections. I don't recall off hand, but there may be a setting to minimize, like working with proxies if iMovie supports it.

If you are seeing dark sections in the shared file, there may be some problem with transitions or there is actually dark sections.. .

 

[franzkfk]

Actually the result only has the black screen.

The project itself (loaded video) is absolutely fine. Again, the video rendered in 720p is fine. Only 1080p stops usually at 2 hour mark. Sometimes earlier, sometimes later. I just don't get it.

The thing is that I rendered this video in 1080p before and it was fine. I have made some changes, but I have gone back to the original state, because I thought that the changes itself was the problem - still the same.

I think I have the last thing and that is to clean the system and install it again.

 

[R S K]

Can one assume that you've done the obvious: restarted the machine (to flush memory etc.)?

You could try sending it to FCP (get the trial if you don't have it) and export it from there and see if it's the same. If it IS then there's something in your project that is too much for the M1, especially considering the length (did you say 2+ hrs.??). Which is what "the time when the screen goes black is always different" would strongly suggest. Let me guess… just 8GB?

Worst case I'd say you're reduced to exporting it in sections that are ok and gluing those together. OR transcoding all the footage to a more "resource friendly" (other than disk space) format like ProRes. 🤷🏼‍♂️ (something FCP will do for you btw)

working with proxies if iMovie supports it

Er… no, it doesn't. 😄 And that would at best improve the editing part, but he'd obviously still have to switch to the originals for output.

 

[ColdCase]

Er… no, it doesn't. 😄 And that would at best improve the editing part, but he'd obviously still have to switch to the originals for output.

I was thinking he was seeing black in the editing view, but he clarrified that.

It does sound like an out of memory type symptom. He's got less free space now than before so he is seeing issues now. If saving to internal drive, perhaps try sharing to an external drive.

Can not enough RAM cause this? I thought that just slowed things down.

 

[franzkfk]

OK - it is solved.

Thank you very much for your help.

Solution - cleaning the system to factory settings and install everything again.

Right now it works just fine.