Black frames in Event Clips, Timeline but not in Original File

I'm on FCPX 10.2.1 and have had something happen I've not seen before:
I imported clips into the library. I've added portions of said clips to a timeline. I've worked with the timeline successfully on 2 or 3 occasions, but today something isn't right.

The timeline has missing video within some clips, not skipped frames, but black during playback for various ranges of frames. The clip in the timeline, and in the event browser show the problem. If I "Show in Finder" and view the original clip within the bundle, the original source clip is still fine.

I've no idea what's up. Also, I've don't a lot of prep with marking Favorite segments and so on so is there some way to reimport the media maintaining the tagging I"ve done? Maybe force the clips offline, generate Proxy or Optimized media?

Launch FCPX while holding the Opt+Cmd keys, delete preference files.
Select the Library, go to the File menu, Delete Generated Library Files (All Render).
Re-boot your Mac.
See if this helps.

Thank you Ben for the quick reply.
I should've mentioned I did try; deleting preferences, repair permissions previously.
I now followed your steps, including again deleting permissions. I did be sure the All button was checked in the delete render step.

Unfortunately there is no change. The original file is ok within the bundle, the Event and Timeline clips are not.

Select one of the problematic clips in the Event Browser and optimize the clip. See if this solves the problem.

- Ronny

Beat me to it, Ronny! HA! Yeah, what he said...

Thanks guys. It appears I have a larger problem. I guess I should try reinstalling FCPX. Then, if needed re-import and review and rate the clips again. It's not that much backtracking. I'm sure it's a FCPX/media import only problem because absolutely everything else on this rMBP is working, including graphics intensive Adobe Lightroom CC.

Per the suggestion, when I transcode to optimize a single clip, seems to fix the problem. so then I select multiple clips, then optimize, I'm stuck, rainbow pizza wheel of death and the process progress is stuck at 0%. I have iStat Menus in my menu bar and I see there is no CPU/HD activity happening.

Rather than reinstall, I made copies of a couple other libraries, opened them did some edits, added and adjusted effects, did a short export... it all works. No beach balls, no missing segments, so I'm just going to create a new library and start over.

Have you tried opening a backup of your project? By default, FCPX would save backups on your system disk in Movies/Final Cut Backups unless you changed that location or chose not to save backups. It's possible that any backups may also contain the errors since FCPX saves them every 15 minutes but it's worth a try.

Thanks dgwvideo, I did revert to a couple project backups. The problem persisted. The problem affected 25% of the clips so I reimported those clips, all seems ok now.

The problem clips were from iPhones (5, 6+).
Is it possible to create a Camera Archive from iPhone video if it is connected via USB and using Import?
If that's possible and I had done that I would have saved some time by deleting the Event clips then reimport from Camera Archive.

iOS video handling here in FCPX is quite different from other connected cameras or camera cards.

I am not aware of the ability to create a camera archive from an iPhone. Apple's official procedure for dealing with iPhone footage is documented here: support.apple.com/kb/PH12741?locale=en_US

Bobbyco wrote: ... The problem clips were from iPhones....

I don't know if the following is actual info, but give it a try:

under low light conditions, iPhones vary the frame rate! A happily 30fps recording instantly has just 23 or 20,09 fps or whatever! .. which is a Nono on video processing => could be the reason for missing frames.

Workflow I was told:
open the original clip from the iPhone with Mpeg Streamclip; select 'fix time code'; export from Streamclip as Quicktime/proRes

Did this ever get resolved? I'm asking because this problem is still inside of FCPX 10.4.9. I think it has something to do with H.264 and H.265 clips, because those are the ones who have this problem or any other video glitch inside FCPX but not the file itself.
When I import a problematic file into Davinci Resolve or Adobe Premiere, the problems are gone. It's very odd.

bendermac wrote: Did this ever get resolved? I'm asking because this problem is still inside of FCPX 10.4.9...

The original problem was iPhone 5 and 6+ clips which appeared as black in the timeline. Is that the problem you mean? I haven't seen a general or widespread problem with black clips in the timeline. There are a few cases such as cross-library copy of clips with proxies and answer "no" to the copy proxy dialog which can sometimes cause black clips.

The clip thumbnails are cached low-res files which are generated automatically upon import. They are not deleted by File>Delete Generated Library Files, but can be manually deleted if you first create a folder to hold all cache items in Storage Locations>Modify Settings.

If you are running 10.4.9 make sure you have updated to Apple Pro Video Formats 2.1.2. That is done in System Preferences>Software Update.

No, it's not related to iPhone Videos.

It just happens sometimes with clips in AVC or HEVC. I don't know why.

I also updated to Pro Formats 2.1.2 right after I've upgraded to FCPX 10.4.9

Can you take one of the problematic files, play it in Quicktime Player, then do CMD+I and post the codec info?

Does it show as black every time in FCPX or is it intermittent? What if you create a new test library and import one problem clip from disk (not from an SD card) then try to skim it in the Event Browser? Does it play?

The black frame was always on the same spot, if it showed up.
I did a test library and it still was in the clip. But when opened in QT, Resolve or VLC it was clean.
Yes, the clip plays in the EB

bendermac wrote: ...The black frame was always on the same spot, if it showed up.
I did a test library and it still was in the clip. But when opened in QT, Resolve or VLC it was clean.
Yes, the clip plays in the EB

It is 10-bit HEVC, 1080p/59.94 fps. The file is pretty small, just 129 MB. Can you upload that to someplace where we can examine it and run tests on various hardware and software versions?

Hi Bobby, I am new to the forum and a bit late to this post however I just experienced the exact same problem. Here's how I fixed it 

I had just changed hard drives and moved my content over and finally started deleting some old footage, proxy footage and consolidating etc. I finally started a "new library" and dumped some footage into a new project under this library but then I used this footage in my old library to finish up an old project (from before my hard drive switch) for some reason, after my perfect export yesterday, when I logged in today 25% of the footage was black and apparently not "missing" and couldn't be "relinked" either. I had however deleted the footage from the new library once using it in the old library... hope this makes sense so far. In doing so it for some reason transfer the footage to the other library.. FIX - I simply dragged the footage from my hard drive BACK into the (new) library I had re-created and BOOM the project is fine...

I wonder if maybe your problem was using footage that wasn't consolidated to one library? I don't know why this is a problem as I have done this in the past without issue. Hope this helps but maybe it is still not resolved. 

Cheers