FCPX keeps crashing, When used with media containing Dropped Frames

What cameras?

What codecs?

It seems rather unexpected that a major camera would often drop frames.

You mentioned a bug report... what exactly do you mean?

Note that if FCP crashes, the crash report is not very intelligible to most of us.

An Etrecheck report, on the other hand, may be useful.

Thank you for clarifying.

As far as I can tell, you already know the solution.

All cards are not born equal. For high data rates you need to use cards of a class appropriate for them.

https://www.sdcard.org/developers/sd-standard-overview/speed-class/

Dropped frames had a specific meaning for playback. Are you talking about visually corrupted frames in the original recording?

Whenever the application crashes you should trash the settings. Hold ⌥ ⌘ as you double click the library you want to open to launch the application. A dialog appears asking you if you want to Delete Preferences. If you don't do this while double-clicking your library, just opening the application, it will open a default Untitled  library.  

Please post an EtreCheck report https://etrecheck.com giving the application Full Disk Access in Privacy & Security System Settings. Copy the report and use the Add Text button to paste the result into reply box. 

This isn't simply "dropped frames." The camera file is structurally damaged. When processing damaged files, the behavior of any app will be unpredictable. It's a serious issue and must be addressed at the source.

My team has five A7SIIIs. So far, we've never seen this, but I am concerned about damaged data getting into our system. I have a background in software development. If you could provide me some example files containing these issues, I will try to write a simple app or script to find those. I also might be able to write a utility to excise the damaged frames, but I'm not sure.

Tom, could you please give advice about the best way to interchange files for this case?

OK I've spent a long time studying your camera files. In each case, the problem is caused by a damaged camera file. This will produce unpredictable behavior during playback. That behavior can vary from one machine to another and from one NLE to another.

E.g, on my M1 Ultra Mac Studio running FCP 10.7.1 on Sonoma 14.4.1, I could see the dropped frames but it would never crash. On Resolve Studio 18.6.6 it would sometimes hang. If I turned off decode acceleration in Resolve, they would play, but the problem would show up as a jump or jerk during playback.

My team has five A7SIII cameras, two FX6s and two RED cameras, but we rarely shoot high-frame-rate material on the A7SIIIs. On various forums I've seen periodic complaints about some SDXC UHS-II / V90 / U3 / Class 10 cards not working reliably in that camera at high frame rates.

I just tested 4k/120 10-bit 4:2:2 XAVC-S in one of my A7SIIIs, using a ProGrade 256GB SDXC UHS-II V90 U3 Class 10 card, and it worked OK. This camera is on firmware 2.10.

There is nothing that can be fixed in FCP to avoid this. The problem must be prevented at the source. The Lexar card you mentioned should work, but there have been some reports of counterfeit Lexar cards. In fact Amazon has a web page with tips on identifying them.

The test command I wrote is below. You would first need to install a static binary of ffmpeg. You can find that if you Google (in quotes): "ffmpeg static build for macOS". It should be placed in your search path. In the below command enter your pathname and filename. It will print the bad frames and an error for each one.

ffmpeg -v debug -report -err_detect ignore_err -i /Users/josephmarler/Movies/A7S3_120fps/JDM0977.MP4  -f null - 2>&1 | awk '/frame=/ {frame=$2} /error|warning|fail/ {print "Frame:", frame, $0}'

Terry, that's an excellent question. Ideally, the cards should always be formatted in camera, and files should not be deleted. Just offload them then reformat. Historically, deleting files in camera has been associated with problems.

I usually use WeTransfer as the link will appear in email notifications even if it removed on the forum. I have also exchanged emails and used Blip to transfer larger files https://blip.net

Maybe a bad batch of cards? Are the cards being formatted in camera?