Crashes when using Capture patch / QCAsynchronousQCView

pyramus's picture

Hi everyone,

I'm posting this to possibly save others the headaches and frustration I was encountering until a minute ago.

PROBLEM: Whenever I had a Capture patch embedded in a composition (about 90% of the time in my case), I couldn't safely restart the viewer -- 95% of the times QC would just stop responding or even crash. Luckily KinemeCore tried to auto-save the composition (thanks for that!) so I didn't really lose much work. However, I did feel losing a lot of time, self-confidence and maybe even karma with all those crashes.

SOLUTION: So, after a looooot of trial and error I found out it was the QCAsynchronousQCView that I (accidentally?) checked in the extended preferences that was bothering my system. After unchecking this and a restart of QC I didn't have any trouble.

N.B. Probably someone else here can better explain the actual reason for this trouble. I know these options are all unsupported, for advanced users and "at own risk" and all, but at least I'm hoping someone else with similar trouble will now find this post. I know I would have liked that :)

pyramus

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.

smokris's picture
Re: Crashes when using Capture patch / QCAsynchronousQCView

Could you attach a crash report from when QCAsynchronousQCView was enabled? I'm curious to see what broke.

(Also, over on the wiki, there's a list of private preferences along with our observations about what they do.)

pyramus's picture
Re: Crashes when using Capture patch / QCAsynchronousQCView

Hi smokris,

Thanks for your reply! Of course now when I need it, it doesn't crash properly with a CrashReport: it just hangs with the spinning beachball of death. So I'm attaching a manual sample during one of these hangs. (I didn't take the time before to save the text from the Crash Report, but I do remember seeing the same "EXC_BAD_ACCESS" part as in this sample)

Let me know if this gives you some clue or else I can keep trying to restart until I get a proper Crash Report, okay?

And thanks a lot for the link by the way :)

BTW -- I disabled my user plugins for this manual sample, to make sure to exclude those from being the problem.

PreviewAttachmentSize
Just Webcam Sample No plugins.txt51 KB

smokris's picture
Re: Crashes when using Capture patch / QCAsynchronousQCView

That spin dump appears to indicate deadlock between the main thread and the asynchronous QCView rendering thread. (Since this happens without any third-party plugins, I'm afraid we can't do much about it, and since this is an undocumented feature, I don't expect filing a bug report with Apple to help.)

I recommend just keeping QCAsynchronousQCView turned off.

pyramus's picture
Re: Crashes when using Capture patch / QCAsynchronousQCView

Yeah, that's what I've also decided during awfully long night ;-)

Thanks for looking into it!