Segmentation fault on startup on Linux v23.11.29

Good evening ladies and gentlemen,
I’m having a problem which did not appear before I did an update of the ubuntu system…
The shotcut version 23.11.29 which I did install previously to the system-update worked well…
now I’m getting a “Segmentation fault” at the end and at the beginning of the start a message is produced saying a lib is missing.
$ shotcut
libDeckLinkAPI.so: cannot open shared object file: No such file or directory

vnull

Segmentation fault (core dumped)

Now does someone knows a way out of this, as I need to finish my video-work somehow.
I’m not to experienced with Ubuntu I have to say…
Kind regards Michael

You did not say what you are doing at the time if crash. Is this a startup crash? How did you install Shotcut? On Linux there are multiple ways to get and run it. Which version of Ubuntu?

Some others do had a startup crash on Ubuntu 23.10 or later had to install the qt6-wayland package.

Hi, it does allways happen while starting shotcut.
I let the OS do the updates and as it didn’t wanted to startup I delete the SW and used snap to reinstall it with the same effect… not starting and providing the “Segmentation fault”. I have seen the commend about qt6-wayland and installed the wayland software to trail if the problem disapears… Anfortunatly it doesn’t…

What I wanted to trail out is to install a previous release of shotcut, but I’m not findinging a way to download an install it, only the release notes…
How is your opinion will it work?

Previous downloads are available here:

I get the same Segmentation fault (core dumped) with 23.11.29 AppImage or Snap installed
The Shotcut logo flashes for about 2 seconds, then closes immediately.

Ubuntu 22.04 LTS
Virtual Box 7.0 with libfuse2 and VirtualBox Guest Additions 7.0.12
VirtualBox_2023-12-10_10-48-43

AppImage versions 22.12.21 and 23.09.29 both open without any issues.
All AppImages locations : /home/dave/Downloads
Kdenlive 23.08.4 (Snap installed) opens without any issues.

FYI that message is not important. This optionally loads at runtime if you have the appropriate hardware and driver. I test the Linux release builds on my PopOS 22.04 and Ubuntu 20.04 where they work. There was a time when most Linux users were savvy enough to help troubleshoot problems. Sadly those days seem to be gone, but the pitfalls of desktop largely Linux remain. Hint: in a terminal, use source source-me if using the portable tar version, and then use gdb shotcut or strace shotcut to debug.

Ubuntu 22.04 LTS
Virtual Box 7.0

I just tested a fresh boot of that (not installed) from the 22.04.03 installer .iso but without Guest Additions (I doubt that makes a difference), and it works without the need to install anything or get updates. It also displays video and exports

If this is an installation where you have made significant changes please troubleshoot it and share your solution.

what you are missing is that’s a wayland session. in x11 everything works.

to make the latest release run in Wayland session, I replaced the usr\bin\lib in 23.11 with the that from 23.09 and added libQt6Charts.so.6
23.11 now runs in a Wayland session


Attempted to install libncursesw.so.6 from this instruction. This is the result.
VirtualBoxVM_2023-12-11_21-49-58

I attempted this as well. No success, and no Shotcut logo splash screen.

In an installed environment of Ubuntu 22.04 with all updates installed, the splash screen for 23.11.29 AppImage is in a different location than any other Shotcut AppImage.

I also tested a fresh boot (not installed) LinuxMint 21.2 Cinnamon. 23.11.29 AppImage loads fine.

To get gdb working you need to rm Shotcut.app/lib/libtinfo.so.6

The only way I reproduce the problem is when echo $XDG_SESSION_TYPE reports “wayland” and installing qt6-wayland fixes it, but only on certain versions of Debian/Ubuntu/derivatives depending on its Qt version. Shotcut includes all of the Qt 6.4.3 wayland plugins that their binary SDK installer includes. However, it seems more are needed as I see more unrecognized qt6-wayland libs than included with Qt SDK and Shotcut such as libqt6waylandcompositor6. However, the version of Qt included with Ubuntu 22.04 is 6.2.4, and I guess that is too old to use with Shotcut’s Qt 6.4. VirtualBox running Ubuntu 22.04 live/uninstalled on my Ubuntu 20.04 does not use wayland, but VirtualBox running 22.04 installed on my Windows 11 does. So, the only way to get Shotcut AppImage, portable, or Snap working on some machines is
A) first try installing qt6-wayland (or equivalent on your distro), or
B) disable Wayland (There are different ways, for example, Ubuntu 22.04 login screen, enter user name, click the gear icon in the bottom right corner, choose “Ubuntu on Xorg”.)
I suspect the Flatpak avoids these issues with its better managed runtimes.

Hi all,
thanks for your suggestions to solve my problem.
At least the wayland suggestion made it work, but still I can only start it from a terminal window and the shell and not via the desktop icon, but it’s working again!

I found that version 23.09 does start in a wayland session. So, I started to explore why. There are not a lot of difference. One difference is the new version adds a new Qt module called Charts. I was comparing the Shotcut.app/lib for other differences. The new version includes libQt6WaylandClient.so.6 but not version 23.09. Removing this file makes it work. However, it was added to fix this bug:

I reverted this change (addition of libQt6WaylandClient.so.6) for the next version.

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I was able to workaround this issue on Ubuntu 22.04.3 LTS by installing the lightdm display manager. (instead of gdm3)
sudo apt install lightdm

To switch between the display managers:
sudo dpkg-reconfigure gdm3

I think this basically switches the window manager subsystem from Wayland to X. To do this with gdm (GNOME display manager), logout (or on login screen on startup), first enter username, then click the gear icon to get a menu with options Ubuntu (Wayland) or Ubuntu on Xorg (X):


Finally, enter password and login. I have found this option to be sticky - saved between reboots until you change it again.