Ubuntu 20.04 obs-ndi.so libQt6Widgets.so.6: cannot open shared object file error

[gyalokai]

Hi,

I tried to install version 4.11.1 as described on an intel build PC (vga: nVidia GTX 1660 super) Ubuntu 20.04, with latest OBS (v29.0.2) but the obs-ndi plugin can not be loaded.

I found in the log this:

os_dlopen(/usr//lib/x86_64-linux-gnu/obs-plugins/obs-ndi.so->/usr//lib/x86_64-linux-gnu/obs-plugins/obs-ndi.so): libQt6Widgets.so.6: cannot open shared object file: No such file or directory

Module '/usr//lib/x86_64-linux-gnu/obs-plugins/obs-ndi.so' not loaded

What could be the problem? I could not find anything in connection with this file "libQt6Widgets.so.6" elsewhere.

EDIT:

git clone https://github.com/obs-ndi/obs-ndi.git
cd obs-ndi
.github/scripts/build-linux.sh

Error messages I get:
E: Unable to locate package qt6-base-dev
E: Unable to locate package libqt6svg6-dev
E: Unable to locate package qt6-base-private-dev
X script execution error
Callstack:
/root/install/ndi/obs-ndi/.github/scripts/utils.zsh/setup_linux:55
/root/install/ndi/obs-ndi/.github/scripts/build-linux.zsh:168
/root/install/ndi/obs-ndi/.github/scripts/build-linux.zsh:265

What do you need for debugging?

Thank you any help in advance!

[rcooke]

I'm dealing with this problem myself. I had a problem with my capture card driver under Ubuntu 22, so I rebuilt the machine with Ubuntu 20 LTS. I installed latest OBS (V28) and OBS-NDI (4.11.1) plugin binary. It appears the plugin was compiled with QT6 because my error was it could not find "libQt6Widgets.so". This lead me to a solution that should work for you as well: here.

The steps to fix involve adding a back-port repo to your system, then installing the QT6 packages:

sudo add-apt-repository ppa:okirby/qt6-backports
sudo apt update
sudo apt install qt6-base-dev libqt6svg6-dev qt6-base-private-dev

While this worked for me, I ran into another problem with the pre-made binaries. Now I get an error that my GNU C-lib is the wrong version. Again, a difference between Ubuntu 20 and 22. I have GLIBC_2.31 but the plugin binary wants GLIBC_2.34

So next I will try what you tried: compile from source. With the QT6 libs installed, this should work. Give a minute to find out...

ok. This is looking like the "Hard" way! I dealt with more missing packages, eventually hitting some that are going to be hard to install in Ubuntu 20. The last one was a "warning" escalated to an error, originallly in OBS Studio (it appears to be compiling OBS as part of the plugin build):

../src/obs-ndi-output.cpp:209:62: error: ‘bool obs_output_begin_data_capture(obs_output_t*, uint32_t)’ is deprecated [-Werror=deprecated-declarations]

Reading the release list, I thought 4.10.0 might work, since it was compiled for Ubuntu 20. But alas, when OBS tries to load it, I get the annoying "missing GLIBC_2.34"!

I think your best fix is to upgrade to Ubuntu 22. Or roll OBS and the NDI plugin back to the Ubuntu 20 compatible versions.

Edit: I was not able to find a working combination of OBS and NDI plugins. For Ubuntu 20 the package manager only offers OBS 29 or 25. I tried with NDI 4.11, 4.10 and 4.9, all got an error.

I upgraded my Ubuntu to 22.04LTS, and OBS to 29. Now the NDI 4.11 and 4.10 plugins cause OBS to crash. However, the 4.9 plugin seems to work!

Now if I could just figure out why my virtual sound patch cable is not working I would be good to go!

[gyalokai]

Hi Richard,

thank you very much for responding to my post and I also apologize, but I decided to let go of ubuntu version 20.04.

Since 20.04 is only supported until April 2025 (less than 2 years to go) and the server was a relatively young installation, I decided to upgrade to 22.04 instead.

From then on, everything went smoothly, I've been using it ever since, OBS 29.1.1 with NDI 5.x is running perfectly.

[paulpv]

So @gyalokai , this is no longer an issue and can be closed?

[gyalokai]

So @gyalokai , this is no longer an issue and can be closed?

Yepp, this issue can be closed, thank you!