VLC beta unable to start in GNOME unless QT_QPA_PLATFORMTHEME=gtk3

VLC has launched its beta release 4.0 about 2 years ago and now it is still beta. It has a new UI, which is modern and easier to use compared with VLC 3.0.

The VLC beta is installed from Packman extra, and it could run well under KDE plasma.

However, under GNOME, unless running source QT_QPA_PLATFORMTHEME=gtk3before typing vlc, it won’t start GUI. Below is output:

Warning: Ignoring XDG_SESSION_TYPE=wayland on Gnome. Use QT_QPA_PLATFORM=wayland to run on Wayland anyway.

(vlc:14409): GLib-GObject-CRITICAL **: 16:34:17.185: cannot register existing type 'GdkDisplayManager'

(vlc:14409): GLib-CRITICAL **: 16:34:17.185: g_once_init_leave: assertion 'result != 0' failed

(vlc:14409): GLib-GObject-CRITICAL **: 16:34:17.185: g_object_new_with_properties: assertion 'G_TYPE_IS_OBJECT (object_type)' failed

The GUI is a black box and not responding. I wish to use qt6ct to manage all QT programs and the environment variable is not proper to be set in .bashrc.

Thanks for your help.

I would begin by saying I’m merely curious and don’t know much about VLC or QT. I use mpv due to its minimal interface and easy to use shortcuts :wink:

To clarify, VLC 4 beta won’t work even when started with the environment variable QT_QPA_PLATFORMTHEME=gtk3?

I mean, on my device (wayland GNOME) VLC Beta will only work when QT_QPA_PLATFORMTHEME=gtk3

Other values or unset will not make it work at all.

Ah, so it does work with the env var, so why not add it to .bashrc?

I wish to use QT6CT to manage QT programs. Otherwise all QT programs will have an ugly GTK header… QT_QPA_PLATFORMTHEME=qt6ct is required by qt6ct.

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Okay, thanks. I understand now. :slightly_smiling_face:
You could modify the VLC .desktop file in ~/.local/share/applications/ and add the workaround environment variable QT_QPA_PLATFORMTHEME=gtk3 in the Exec line to have it apply only when opening VLC.

The original .desktop file may be in /usr/share/applications/. Copy it to local and modify to your liking!

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