After I applied updates for Fedora 37 KDE today, QT6 got updated from 6.3 to 6.4 and MKVToolnix GUI crashes now every time when you launch it. I guess this needs a rebuild for QT6.4 or an update to v72.0 (or both). Reproducible: Always Steps to Reproduce: 1. Enter journalctl -f in a terminal 2. Start MKVToolnix GUI Actual Results: MKVToolnix GUI crashes, see core dump in the terminal. Expected Results: MKVToolnix GUI launches without crashing.
Created attachment 1927786 [details] MKVToolnix GUI core dump
Thanks for the report. I'll try to reproduce and confirm. Does downgrading Qt6 back to 6.3 help? Anyway, an update to 72 will happen in the next few days.
As I wrote in 2149046, this is due to qt6-qtmultimedia 6.4.1 having been built without an audio backend at all. Downgrading to 6.3.1 works fine. Upgrading MKVToolNix to v72 will not help. Full text of what I wrote over there: The error message appears when the Qt multimedia library wasn't compiled with any of the supported backends (gstreamer, PulseAudio, ALSA, WMF on Windows…). This should obviously not be the case on a Linux distribution. I just gave this a try with a brand new VM: * downloaded the Fedora 37 Desktop ISO * booted it, installed it to the hard disk with default options * rebooted into the installation, set up my user * logged in * installed my repository with sudo rpm -Uhv https://mkvtoolnix.download/fedora/bunkus-org-repo-2-4.noarch.rpm as described here * installed MKVToolNix v72 with "sudo dnf install mkvtoolnix-gui" (at this point a couple of extra packages were installed, among them qt6-qtmultimedia) * started mkvtoolnix-gui, and it came up just fine At this point the installed versions of the Qt6 libraries are: adwaita-qt6-1.4.2-1.fc37.x86_64 libadwaita-qt6-1.4.2-1.fc37.x86_64 qgnomeplatform-qt6-0.9.0-2.fc37.x86_64 qt6-qtbase-6.3.1-4.fc37.x86_64 qt6-qtbase-common-6.3.1-4.fc37.noarch qt6-qtbase-gui-6.3.1-4.fc37.x86_64 qt6-qtdeclarative-6.3.1-2.fc37.x86_64 qt6-qtmultimedia-6.3.1-2.fc37.x86_64 qt6-qtsvg-6.3.1-2.fc37.x86_64 qt6-qtwayland-6.3.1-4.fc37.x86_64 So we have no crash with 6.3.1. However, Qt 6.4.1 is available in the "updates" repo, which is enabled by default. So I updated everything with sudo dnf upgrade. Afterwards the library versions were at: qt6-qtbase-common-6.4.1-1.fc37.noarch qt6-qtbase-gui-6.4.1-1.fc37.x86_64 qt6-qtdeclarative-6.4.1-1.fc37.x86_64 qt6-qtwayland-6.4.1-1.fc37.x86_64 qt6-qtbase-6.4.1-1.fc37.x86_64 qt6-qtsvg-6.4.1-1.fc37.x86_64 qt6-qtmultimedia-6.4.1-1.fc37.x86_64 Now I do get a crash with 6.4.1. Downgrading to 6.3.1 with "sudo dnf install $( grep '^qt' libs-before.txt | sed -Ee 's/.[^.]+$//' )" immediately fixes the issue: the GUI starts again just fine. Also: [mosu@fedora ~]$ ldd /usr/lib64/libQt6Multimedia.so.6.3.1|grep strea libgstreamer-1.0.so.0 => /lib64/libgstreamer-1.0.so.0 (0x00007f54fbadb000) [mosu@fedora ~]$ sudo dnf upgrade …content cut… [mosu@fedora ~]$ ldd /usr/lib64/libQt6Multimedia.so.6.4.1 |grep stream [mosu@fedora ~]$ Version 6.4.1 is indeed not compiled against gstreamer anymore. This affects both the package provided by Fedora 37 itself (v71.1.0) & the one from my own repository (72.0.0).
I filed a bug report for qt6-qtmultimedia (https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=2150231) linking to the tickets with the updated information provided by Moritz Bunkus.
(In reply to Moritz Bunkus from comment #3) > As I wrote in 2149046, this is due to qt6-qtmultimedia 6.4.1 having been > built without an audio backend at all. Downgrading to 6.3.1 works fine. > Upgrading MKVToolNix to v72 will not help. [...] Thanks a lot for a detailed analysis, Moritz!
Fixed with the latest qt6-qtmultimedia update. (6.4.1-3)