Qt4 interface not working for VLC

This is what happens if I try to run VLC:

main libvlc: Running vlc with the default interface. Use 'cvlc' to use vlc without interface.
main interface error: option qt-volume-complete does not exist
skins2 interface error: no suitable dialogs provider found (hint: compile the qt4 plugin, and make sure it is loaded properly)
skins2 interface error: cannot instantiate qt4 dialogs provider

I tried the command vlc -vv for more details, and apparently the Qt4 UI fails to load because there is an undefined symbol: _mali_clz_lu

It used to work until a few days ago. I've tried removing and installing both vlc and qt4 in all sorts of different ways (also deleting old config files and any kind of cache), what else can I do?

Solution 1:

1. Install dependencies

   sudo apt-get install git cmake g++ libqt4-dev qtbase5-dev qttools5-dev \
    qttools5-dev-tools qtquick1-5-dev qtscript5-dev libqt5xmlpatterns5-dev \
    libqt5svg5-dev libqt5webkit5-dev libssl-dev
   

2. UPDATE: Qt5.4 is now required. This is not in the default repositories.Check if you already have Qt 5.4 by typing

   qmake -version
   

   in a terminal window. If you don't have 5.4 or later then follow these steps to install it:

3. Download the latest version of Qt from http://qt-project.org/. The file you download is actually an installation script called something like

   qt-opensource-linux-x64-1.6.0-8-online.run
   

4. Move the installer to your Home directory and open a terminal window.

5. Give the installer execute permissions:

   sudo chmod +x qt-opensource-linux-x64-1.6.0-8-online.run
   

6. Run the installer:

   sudo ./qt-opensource-linux-x64-1.6.0-8-online.run
   

7. Follow the installation wizard and write down the installation directory (default: /opt/Qt. You can choose somewhere else if you want but make sure it doesn't have spaces anywhere in the path). Finish the install.

8. In your file browser, navigate to the installation directory and find the path to the Qt bin directory.

9. Add the bin directory to your $PATH environment variable so that MuseScore knows where it is. Modify the following command with the correct path as appropriate.:

   echo 'export PATH="/opt/Qt/5.4/gcc_64/bin:$PATH"' >> ~/.bashrc
   

10. Load your new $PATH variable.

    source ~/.bashrc
    

11. Complete! You can check the Qt installation was successful by typing

    qmake -version 
    

.