There are many good guides to install Xubuntu like this one here so please refer to one of those.
$ sudo add-apt-repository ppa:mythtv-paulh/mythtv-qml
$ sudo apt-get update
$ sudo add-apt-repository ppa:mythtv-paulh/mythtv-qml-devNOTE: newer versions of the Apt tools will do the update automatically after adding a repository but doing it again doesn't harm anything.
$ sudo apt-get update
$ sudo apt install mythfrontend-qml
This will install MythQML and all required dependencies. It's that easy!
They remove some stuff from the desktop that you don't need, stop some annoying popups that you don't want and setup your PC to boot straight into the MythQML Launcher.
sudo nano /etc/gdm3/custom.conf
sudo apt install xfce4
This is a summary of the instructions found here
For me running with the compositor turned off in XFCE4 resulted in QML running a lot smoother.
Right click desktop -> Applications -> Settings -> Window Manager Tweaks -> Switch to Compositor Tab. Uncheck 'Enable display composing'
NOTE: I noticed on XUbuntu 20.10 turning the compositor ON resulted in smother animations and playback so YMMV \O/
If you are using an NVIDIA graphics card or builtin graphics make sure 'Sync to VBlank' is turned on to reduce tearing.
Right click desktop -> Applications -> Settings -> NVIDIA X Server Settings. Under OpenGL Settings make sure 'Sync to VBlank' is checked.
Having the screen locker kick in is very annoying and undesirable on an HTPC so disable it completely.
Right click desktop -> Applications -> Session and Startup. Switch to 'Application Autostart' and uncheck 'Screen Saver/Screen Locker (Launch screen locker program)'
We can disable the update notifier while we are here - Uncheck 'Update Notifier (Check for available update automatically)' and same for Power Manager (Power management for the Xfce desktop).
This is a summary of instructions found here
Having the 'System program problem detected' kick in is very annoying and undesirable on an HTPC so disable it completely.
If you want to disable these alerts permanently you need to disable apport. To do so, open the /etc/default/apport file by
sudo nano /etc/default/apport
and change the line enabled=1 to enabled=0
This is purly cosmetic but I prefer the screen background to be clean of any junk since I want the system to purely be an HTPC and nothing else.
To disable xfce panel and/or Thunar from starting in XFCE:
Start a clean xfce session with no application started.
Open XFCE settings manager > Session and Startup > Session tab.
Set “Never” under Restart Style for xfce4-panel and Thunar. Click Quit Program on each one. DO NOT do this for the desktop though or you will be left without any way to make further changes.
Click Save Session.
Logout and login again to test.
You can also remove the icons on the desktop while we are cleaning it up. Right click and select Desktop Settings, click the Icons tab and untick all the Default Icons.
You should now take a look at the post install hints and tips here