• Install mythbuntu from DVD
• Enable the MythTV and Mythbuntu repositories in the Mythbuntu Control Center GUI
• Run (as root): apt update
• Run (as root): apt upgrade

• Set up some performance concerns in /boot/config.txt:
  

  gpu_mem=256

• Disable wifi in /boot/config.txt:

  dtoverlay=pi3-disable-wifi

• Put CPU in performance mode (as root):

  echo "performance" | tee /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor

• Turn off the screen saver:

  xset s off

• Disable other energy star features:

  xset -dpms

• Add PPA for Flirc (as root):

  curl -sLS http://apt.flirc.tv/add | bash

• Ensure pulseaudio is disabled
• Force audio to HDMI using the raspi-config command (as root)
• Ensure audio is set to ALSA:default in mythfrontend's config section
• Ensure volume is set to maximum and saved with alsamixer and alsactl store
• Set OpenMAX High Quality in video playback options, ensuring max CPUs is 4
• The “Advanced” de-interlacing won't work with OpenMAX, so adjust accordingly

For some combinations of hardware and software versions, the display that MythTV is using can become “deactivated”, usually due to the actual hardware display being switched to another input (as is common for TVs, switching to a different HDMI port, etc…).

To reactivate a display:

#!/bin/bash
SDN=":0"
VDN="HDMI2"
xrandr -d ${SDN} --output ${VDN} --auto

… you might have to find the values for SDN and VDN from .config/xfce4/xfconf/xfce-perchannel-xml/displays.xml

Technical Information Repository