Ubuntu 20.04 LXC Containter:
sudo apt-get update && sudo apt-get dist-upgrade -y
sudo apt-get -y install coreutils wget apt-transport-https lsb-release ca-certificates gnupg2 software-properties-common
Optional:
sudo apt install libavahi-client-dev zlib1g-dev libavcodec-dev libavutil-dev libavformat-dev libswscale-dev libavresample-dev
sudo add-apt-repository 'deb https://apt.tvheadend.org/stable focal main'
sudo wget -qO- https://doozer.io/keys/tvheadend/tvheadend/pgp | sudo apt-key add -
sudo apt-get update
sudo apt-get install tvheadend