How to install Jitsi from the unstable repo?

Given that Jitsi won't install nicely from apt how is the desktop client currently installed?

There's mention above of using the unstable repo.

These directions won't work for at least one other:

Jitsi
Download
Development
Documentation
    Support and Custom Development 

To use our debian/ubuntu stable repository:

install the Jitsi repository key onto your system

wget -qO - https://download.jitsi.org/jitsi-key.gpg.key | sudo apt-key add -

create sources.list.d file with the repository

sudo sh -c "echo 'deb https://download.jitsi.org stable/' > /etc/apt/sources.list.d/jitsi-stable.list"

update your package list

sudo apt-get -y update

install Jitsi

sudo apt-get -y install jitsi

Adding both repos:

nicholas $ 
nicholas $  wget -qO - https://download.jitsi.org/jitsi-key.gpg.key | sudo apt-key add -
OK
nicholas $ 
nicholas $  sudo sh -c "echo 'deb https://download.jitsi.org stable/' > /etc/apt/sources.list.d/jitsi-stable.list"
nicholas $ 
nicholas $  sudo sh -c "echo 'deb https://download.jitsi.org unstable/' > /etc/apt/sources.list.d/jitsi-unstable.list"
nicholas $ 

commenting out the stable repo and updating:

nicholas $ 
nicholas $ cat /etc/apt/sources.list.d/jitsi-stable.list 
#deb https://download.jitsi.org stable/
nicholas $ 
nicholas $ sudo apt update
Hit:1 https://download.jitsi.org unstable/ InRelease
Hit:2 http://archive.canonical.com/ubuntu focal InRelease                  
Hit:3 http://archive.ubuntu.com/ubuntu focal InRelease
Hit:4 http://archive.ubuntu.com/ubuntu focal-updates InRelease
Hit:5 http://archive.ubuntu.com/ubuntu focal-security InRelease
Hit:6 http://archive.ubuntu.com/ubuntu focal-backports InRelease
Reading package lists... Done
Building dependency tree       
Reading state information... Done
214 packages can be upgraded. Run 'apt list --upgradable' to see them.
nicholas $ 

and then trying to install:

nicholas $ 
nicholas $ sudo apt install jitsi
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Some packages could not be installed. This may mean that you have
requested an impossible situation or if you are using the unstable
distribution that some required packages have not yet been created
or been moved out of Incoming.
The following information may help resolve the situation:

The following packages have unmet dependencies:
 jitsi : Depends: libavformat57 but it is not installable or
                  libavformat-ffmpeg56 but it is not installable
         Depends: libavcodec57 but it is not installable or
                  libavcodec-extra57 but it is not installable or
                  libavcodec-ffmpeg56 but it is not installable or
                  libavcodec-ffmpeg-extra56 but it is not installable
         Depends: libavfilter6 but it is not installable or
                  libavfilter-extra6 but it is not installable or
                  libavfilter-ffmpeg5 but it is not installable
         Depends: libavutil55 but it is not installable or
                  libavutil-ffmpeg54 but it is not installable
         Depends: libswscale4 but it is not installable or
                  libswscale-ffmpeg3 but it is not installable
E: Unable to correct problems, you have held broken packages.
nicholas $ 

which then has unmet dependencies. Oh, the unstable repo:

nicholas $ 
nicholas $ cat /etc/apt/sources.list.d/jitsi-unstable.list 
deb https://download.jitsi.org unstable/
nicholas $ 

https://desktop.jitsi.org/Main/DebianRepository.html

Both `universe` and `multiverse` are enabled as:

nicholas $ 
nicholas $ 
nicholas $ sudo add-apt-repository universe
'universe' distribution component is already enabled for all sources.
nicholas $ 
nicholas $ sudo add-apt-repository multiverse
'multiverse' distribution component is already enabled for all sources.
nicholas $ 
nicholas $ cat /etc/apt/sources.list


#deb http://ag-projects.com/ubuntu focal main 

deb http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-updates main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse

deb http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
deb-src http://archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

deb http://archive.canonical.com/ubuntu focal partner
deb-src http://archive.canonical.com/ubuntu focal partner

#deb cdrom:[Ubuntu 20.04 LTS _Focal Fossa_ - Release amd64 (20200423)]/ focal main restricted

# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
#deb http://ca.archive.ubuntu.com/ubuntu/ focal main restricted
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal main restricted

## Major bug fix updates produced after the final release of the
## distribution.
#deb http://ca.archive.ubuntu.com/ubuntu/ focal-updates main restricted
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
#deb http://ca.archive.ubuntu.com/ubuntu/ focal universe
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal universe
#deb http://ca.archive.ubuntu.com/ubuntu/ focal-updates universe
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu 
## team, and may not be under a free licence. Please satisfy yourself as to 
## your rights to use the software. Also, please note that software in 
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
#deb http://ca.archive.ubuntu.com/ubuntu/ focal multiverse
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal multiverse
#deb http://ca.archive.ubuntu.com/ubuntu/ focal-updates multiverse
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
#deb http://ca.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse
# deb-src http://ca.archive.ubuntu.com/ubuntu/ focal-backports main restricted universe multiverse

## Uncomment the following two lines to add software from Canonical's
## 'partner' repository.
## This software is not part of Ubuntu, but is offered by Canonical and the
## respective vendors as a service to Ubuntu users.
# deb http://archive.canonical.com/ubuntu focal partner
# deb-src http://archive.canonical.com/ubuntu focal partner

#deb http://security.ubuntu.com/ubuntu focal-security main restricted
# deb-src http://security.ubuntu.com/ubuntu focal-security main restricted
#deb http://security.ubuntu.com/ubuntu focal-security universe
# deb-src http://security.ubuntu.com/ubuntu focal-security universe
#deb http://security.ubuntu.com/ubuntu focal-security multiverse
# deb-src http://security.ubuntu.com/ubuntu focal-security multiverse

# This system was installed using small removable media
# (e.g. netinst, live or single CD). The matching "deb cdrom"
# entries were disabled at the end of the installation process.
# For information about how to configure apt package sources,
# see the sources.list(5) manual.
nicholas $ 

The development of Jitsi Desktop (formerly SIP Communicator) ceased in the year 2017. It remained as hobby project (source) and to rip out code for other projects like Jitsi Meet. Therefore, if you really want to use Jitsi Desktop, consider to go for Ubuntu 16.04 EMS which is free (source) and an option till the year 2024. When it comes to newer Ubuntu versions:

Ubuntu 18.04 LTS

sudo apt install openjdk-8-jre libavcodec-extra libavfilter-extra libappindicator1
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/lib/jvm/java-8-openjdk-amd64/jre/lib/amd64:/usr/lib/jvm/java-8-openjdk-i386/jre/lib/i386
wget download.jitsi.org/unstable/jitsi-archive-keyring_1.0.1_all.deb
sudo dpkg --install ./jitsi-archive-keyring_1.0.1_all.deb
wget download.jitsi.org/unstable/jitsi_2.11.5624-1_amd64.deb
sudo dpkg --install ./jitsi_2.11.5624-1_amd64.deb
jitsi --debug

I have not tested what happens if the default JRE is installed, which is Java 11. If you run into issues, go for sudo update-alternatives --config java and change to Java 8.

Ubuntu 20.04 LTS

Same steps as for Ubuntu 18.04 LTS but one more thing:

a) H.264 video support: not required
You do not need the dependencies to FFmpeg, because those are just recommended libraries. Unluckily the Debian control file is wrong which declares those dependencies as required. Consequently, to run Jitsi Desktop edit that file…

b) H.264 video support: required
If you need the H.264 video codec (or the AMR-WB audio codec), you have to download the jitsi-lgpl-dependencies and compile Jitsi Desktop yourself:

sudo apt install build-essential openjdk-8-jdk ant libavcodec-extra libavfilter-extra libappindicator1
export JAVA_HOME=/usr/lib/jvm/java-8-openjdk-amd64

# optionally (if another Java was installed, change to Java 8)
sudo update-alternatives --config javac
sudo update-alternatives --config java

# optionally (when you have to re-build Jitsi Desktop)
rm -rf ~/.m2

wget github.com/jitsi/jitsi/archive/3ebd5dfac749e0677377dbc8643dfbbbf4b450fa.tar.gz
tar -xf 3ebd5dfac749e0677377dbc8643dfbbbf4b450fa.tar.gz
cd ./jitsi/
# replace the following file:
# ./lib/installer-exclude/jitsi-lgpl-dependencies-1.2-1-gfc49658.jar
ant make
ant -Dargs="--debug" run

Because the head of Jitsi Desktop is untested, compile errors can happen any day. Then, comment here and I have a look what is broken.