Install Tox messenger on Jessie.
 

Hello.
I want to install "Tox" messenger in Debian jessie x64. I added below line to "/etc/apt/sources.list":

deb https://pkg.tox.chat/debian nightly jessie

and then installed "apt-transport-https" and run "sudo apt-get update".

but when I want to install "qtox" it showed me below error:

$ sudo apt-get install qtox
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 to resolve the situation:

The following packages have unmet dependencies:
qtox : Depends: libavcodec-ffmpeg56 (>= 7:2.4) but it is not installable or
libavcodec-ffmpeg-extra56 (>= 7:2.4) but it is not installable
Depends: libavdevice-ffmpeg56 (>= 7:2.4) but it is not installable
Depends: libavformat-ffmpeg56 (>= 7:2.4) but it is not installable
Depends: libavutil-ffmpeg54 (>= 7:2.4) but it is not installable
Depends: libswscale-ffmpeg3 (>= 7:2.4) but it is not installable
E: Unable to correct problems, you have held broken packages.

Any idea?

Tnx.

Well, there are a couple issues I see here.

1) You're not following the official Tox installation instructions for Debian.
2) The packages you're trying to install are not in Debian's repositories. They may, however, be in the Ubuntu repositories. Or, if you don't want to potentially add instability from foreign repos, you can use pkgs.org.

The official Tox installation instructions for Debian don't tell you that you need the backports repository enabled.