gelma@gopt:/tmp/AudioLibro$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04
Codename: focal
gelma@gopt:/tmp/AudioLibro$ sudo apt-get install ffmpeg libav-tools x264 x265 bc
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package libav-tools is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source
However the following packages replace it:
ffmpeg:i386 ffmpeg
E: Package 'libav-tools' has no installation candidate
Andrea Gelmini