@niepiekm said in Solving the problem of the Opera browser with video playback in Ubuntu and similar distributions (Linux Mint, KDE neon):

Looks like, on Ubuntu 20.04 the fix is as simple as installing the latest version of chromium-codecs-ffmpeg-extra from http://security.ubuntu.com/ubuntu/pool/universe/c/chromium-browser/ for Chromium your Opera version is based on. I just installed chromium-codecs-ffmpeg-extra_97.0.4692.71-0ubuntu0.18.04.1_amd64.deb and video playback in Opera 83 works again. No need to symlink libraries.

The solution worked for me (Opera 83)! First, I had to uninstall the newer codecs I had installed.