https://forums.opera.com/topic/27463/bug-html5-h-264-codec-videos-no-longer-working-on-opera-54-0-2952-41-ubuntu-18-04-lts-x86_64-xfce/16

https://forums.opera.com/topic/23908/just-about-all-videos-won-t-play/76

https://forums.opera.com/topic/27537/can-t-play-facebook-videos-or-gifs-in-opera-w-linux-mint/40

https://forums.opera.com/topic/27375/opera-54-0-2952-41-streaming-videos-don-t-work-anymore/71