From a forum: “If you do not want to be bothered to figured out which you might need exactly then you could always install vlc-plugins-base, vlc-plugins-extra or just vlc-plugins-all which would of course simply install all of them.”

On which OS and version are you?

Of course. If you risk your life and freedom for the greater good on your own account you sure are a hero.

Great, more Signal users. Now do WhatsApp!

Try evince.

Loved it as a kid.