There have been similar problems, which have been recently fixed as described here: https://bugs.kde.org/show_bug.cgi?id=393478 and duplicates
Ubuntu should update to a newer version of okular to get the problems fixed. ** Bug watch added: KDE Bug Tracking System #393478 https://bugs.kde.org/show_bug.cgi?id=393478 -- You received this bug notification because you are a member of Kubuntu Bugs, which is subscribed to okular in Ubuntu. https://bugs.launchpad.net/bugs/1816196 Title: okular version in repository is too old, and fails with embedded movies To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/okular/+bug/1816196/+subscriptions -- kubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/kubuntu-bugs
