Solution: Install the newest libffmpeg.so file. Ór: install (evt. for the moment) Flashpeak-Slimjet and take the ffmpeg.so-file from the /opt/slimjet/ to the /opt/vivaldi/ directory. Now Vivaldi shows all. If you like you can remove Slimjet of course.
![Happy :happy:](./images/smilies/happy.gif)