I actually installed the packages mentioned in this
blog post of AlienBob.
Obviously I installed some more multimedia browser plugins in the past and now my plugins configuration tab looks like in the picture below.
My questions now are:
How does Firefox decide which one of the multimedia plugins to take?
Which do interfere with others? Which one make sense and which not?
Or in other words, which one I should disable and which one I should uninstall?
Is it possible to define priorities for the plugins?