Like many Linux distributions, openSUSE does not come out of the box with proprietary formats for legal reasons. Installing them is easy enough, however.
First, visit opensuse-community.org and install either the KDE or Gnome codecs. I use Xfce, so I choose the Gnome codecs.
Among other things, doing so will add the Pacman repository to your system. On one system I had previously added Pacman and after I had added the Gnome codecs I found myself with Pacman listed twice in my repository list. I deleted the previous instance and all was well.
Next, open the Software Management component of YaST. In the Repositories tab, select “Packman Repository”. Near the top of the window you will see an option to switch system packages to the Packman repository; do so. You will be prompted to download Packman’s versions of quite a few packages; do so. And with that you are done.
As a possibly easier alternative, Fluendo provides reasonably priced licensed codecs.
These notes refer to openSUSE 42.2 and 42.3, and were last reviewed 24 September 2017.