[Slackware] What do you think about the Alien repository, compared to Slackbuilds?

I wanted to record a video of the screen via simplescreenrecorder, so I installed it and its ffmpeg dependency via slpkg using the sbo repository (Slackbuilds.org). The program opens, but I can't record the video using the vp5 encoder because of a version incompatibility. So I tried to install the simplescreenrecorder using slpkg using the alien repository, which has more current versions, but the error below now appears when trying to open ssr:

root@darkstar:~# simplescreenrecorder
simplescreenrecorder: error while loading shared libraries: libavformat.so.55: cannot open shared object file: No such file or directory

At least ssr opened when I installed with the sbo repository. Is the alien a bad repository?