Hi sgartner,
Sorry, but (*.spp) files cannot be opened by double-click with Video Splitter.
We'll probably implement this feature in future.
Now you can do it by this sequence of actions:
1. Click right button on (*spp) file
2. Follow: Properties -> General ->opposite the "Application" string click "Change" button.
3. Choose "SolveigMM Video Splitter", click "Ok" button.