How to change the default video player?
If your default video player is messed up, you can not open the right app after double click the files; download the below tools to fix it.
After downloading the tools, open it, and choose the right program as the default one.
Why Omniplayer/Fig Player can not set itself as the default Video Player?
Omniplayer & Fig Player are all published on Mac App Store. Due to sandbox limitations, we do not have this permission. And we follow Apple's guideline to use less permission to protect users' privacy.