It's just a thin wrapper for https://github.com/qasim/Airstream (I think it's very lame that the README doesn't mention this), which I think would work in a watchOS app although I'm not 100% sure it would get approved.

I think I could take a look, but watchOS has different limitations for background apps You mean u want to run the app on Apple Watch?

I‘m thinking about an app on the watch, that acts as an airplay (video) receiver, so I can stream and watch videos on my wrist while cooking

Sadly the shairplay library only supports audio so that’s the best that I can do without using a different implementation

What a pity! Thanks for replying anyway! :)