It does play in Damus. But in Primal it just goes to the website. 

 then it's not supported, I don't use primal or damus so I can't test it there, nor do I know how you claim to have literally seen people stream natively on those apps, it certainly wasn't NIP53  

 Dude 👇

https://primal.net/e/note105nsxch62nsppf0czf2kgqjmmvggsdu5r06sh5h64satjlqx0g6src4859 

 Whats the difference between those two links?

On the app, they both go to external links. One on zap.stream the other is to primal.

They just post the stream url naked in the note im guessing. 

 That's an MP4 they uploaded after the stream was over  

 https://files.v0l.io/5e1f91cf82cc0195ba356e825d1456a32603c4f5bd8cce8b1186dcb5188fa1ef.webp 

 So you are saying we can just upload a multiple GB video in an MP4 format?