Still not going to be decoded in hardware on iOS.

You‘re spreading FUD. iOS (and other Apple platforms) had low level APIs to decode videos on hardware for years. Of course the video codec needs to be supported (AFAIK right now just H.264 and HEVC) but the container format doesn‘t matter, you just need to unpack it yourself.

Here‘s a - 6 year old - guide on how to set it up: https://stackoverflow.com/questions/29525000/how-to-use-vide...